Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: jon stead on September 24, 2017, 10:48:22 PM

Title: Misfires above 4,500
Post by: jon stead on September 24, 2017, 10:48:22 PM
Stumped again.

Engine still ticks over nice and rides nice at low revs but doesn't pull above 4500 rpm. Number 3 plug was sooty, so I put the original carbs back on, hard to say if better or not, but plug 3 still sooting  up. So unlikely the same fault is with both sets of carbs.

Checked Boyer Branson electronic ignition advance is ok, I.e. Full advance at 4,500 rpm.

There's a new set of D7 plugs in, gapped correctly. Valve timing is correct and valve clearances are correct.

Now looking at electrics again. Confirmed plug cap resistance is correct and have also exchanged cap 3 and 2 for each other. If number 2 plug soots up then it's the plug cap at fault. Will check tomorrow. Also going to check all electronic ignition wiring tomorrow, coils and ht leads.

Edit: Corrected cylinder numbers - sorry, Chris
Title: Re: Misfires above 4,500
Post by: kevski on September 25, 2017, 08:16:20 AM
Do you have both resistor caps and plugs, if so that would most likely be the problem.
Title: Re: Misfires above 4,500
Post by: JamesH on September 25, 2017, 09:49:45 AM
Jon - stupid question but check your main jets. I had an almost identical issue on a 750 recently. Previous owner had drilled out the main jets to prob 150-160 (should have been running 120's) and it was the last thing I thought to check (the mains were stamped 120). May be a red herring but worth looking at when you have the carbs off...
Title: Re: Misfires above 4,500
Post by: JamesH on September 25, 2017, 09:50:56 AM
Ignore the above - didn't see that you'd tried two sets of carbs with same symptoms...
Title: Re: Misfires above 4,500
Post by: jon stead on September 25, 2017, 10:12:27 AM
Do you have both resistor caps and plugs, if so that would most likely be the problem.
Thanks. It's got 5k ohm resistor caps and non resistive plugs
Title: Re: Misfires above 4,500
Post by: jon stead on September 25, 2017, 10:13:29 AM
Jon - stupid question but check your main jets. I had an almost identical issue on a 750 recently. Previous owner had drilled out the main jets to prob 150-160 (should have been running 120's) and it was the last thing I thought to check (the mains were stamped 120). May be a red herring but worth looking at when you have the carbs off...

Thanks. Jets are correct in both sets of carbs I've got. Fault stays the same, whichever set if carbs I've got on.
Title: Re: Misfires above 4,500
Post by: jon stead on September 25, 2017, 10:17:00 AM
It's all stop again :-(

Checking the plugs to see if the fouling had moved to number 2 after swapping the plug caps yesterday, and I've gone and stripped the threads on number 2 cylinder. It's always been stiff to screw in and out but now it's given up the ghost. Sigh.

Question: can a helicoil repair be carried out in situ?
Title: Re: Misfires above 4,500
Post by: Ashdowner on September 25, 2017, 10:52:57 AM
Yes someone I know just had it done. It's not a helicoil but a solid insert, and it's done very carefully so no crap ends up in the barrel..  dougie@thethreadmaster.co.uk  07775510166 is a guy in Hampshire who did it for him in Sussex, but there will be someone local to you who can do it.
Title: Re: Misfires above 4,500
Post by: Nurse Julie on September 25, 2017, 11:53:34 AM
This thread may help
http://www.sohc.co.uk/index.php/topic,13481.msg108229.html#msg108229
Title: Re: Misfires above 4,500
Post by: Rob62 on September 25, 2017, 12:18:56 PM
Be careful, its going to be very difficult if not impossible to avoid getting swarfe in the cylinder when fitting any kind of insert. Will need to be vacuumed out somehow.....
Title: Re: Misfires above 4,500
Post by: paul G on September 25, 2017, 01:02:04 PM
Be careful, its going to be very difficult if not impossible to avoid getting swarfe in the cylinder when fitting any kind of insert. Will need to be vacuumed out somehow.....

As far as I can remember the guy heavily greased the tap.
Removed the exhaust header and opened the exhaust valve.
At the same time he did the tapping he was blowing air into the head via the exhaust port!
Title: Re: Misfires above 4,500
Post by: kevski on September 25, 2017, 01:07:58 PM
Best quick fix is timesert not cheap, better fix is to have an ally insert made up, my Z1000 has all four done, and were done by a chap on the Z1 owners club who goes by the name of buzzard, even more expensive but beautifully done.
Title: Re: Misfires above 4,500
Post by: Nurse Julie on September 25, 2017, 01:17:11 PM
Be careful, its going to be very difficult if not impossible to avoid getting swarfe in the cylinder when fitting any kind of insert. Will need to be vacuumed out somehow.....

As far as I can remember the guy heavily greased the tap.
Removed the exhaust header and opened the exhaust valve.
At the same time he did the tapping he was blowing air into the head via the exhaust port!
Yes, that was the one I posted the link to above.
Title: Re: Misfires above 4,500
Post by: jon stead on September 25, 2017, 03:55:00 PM
Thanks all for your input.

I've ordered my kit up, insert rather than helicoil, and I already knew about using grease to catch the swarf. I like the idea of blowing air through the open exhaust valve. I was just going to fashion a thin tube on the end of my Henry vacuum cleaner and have a good suck around inside the cylinder before firing up.
Title: Re: Misfires above 4,500
Post by: Tomb on September 25, 2017, 04:29:32 PM
We use Demi-John rubber bungs in the exhaust, drilled for a 6mm air pipe to shove in.

https://www.homebrewcentre.co.uk/demijohn-solid-rubber-bung?gclid=CjwKCAjw0qLOBRBUEiwAMG5xMP5pIvm2OhcZyPo22W-0ttFRXA7E-yym9FFghhEiilg7_44bhWLPkRoCTZkQAvD_BwE

HTH ;)
Title: Re: Misfires above 4,500
Post by: jon stead on September 25, 2017, 04:45:39 PM
We use Demi-John rubber bungs in the exhaust, drilled for a 6mm air pipe to shove in.

https://www.homebrewcentre.co.uk/demijohn-solid-rubber-bung?gclid=CjwKCAjw0qLOBRBUEiwAMG5xMP5pIvm2OhcZyPo22W-0ttFRXA7E-yym9FFghhEiilg7_44bhWLPkRoCTZkQAvD_BwE

HTH ;)

Great idea, thanks
Title: Re: Misfires above 4,500
Post by: jon stead on September 26, 2017, 03:44:56 PM
Slept on it and decided to take head off. Going to have all four spark plug holes redone, just in case.

Whilst head's away, I've been checking the wiring on the Boyer ignition and it all seems to check out. I get 2.8kohm on both of the micro coils and I've swapped them over in the hope the sooty number 3 spark plug moves to 1 or 4.

Title: Re: Misfires above 4,500
Post by: Tomb on September 26, 2017, 04:42:42 PM
I've just snapped a plug off in the head on an XS1100 Yam, head off job too so feel your pain ::)

On the upside I'll lap the valves and fit new guide seals whilst its off.
Title: Re: Misfires above 4,500
Post by: jon stead on September 26, 2017, 06:53:26 PM
I've just snapped a plug off in the head on an XS1100 Yam, head off job too so feel your pain ::)

On the upside I'll lap the valves and fit new guide seals whilst its off.

Always a positive  :)
Title: Re: Misfires above 4,500
Post by: Rob62 on September 27, 2017, 07:13:37 PM
The right decision I think jon....
Title: Re: Misfires above 4,500
Post by: matthewmosse on September 27, 2017, 07:39:17 PM
Been there and done that on the snapped off spark plug with my bmw, I was dead lucky, the remains came out with the help of a flat bade screwdriver gently inserted and very gently seated with a few firm hammer blows so the blade bit into the sides of the plugs old threaded portion without spitting the ceramic bits into the cylinder, they just moved down a few mm but were held by the electrode tip. I still have a r80 bevel drive that needs a m12x1.25 timesert to repair it. The cost of the kits has  come down some way since that broke, but it has a lump of iron stopping a tap going through so it's a nasty job setting pre loads and shimmming up. Another reason to dislike bmw over Sohc Honda, too many jobs that mean building a unit up, shinning, testing pre load and then rebuilding with different shims. Honda managed to do things so much simpler yet they last better.
Title: Re: Misfires above 4,500
Post by: Moorey on September 27, 2017, 10:12:46 PM
Seems like a lot of unnessesary work and cost to repair a stripped plug to me. If you try and fail you have lost nothing if you succeed you would give yourself a pat on the back. But I have spent all my working life doing this kind of work.
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 07:09:59 AM
Going back to the original problem, I had a 500 that did almost the same, it was in 1972 and TBH even the Honda dealers didn't know what it was. Ran like stink when cold but as soon as it warmed up it wouldn't go above 5000 rpm, turned out to be a duff spark plug cap, fitted a new one (with those god awful metal shrouds which soon got binned) and the bike ran like a dream.  The bike was less than a year old so I didn't feel like tampering with it myself as it was under warranty, still took the Honda dealers almost 2 months to figure it out.

On Sunday night I swapped cyl 2 and 3 plug caps around and took bike out for a ride. It was dark when I got back so left bike to cool down before checking to see if fault had moved. Up bright and early on Monday morning, whipped the plugs out, no change. :-( 

It was as I put the plugs back in that I stripped number 2.

Going forward, when I get the head back on and the bike running again, I'm going to remove the Boyer Brandson ignition and reinstate the original coils and breakers. See what happens then.
Title: Re: Misfires above 4,500
Post by: kevski on September 28, 2017, 07:51:54 AM
If the problem does not move when you swap leads, you can rule out the boyer as rule, are you getting 12volts at the coils, i would be looking at valves and carburation.
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 08:48:35 PM
If the problem does not move when you swap leads, you can rule out the boyer as rule, are you getting 12volts at the coils, i would be looking at valves and carburation.

Cylinder head fully overhauled, valve timing correct. Number 3 plug sooting up regardless of which of the two sets of fully refurbished carburettors I have on. If it's not the electronic ignition then I am at a loss.
Title: Re: Misfires above 4,500
Post by: Johnwebley on September 28, 2017, 09:39:58 PM
The Boyer ignition fires all 4 plugs at once,

its called wasted spark system,

  the plug No2 is its pair,,can you swap leads 2 and 3 over?


 
Title: Re: Misfires above 4,500
Post by: K2-K6 on September 28, 2017, 09:56:56 PM
Can you test the compression as it is? I know you won't get a hot/absolute figure for it, but it would makes a valid comparison from one cylinder to the others and see if you have any major discrepancies.
Title: Re: Misfires above 4,500
Post by: Woodside on September 28, 2017, 10:16:14 PM
just a thought have you swapped the plugs around just because they are new doesnt mean they are all perfect...
possible duff one
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 10:32:13 PM
Can you test the compression as it is? I know you won't get a hot/absolute figure for it, but it would makes a valid comparison from one cylinder to the others and see if you have any major discrepancies.

Bike had a rebore, new pistons and rings less than 500 mile ago. I haven't retested the compression as I'm assuming it's good.
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 10:34:21 PM
The Boyer ignition fires all 4 plugs at once,

its called wasted spark system,

  the plug No2 is its pair,,can you swap leads 2 and 3 over?


 
I probably could do that, but at the moment I'm waiting to put the head back on and try the coils that I've just swapped over.
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 10:35:47 PM
just a thought have you swapped the plugs around just because they are new doesnt mean they are all perfect...
possible duff one

Yes, I swapped the plugs around, no change.
Title: Re: Misfires above 4,500
Post by: jon stead on September 28, 2017, 10:40:17 PM
Thank you everybody for your suggestions. I appreciate them.

If reverting to the original coils and points then I'm stumped.
Title: Re: Misfires above 4,500
Post by: kevski on September 29, 2017, 07:10:43 AM
Can you test the compression as it is? I know you won't get a hot/absolute figure for it, but it would makes a valid comparison from one cylinder to the others and see if you have any major discrepancies.

Bike had a rebore, new pistons and rings less than 500 mile ago. I haven't retested the compression as I'm assuming it's good.
One of the first things i would have done, may have broken ring/s ring in upside down valve blow by.
Title: Re: Misfires above 4,500
Post by: totty on September 29, 2017, 09:14:44 AM
I've just re read it all and I'd advise one further test with the Boyer before swapping back to points, swap parts around so the sooty one runs off both a different lead, coil, cap, plug - ideally having another cylinder run off the suspect set of parts. (they all fire at once and the leads unplug from the coils so this should be easy to setup)
I'd also check the unit has a really good earth and temporarily add an earth to the engine in case it's mounts are isolated by paint - I've seen bad earths act like a rev limiter.

I'd also follow the compression test advice once it's back together, but while the head is off I'd remove the barrels and check the bore and rings on the cylinder with the sooty plug.
The sooty plug should really only be caused by oil buring or a rich mixture and you've rulled out the rich mixture.

What happens at 4,500, does the engine tone go dull like one cylinders stopped firing or does it go erratic and stutter like a typical misfire. How consistent is it, is it always at 4,500 and immediately on hitting it or is in just in that ball park, does it recover immediately when the revs drop?

I wouldn't rule out two independent problems here. More gut feel than anything but I doubt the sooty plug is an ignition problem and swapping parts around will confirm this, however I also doubt that something which would cause a sooty plug would consistently only give symptoms at a set rpm.
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 09:45:01 AM
I've just re read it all and I'd advise one further test with the Boyer before swapping back to points, swap parts around so the sooty one runs off both a different lead, coil, cap, plug - ideally having another cylinder run off the suspect set of parts. (they all fire at once and the leads unplug from the coils so this should be easy to setup)
I'd also check the unit has a really good earth and temporarily add an earth to the engine in case it's mounts are isolated by paint - I've seen bad earths act like a rev limiter.

I'd also follow the compression test advice once it's back together, but while the head is off I'd remove the barrels and check the bore and rings on the cylinder with the sooty plug.
The sooty plug should really only be caused by oil buring or a rich mixture and you've rulled out the rich mixture.

What happens at 4,500, does the engine tone go dull like one cylinders stopped firing or does it go erratic and stutter like a typical misfire. How consistent is it, is it always at 4,500 and immediately on hitting it or is in just in that ball park, does it recover immediately when the revs drop?

I wouldn't rule out two independent problems here. More gut feel than anything but I doubt the sooty plug is an ignition problem and swapping parts around will confirm this, however I also doubt that something which would cause a sooty plug would consistently only give symptoms at a set rpm.

I've already swapped the coils but as yet, untested. As you say, easy enough to swap an ht lead so I can do that. I did try swapping the plug caps from 2 to 3 and vice versa and that made no difference.

Regarding your remaining questions, hard to pin point exactly, but now I think about it, no not consistently at 4500 revs and the recovery is not really noticeable as you reduce revs but bike rides lovely at revs below, say 4500. It's only when you open the throttle full that it bogs down and yes I suppose stutters as you call it.
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 10:15:05 AM
Can you test the compression as it is? I know you won't get a hot/absolute figure for it, but it would makes a valid comparison from one cylinder to the others and see if you have any major discrepancies.

Bike had a rebore, new pistons and rings less than 500 mile ago. I haven't retested the compression as I'm assuming it's good.
One of the first things i would have done, may have broken ring/s ring in upside down valve blow by.
As I say I never considered compression given the recent rebore and new pistons and rings. Surely I'd be burning oil if a ring was broken or in upside down?
Title: Re: Misfires above 4,500
Post by: AndyH on September 29, 2017, 11:03:07 AM
Stumped again.

Engine still ticks over nice and rides nice at low revs but doesn't pull above 4500 rpm. Number 2 plug was sooty, so I put the original carbs back on, hard to say if better or not, but plug 2 still sooting  up. So unlikely the same fault is with both sets of carbs.

Checked Boyer Branson electronic ignition advance is ok, I.e. Full advance at 4,500 rpm.

There's a new set of D7 plugs in, gapped correctly. Valve timing is correct and valve clearances are correct.

Now looking at electrics again. Confirmed plug cap resistance is correct and have also exchanged cap 3 and 2 for each other. If number 3 plug soots up then it's the plug cap at fault. Will check tomorrow. Also going to check all electronic ignition wiring tomorrow, coils and ht leads.

I may be repeating other responses Jon, but when you say "Misfires above 4500" are you referring to a jerky popping effect or just a "running out of breath" situation?
Title: Re: Misfires above 4,500
Post by: totty on September 29, 2017, 11:08:42 AM
It's only when you open the throttle full that it bogs down and yes I suppose stutters as you call it.

That (with jetting and carb cleanliness ruled out) would make me think fuel flow, the strainer, hose, pipes between carbs or float needles could have a restriction. Could be as simple as a kinked or internally collapsing fuel hose, that would be a good result, nice cheap and easy fix.


Also yes I'd expect a ring issue to result in burning oil, but it wouldn't take much to make one plug sooty.
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 01:33:28 PM
It's only when you open the throttle full that it bogs down and yes I suppose stutters as you call it.

That (with jetting and carb cleanliness ruled out) would make me think fuel flow, the strainer, hose, pipes between carbs or float needles could have a restriction. Could be as simple as a kinked or internally collapsing fuel hose, that would be a good result, nice cheap and easy fix.


Also yes I'd expect a ring issue to result in burning oil, but it wouldn't take much to make one plug sooty.

I've got two fully refurbished sets of carbs, both with their own fuel pipes, and problem the same whichever set of carbs and associated hoses are on.

The fuel strainer was renewed and a visual check of both tank outlets, with hoses removed, shows a steady uninterrupted flow of fuel.
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 01:37:57 PM
Stumped again.

Engine still ticks over nice and rides nice at low revs but doesn't pull above 4500 rpm. Number 2 plug was sooty, so I put the original carbs back on, hard to say if better or not, but plug 2 still sooting  up. So unlikely the same fault is with both sets of carbs.

Checked Boyer Branson electronic ignition advance is ok, I.e. Full advance at 4,500 rpm.

There's a new set of D7 plugs in, gapped correctly. Valve timing is correct and valve clearances are correct.

Now looking at electrics again. Confirmed plug cap resistance is correct and have also exchanged cap 3 and 2 for each other. If number 3 plug soots up then it's the plug cap at fault. Will check tomorrow. Also going to check all electronic ignition wiring tomorrow, coils and ht leads.

I may be repeating other responses Jon, but when you say "Misfires above 4500" are you referring to a jerky popping effect or just a "running out of breath" situation?

Again hard to say. It's not jerky as in surging back and forth, but runs less smooth and has no get up and go. Sorry I can't be more descriptive.
Title: Re: Misfires above 4,500
Post by: Pangloss on September 29, 2017, 01:50:30 PM
(Checked Boyer Branson electronic ignition advance is ok, I.e. Full advance at 4,500 rpm. )

Did u check that  advance curve beyond 4,500...?  Using a strobe light.... If the motor is not missing at 4500 but just going flat on power , sounds like ignition retard....at 4500
Title: Re: Misfires above 4,500
Post by: K2-K6 on September 29, 2017, 02:29:51 PM
I've been trying to think about that advance as it's electronic on these systems,  I believe. So it must have an internal count for rpm to allow it's logic to be applied. Don't know what internal architecture is or if it gets rpm count from one or both pickups. Could there be a failure to advance but still fire the plugs?

The rings do different things,  top compression obviously tries to work by stopping the pressure leaking download the bores. The oil control rings try to stop the oil going in the other direction. So if you get a compromised top ring you loose compression to the crankcase but won't necessarily get oil going the other way if the lower rings are functioning correctly. So you can get low pressure on one cylinder without appreciable oil loss.
Title: Re: Misfires above 4,500
Post by: totty on September 29, 2017, 04:03:23 PM

The fuel strainer was renewed and a visual check of both tank outlets, with hoses removed, shows a steady uninterrupted flow of fuel.

That pretty much rules out fuel flow, but since it's one of the few things you can rig up to test while the heads off it might be worth a quick test for a steady flow on each carb drain.
Title: Re: Misfires above 4,500
Post by: mickwinf on September 29, 2017, 04:39:10 PM
i would also remove valves on the affected cylinder in case one is bent or not seated properly
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 04:45:47 PM
(Checked Boyer Branson electronic ignition advance is ok, I.e. Full advance at 4,500 rpm. )

Did u check that  advance curve beyond 4,500...?  Using a strobe light.... If the motor is not missing at 4500 but just going flat on power , sounds like ignition retard....at 4500

I did use a strobe light and it's as Boyer say it should be, I.e. On full advance mark at 4,500 rpm
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 04:50:30 PM
i would also remove valves on the affected cylinder in case one is bent or not seated properly

The head was fully rebuilt, new valves, guides, recut seats, skimmed and all checked before reassembly. The fault was there before the head rebuild and still there afterwards.

Worth saying here, although I'm trying to forget about it, the head was only rebuilt because my fist made out of hams bent all eight valves and cracked the guides putting the cylinder cover on wrongly after checking the valve timing.
Title: Re: Misfires above 4,500
Post by: kevski on September 29, 2017, 05:24:51 PM
Are you getting a constant 12v at the coils, Boyer say 9v, if no the ignition will play up, frankly you need to start at the beginning when put back together, a few years ago i had Z thou that would do this, everything was as it should have been apart from exhaust, i put an original system on, problem solved, still puzzled as to why it happened like that.
Title: Re: Misfires above 4,500
Post by: jon stead on September 29, 2017, 05:35:32 PM
Are you getting a constant 12v at the coils, Boyer say 9v, if no the ignition will play up, frankly you need to start at the beginning when put back together, a few years ago i had Z thou that would do this, everything was as it should have been apart from exhaust, i put an original system on, problem solved, still puzzled as to why it happened like that.

I haven't measured the voltage at the coils but I will, good idea.
Title: Re: Misfires above 4,500
Post by: Rob62 on September 29, 2017, 10:15:42 PM
Just a simple thought but have you checked the fuel tank vent.... does the problem occurr immediately or after a few mins of running? Blocked or partially blocked vent wouldn't slow the fuel flow down immediately so a flow test might show up ok... but the flow would reduce after a while..
Title: Re: Misfires above 4,500
Post by: jon stead on September 30, 2017, 07:59:44 AM
Just a simple thought but have you checked the fuel tank vent.... does the problem occurr immediately or after a few mins of running? Blocked or partially blocked vent wouldn't slow the fuel flow down immediately so a flow test might show up ok... but the flow would reduce after a while..

Yes I did that. I took the cap apart and proved all clear, spring free etc. I even drove the bike with the filler cap open,  no difference.
Title: Re: Misfires above 4,500
Post by: Johnwebley on September 30, 2017, 10:58:41 AM
just a thought,

  I once had a faulty coil,worked ok on start up,but after a mile or so it stopped ,when it warmed up,

 that took ages to sort out
Title: Re: Misfires above 4,500
Post by: jon stead on September 30, 2017, 01:47:02 PM
just a thought,

  I once had a faulty coil,worked ok on start up,but after a mile or so it stopped ,when it warmed up,

 that took ages to sort out

Yes, I'm hoping it's a coil thing. I've swapped the coils but waiting now on the head coming back. If the sooty plug problem moves to 1 or 4 then it's the coil.
Title: Re: Misfires above 4,500
Post by: jon stead on October 04, 2017, 06:44:16 PM
Got my cylinder head back with four steel plug inserts now installed. Hopefully get it back on and running tomorrow before I go away again.

Watch this space!
Title: Re: Misfires above 4,500
Post by: Johnwebley on October 04, 2017, 08:17:10 PM
Got my cylinder head back with four steel plug inserts now installed. Hopefully get it back on and running tomorrow before I go away again.

Watch this space!


  fingers crossed !!
Title: Re: Misfires above 4,500
Post by: jon stead on October 06, 2017, 10:31:38 AM
Got it all back together, again, fired up no problem. Misfire still there but didn’t have time to ride it long enough to see if sooty plug has moved since coil swap. I’m away again so fault finding will continue upon my return.
Title: Re: Misfires above 4,500
Post by: jon stead on October 11, 2017, 02:32:53 PM
Removed Boyer ignition and coils. Fitted Dyna S back plate and the coils that came with the bike when I first bought it.
Fired up first time, dynamically set timing and away we went. Seemed better but still not right. Removed plugs, #3 sooty, but this could’ve been from before ignition swap. Cleaned plugs and regapped to 35 thou from 25 thou.
I also swapped my live and ground wires on the coils as I don’t know which terminal is positive or negative and even if it really matters?
Went out on it again and pulls much better. Going to keep using it and see how it goes. Rained off at present.
Title: Re: Misfires above 4,500
Post by: jon stead on October 11, 2017, 03:08:59 PM
https://m.youtube.com/watch?v=UP7NM4uKqKU
Title: Re: Misfires above 4,500
Post by: Rob62 on October 11, 2017, 07:09:44 PM
Wow!! Very nice  8) 8)
Title: Re: Misfires above 4,500
Post by: Johnwebley on October 11, 2017, 08:02:11 PM


   the plug gap should be 27 thou,

  non resistor plugs, and resistor plug caps ,

   

 
Title: Re: Misfires above 4,500
Post by: jon stead on October 11, 2017, 11:01:27 PM


   the plug gap should be 27 thou,

  non resistor plugs, and resistor plug caps ,

   

 

I’m using non resistor plugs and 5kohm resistor plug caps. I’m sure I read somewhere on Dynatek site, to set plug gaps between 0.035 and 0.040”
Title: Re: Misfires above 4,500
Post by: jon stead on October 12, 2017, 06:18:10 PM
Number 3 plug still fouling up. The other three are a beautiful grey/brown colour.

So, it’s not coils, ignition system, plugs or leads. It’s not carburettor or valve clearance.

All four cylinders are showing 100 psi on compression test.

I have found the Cap. Tach Gear, pn 12451323000, to be broken and this had been previously “stuck” back together, by P.O. Since I’ve had the cylinder cover off, this tachometer drive housing is now leaking. When I remove the plugs, clean Number 3, put it back in, the bike runs good for a few miles, then the misfire starts again. Could this oil leaking down into Number 3 spark plug well be causing the misfire and the sooty plug?

If it’s not this then the only other thing that’s specific to Number 3 cylinder is the exhaust.

As can be seen from my previously attached YouTube clip, the bike ticks over lovely and freely revs when in neutral. Out on the road, when it’s struggling to get above 5,000 rpm, if you pull the clutch in, the engine will happily rev right up.
Title: Re: Misfires above 4,500
Post by: mike the bike on October 12, 2017, 06:30:32 PM
That's caused by an air leak on the inlet rubbers of thereabouts.   I had the same fault on my 550four.
Title: Re: Misfires above 4,500
Post by: jon stead on October 12, 2017, 06:48:04 PM
That's caused by an air leak on the inlet rubbers of thereabouts.   I had the same fault on my 550four.

I tried the WD40 squirt trick around the rubbers on the intake side and noticed no increase in revs but I’ll certainly look at it again.

I thought an air leak would make it run lean and hot, as opposed to rich?
Title: Re: Misfires above 4,500
Post by: K2-K6 on October 12, 2017, 08:11:20 PM
Are you sure of that compression reading? It looks way too low to be running properly.
Title: Re: Misfires above 4,500
Post by: jon stead on October 12, 2017, 08:29:30 PM
Are you sure of that compression reading? It looks way too low to be running properly.

I can’t vouch for the accuracy or calibration of the gauge, but as a means of comparing one cylinder to another, they are all the same reading.

#1, 2 and 4 are running great, #3 has the mis fire resulting in the sooty plug.
Title: Re: Misfires above 4,500
Post by: K2-K6 on October 12, 2017, 10:36:38 PM
It doesn't sound logical I agree,  in that one cylinder differs in burn from others that are apparently the same.

That compression overall reading though I wouldn't by able to resist investigating further.  A slightly wide field view perhaps,  but if compression is genuinely that low then it's conceivable that the combustion burn time would be slow and as such it would limit the rpm under load to give the 4500rpm ceiling.

You could try advancing the timing to compensate and see if it would rev higher at all to give you more of a picture.
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 07:42:14 AM
It doesn't sound logical I agree,  in that one cylinder differs in burn from others that are apparently the same.

That compression overall reading though I wouldn't by able to resist investigating further.  A slightly wide field view perhaps,  but if compression is genuinely that low then it's conceivable that the combustion burn time would be slow and as such it would limit the rpm under load to give the 4500rpm ceiling.

You could try advancing the timing to compensate and see if it would rev higher at all to give you more of a picture.

I did advance the timing previously, and it made no difference. I agree that if the compression is low it would affect available engine power, but my problem seems to be on Number 3 only. Plus, the engine starts easily and ticks over lovely, revving freely under no load.

As stated previously, I now think that oil leaking from the tacho drive is affecting the quality of the spark on Number 3. I base this assumption on the fact that immediately after replacing the plugs, all cleaned up, the engine runs reasonably well, not perfect but good. Then, after say 5 miles, the misfire above 4500 rpm starts. I think this is when cylinder 3 stops firing, or not firing well, due to the fouled plug.

I have araldited the tacho drive in place whilst I source an intact drive, in the hope that this will stop the oil leak, and stop oil leaking onto Number 3 spark plug cap and HT lead.
Title: Re: Misfires above 4,500
Post by: totty on October 13, 2017, 04:07:16 PM
I still think no 3 sooting is a separate problem, these bikes will rev higher than 4500 on 3 cylinders.
Title: Re: Misfires above 4,500
Post by: mike the bike on October 13, 2017, 05:17:36 PM
I do too.  The fact that there's power to be found when the choke is operated suggests that it's running too lean (inlet airleak) and operating the choke enriches the mixture back to what it should be.
Title: Re: Misfires above 4,500
Post by: K2-K6 on October 13, 2017, 05:44:36 PM
It looks like the number 3 problem could be a symptom rather that cause. The plug caps if they are NGK in good condition are reasonably well protected against ingress and run without problems in rain conditions.

The problem with lower cylinder pressure is not necessarily one of outright power failing to pull the weight along but more of burn time of the mixture. It ultimately,  if too slow,  acts as a speed governor above which a loaded engine will not gain revs. It usually gives a very gentle and smooth tickover though.
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 05:47:51 PM
I do too.  The fact that there's power to be found when the choke is operated suggests that it's running too lean (inlet airleak) and operating the choke enriches the mixture back to what it should be.

Thanks Totty and Mike the Bike. Excuse my ignorance, but running lean wouldn’t cause the plug to soot up, would it? Also, there’s no evidence of overheating and as I say, I squirted WD40 on the intake manifold rubbers and there was no noticeable increase in engine revs.

Edit: Sorry, forgot to ask, where did I say it had power when the choke is operated? I have tried the choke in various positions whilst riding and there is no improvement in performance. All that happens is it bogs down as expected.
Title: Re: Misfires above 4,500
Post by: Johnwebley on October 13, 2017, 05:48:33 PM

  plugs 2 and 3 share the same ignition system,points,coils,and capacitor,can you swop the plug leads over? are the long enough?

 and then see if the trouble still stays on 3,

 that make it a carb issue,and/or exhaust

 BTW does the 3 exhaust silencer/tailpipe got hot ?or the same as the others ?
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 05:51:28 PM
It looks like the number 3 problem could be a symptom rather that cause. The plug caps if they are NGK in good condition are reasonably well protected against ingress and run without problems in rain conditions.

The problem with lower cylinder pressure is not necessarily one of outright power failing to pull the weight along but more of burn time of the mixture. It ultimately,  if too slow,  acts as a speed governor above which a loaded engine will not gain revs. It usually gives a very gentle and smooth tickover though.

Thanks K2-K6. I’m hearing what you’re saying but do not understand why only Number 3 would be sooting up.

Title: Re: Misfires above 4,500
Post by: K2-K6 on October 13, 2017, 06:08:02 PM
Yes,  I don't understand that either but you seem to have worked through many of the things that would affect the cylinder individually.

It's certainly giving you a bit of a run around,  something very peculiar going on with it.

Looks a great bike in the video though.
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 07:06:03 PM

  plugs 2 and 3 share the same ignition system,points,coils,and capacitor,can you swop the plug leads over? are the long enough?

 and then see if the trouble still stays on 3,

 that make it a carb issue,and/or exhaust

 BTW does the 3 exhaust silencer/tailpipe got hot ?or the same as the others ?

I changed the Boyer EI and associated coils plus leads, for a Dyna S with the original coil and leads, the only thing common after the swap was the plug caps and the plugs. The same problem is there on either ignition/coil/lead set up. I’ve swapped plug caps and plugs but fault stays on Number 3.

I have two sets of fully overhauled carburettors and the fault is the same whichever set of carbs is on. (Of course the intake rubbers and inlet manifolds are the same ones in each set up.)

The exhausts don’t look great from the outside, no idea what’s going on inside them, but suspect some serious corrosion. I was thinking maybe some intermittent internal blockage in number three exhaust, or not even intermittent, I guess if not exhausting freely, plug would soot up, then misfire occurs.

Regarding the temperature, I can’t honestly say there’s any noticeable difference, but I haven’t checked it that carefully. I did check when first back together, that all were warming up equally, and they were, but haven’t really checked after a run.

Title: Re: Misfires above 4,500
Post by: K2-K6 on October 13, 2017, 07:45:21 PM
Was it running before the rebore? If so,  what was it like?

Getting to more obscure stuff,  have you checked the tdc mark against actual tdc with a wire down cylinder 1 or 4.

Title: Re: Misfires above 4,500
Post by: K2-K6 on October 13, 2017, 08:04:09 PM
Just looked back at the thread from beginning,  the problem you said was with no2 plug sooting up,  you changed the caps over from 2 and 3 to see if it transfered,  that's what you have now. Do you have two new caps that you can put on those two cylinders?

Are you using the same caps for both the boyer and the points system by transferring them onto the lead sets?

Also, I think, you get an opposite effect it some circumstances. One coil fires two plugs,  if the resistance fails on one side then that route to earth will fire more easily as it has least resistance to impede it. But the good side with normal resistance may fail to fire at all if all the coil's energy is dissipated via the path of least resistance. So the failure exists of one side but the observable fault is effectively in the "wrong" position.
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 08:11:34 PM
Was it running before the rebore? If so,  what was it like?

Getting to more obscure stuff,  have you checked the tdc mark against actual tdc with a wire down cylinder 1 or 4.

It was running before the rebore but not really ridden due to carbs overflowing and severe engine oil leak. The carbs were sent away fir refurbishment and upon return, the bike was sent away to a “restorer” to sort out all the small faults and get it running as it should. We agreed to fit an EI system which he did. He fixed the oil leak and got it mot’d. He then informed me that he couldn’t get it to run right and that there was a serious problem with the carbs that I had had the temerity to pass onto him. Long story short, the bike came back to me in an unridable condition. Having set off down the wrong path of carburettors, which is how I now have two sets of fully overhauled carbs, the engine was rebored and the problem of poor running persisted- swine to start, erratic tickover, unridable. Eventually I found the Boyer coils wired in parallel instead of series. When I sorted that out the bike started on the button and ticked over lovely, as it does now.

I haven’t checked the TDC mark against the actual TDC but I can when I get home.
Title: Re: Misfires above 4,500
Post by: jon stead on October 13, 2017, 08:17:00 PM
Just looked back at the thread from beginning,  the problem you said was with no2 plug sooting up,  you changed the caps over from 2 and 3 to see if it transfered,  that's what you have now. Do you have two new caps that you can put on those two cylinders?

Are you using the same caps for both the boyer and the points system by transferring them onto the lead sets?

Also, I think, you get an opposite effect it some circumstances. One coil fires two plugs,  if the resistance fails on one side then that route to earth will fire more easily as it has least resistance to impede it. But the good side with normal resistance may fail to fire at all if all the coil's energy is dissipated via the path of least resistance. So the failure exists of one side but the observable fault is effectively in the "wrong" position.

Yes, sorry, it’s always been on the same cylinder even after I swapped the plug caps. I was initially calling it number 2 by mistake, senior moment. I should’ve gone back and corrected that. It is on Number 3 and always has been. Again, sorry for confusing you.

Makes sense what you’re saying about the path of least resistance.
Title: Re: Misfires above 4,500
Post by: matthewmosse on October 13, 2017, 11:29:55 PM
I've had a similar issue a long time ago, found one valve rocker eventually discoulored from heat so assumed the valve must be sticking so that engine got pulled, do you have another set of pipes to try, and possibly try new O rings on the inlet manifolds, or a spare set of inlet manifolds and rubbers. I'm just wondering if something is leaking air only when hot and leaning the mixture out on the inlet side, maybe smear silicon over everything - spraying wd40 doesn't always find inlet leaks. Were both sets of carbs overhauled by the same person? Possible if unlikely that perhaps something has been misplaced in a similar way on both sets of carbs, or a partially blocked tap on one fuel line starving one pot of fuel in preference to its neighbour.  I've found on the sidevalve motors I'e been working on recently I was getting counter initiative plug fouling and backfires when it was actually too lean ( air leak in the manifold and head bolts not properly tight, ran perfectly til worked hard then no power and backfires, left for 15 minutes it ran fine again. Whether engine was  hot the head bolts needed a good 1/2 turn to feel about right, they felt tight when it arrived. )
 Its a bit baffling on your bike, it seems you have covered most of the bases, is the battery and wiring good? Last time my 500 was in regular use it had a few issues with not revving out and with not charging, swapping 're then rec units from spares that worked fine when last used didn't resolve it, sadly neither did parking it in a shed.
Title: Re: Misfires above 4,500
Post by: jon stead on October 14, 2017, 07:07:44 AM
I've had a similar issue a long time ago, found one valve rocker eventually discoulored from heat so assumed the valve must be sticking so that engine got pulled, do you have another set of pipes to try, and possibly try new O rings on the inlet manifolds, or a spare set of inlet manifolds and rubbers. I'm just wondering if something is leaking air only when hot and leaning the mixture out on the inlet side, maybe smear silicon over everything - spraying wd40 doesn't always find inlet leaks. Were both sets of carbs overhauled by the same person? Possible if unlikely that perhaps something has been misplaced in a similar way on both sets of carbs, or a partially blocked tap on one fuel line starving one pot of fuel in preference to its neighbour.  I've found on the sidevalve motors I'e been working on recently I was getting counter initiative plug fouling and backfires when it was actually too lean ( air leak in the manifold and head bolts not properly tight, ran perfectly til worked hard then no power and backfires, left for 15 minutes it ran fine again. Whether engine was  hot the head bolts needed a good 1/2 turn to feel about right, they felt tight when it arrived. )
 Its a bit baffling on your bike, it seems you have covered most of the bases, is the battery and wiring good? Last time my 500 was in regular use it had a few issues with not revving out and with not charging, swapping 're then rec units from spares that worked fine when last used didn't resolve it, sadly neither did parking it in a shed.

Carbs were overhauled by different people, don’t believe it can be a sticking valve as the head was done by an engine race tuner with impeccable credentials. New o rings were used on the intake manifolds when the overhauled head was refitted. Battery is good, wired ng in parts is sketchy but the supply to the coils is good.

I don’t have another set of exhaust pipes to try, but I intend to get a pattern set.

I haven’t paid too much attention to the inlet side of things, other than checking the rubbers are intact and everything slotted together correct.

Thanks for your input, it is appreciated. I’m sure I’ll find it eventually, the problem is I work away and have big periods where I can’t work on the bike. Still this gives me time to postulate and return home full of new ideas and vigor.
Title: Re: Misfires above 4,500
Post by: K2-K6 on October 14, 2017, 08:50:42 PM
It sounds like you've brought it quite a long way already Jon and hopefully you'll get this problem sorted as well.

Just a couple more things to throw in the pot, have you tried it with the air filter removed from the air box?

Also,  a really odd one. Years ago a friend had a bike doing something similar revs wise,  turned out that it had a twist grip that was incorrect fitted into the bike's original switchgear that wouldn't open the carbs more that about half way,  it wasn't until looking for something else in carbs that it was spotted.
Title: Re: Misfires above 4,500
Post by: Johnwebley on October 14, 2017, 09:40:06 PM
just seen this thread

  http://www.sohc.co.uk/index.php?topic=9583.msg67421;topicseen#new

  his bike wouldn't runn above 4K

  see if anything helps
Title: Re: Misfires above 4,500
Post by: jon stead on October 15, 2017, 12:59:11 AM
just seen this thread

  http://www.sohc.co.uk/index.php?topic=9583.msg67421;topicseen#new

  his bike wouldn't runn above 4K

  see if anything helps

Yes I’d seen that thread previously. I know I’ve got 100 mains in both sets of carbs and also I only have the fouling of plug #3
Title: Re: Misfires above 4,500
Post by: jon stead on October 15, 2017, 01:02:27 AM
It sounds like you've brought it quite a long way already Jon and hopefully you'll get this problem sorted as well.

Just a couple more things to throw in the pot, have you tried it with the air filter removed from the air box?

Also,  a really odd one. Years ago a friend had a bike doing something similar revs wise,  turned out that it had a twist grip that was incorrect fitted into the bike's original switchgear that wouldn't open the carbs more that about half way,  it wasn't until looking for something else in carbs that it was spotted.

I’ve tried it without air filter, no difference.

I’ve also checked the throttle movement and the carbs open fully when the twist grip is operated. Thanks for the thought though, appreciate it.
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 01:33:45 PM
Hello All, the saga continues after my 5 weeks away.

Decided the exhausts had to be checked, especially Number 3 that has been having the sooty plug problem. I’d bought a cheap boriscope, to use with my phone, to stick down the exhaust and hopefully see something amiss.

I removed the exhausts, set up the biriscope, and stuck my probe down my number 3 exhaust down pipe. I didn’t get very far. I tried it down one of the other exhaust pipes and it went down easily. There is a partial blockage just on the first bend of Number 3 down pipe. I can see it when I look down the pipe. It looks like the inner pipe is indented, quite a bit, more than half the diameter, but there is no visible damage to the outer pipe.

This restriction is more than likely the cause of my lack of power problems, especially as everything else seems to have been ruled out. Has anybody any experience of anything like this and has anybody got a number 3 exhaust they want to sell?

Edit: I’ve added a picture below and found a right lower exhaust on eBay that I’ve made an offer on.
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 01:43:15 PM
Hopefully you can see the issue here
Title: Re: Misfires above 4,500
Post by: hairygit on December 03, 2017, 01:48:35 PM
Genuine or replica pipes????
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 01:57:08 PM
Genuine or replica pipes????

Genuine as far as I know.
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 02:27:48 PM
Ignore Alexander Armstrong singing in the background, I had Radio 2 on in the garage :-)

https://m.youtube.com/watch?v=l68XOgJ4QHI
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 02:43:03 PM
Does that look like an original Number?
Title: Re: Misfires above 4,500
Post by: Johnwebley on December 03, 2017, 03:16:54 PM
Does that look like an original Number?


  yes,

  bad luck with that happening
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 03:27:56 PM
Does that look like an original Number?


  yes,

  bad luck with that happening

I’m over the moon if this solves my problem. :-)

My offer on the eBay exhaust has been accepted so part should be with me this week. Then we shall see
Title: Misfires above 4,500
Post by: JamesH on December 03, 2017, 06:58:35 PM
Wonder how the hell that happened - looks like the inner skin of the pipe is indented?? Great if that’s solved the issue though!!
Title: Re: Misfires above 4,500
Post by: jon stead on December 03, 2017, 07:29:26 PM
Wonder how the hell that happened - looks like the inner skin of the pipe if indented?? Great if that’s solved the issue though!!

Ebay is saying expected delivery Tuesday, so hopefully will know shortly after that
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 08:09:05 AM
The “new” Number 3 exhaust should arrive today and hopefully will cure my fault, however, looking ahead, my old silencer part looks in better condition that the one I’m waiting on.

Has anybody successfully joined a downpipe to a silencer and if so how? I was thinking of an external collar possibly welded?

Any thoughts?
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 01:52:33 PM
Eureka! Exhaust arrived, fitted it, transformed. So much power now that the clutch is slipping but setting that up correctly will fix that. Over the moon. Now I just need the good weather.

I’m going to cut up the old pipe to see what has gone on inside there.
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 02:03:54 PM
https://m.youtube.com/watch?v=PuE_OIT550Q
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 03:28:26 PM
Not a lot I could've done with this
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 03:36:15 PM
Thanks to everybody for their advice and encouragement this last two years.

Four summers I’ve missed, chasing various faults but on a hiding to nothing with that lurking in the exhaust.

Can’t wait for this summer now.  :)
Title: Re: Misfires above 4,500
Post by: Nurse Julie on December 05, 2017, 03:39:32 PM
I wonder how the inside pipe ended up like that?. Summers not far away in the great scheme of things. 8)
Title: Re: Misfires above 4,500
Post by: K2-K6 on December 05, 2017, 04:01:40 PM
Wow! Well done for finding that Jon, who'd have believed it could be like that inside.

Looks like it's been like that from production process.

At least you'll be ready early for next summer now  :)
Title: Re: Misfires above 4,500
Post by: Johnwebley on December 05, 2017, 05:27:21 PM
as they say WoW !!

  guess it was an assembly fault for double skinning ,

  glad its sorted ,go and enjoy !!!
Title: Re: Misfires above 4,500
Post by: Woodside on December 05, 2017, 06:17:42 PM
blimey...
did you buy the pipes or were they on the bike when you purchased it?
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 06:32:03 PM
blimey...
did you buy the pipes or were they on the bike when you purchased it?

On the bike when I got it. It never ran correctly from day one. Serious oil leak from engine, fuel leaking out of carburettors. Then compounded by incorrectly fitted electronic ignition system and after sorting all these out, it still wouldn’t run right. It runs good now though. :-)
Title: Re: Misfires above 4,500
Post by: Woodside on December 05, 2017, 06:47:42 PM
great
are they genuine honda pipes or a copy...
Title: Re: Misfires above 4,500
Post by: Trigger on December 05, 2017, 07:05:33 PM
Some years ago I had a inner pipe rust away from the outer on the top and vibrate at above 1700 RPM. That had me stripping the head down to try and find the problem as the echo sounded like it was in the head.
Great to see you have it all sorted.
Title: Re: Misfires above 4,500
Post by: hairygit on December 05, 2017, 07:12:52 PM
I'd be tempted to e -mail photos of that to Honda, just to see if they respond!
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 07:32:51 PM
great
are they genuine honda pipes or a copy...

Genuine Honda
Title: Re: Misfires above 4,500
Post by: jon stead on December 05, 2017, 07:42:19 PM
I'd be tempted to e -mail photos of that to Honda, just to see if they respond!

Not a bad idea. Do you happen to have a contact email address for them?

I’ve read on Classic Japanese Bikes, that this has happened on other makes, Yamaha and Suzuki, and has been attributed to a manufacturing defect that gets worse when heated, I guess especially if it overheats when running lean.
Title: Re: Misfires above 4,500
Post by: Woodside on December 05, 2017, 09:34:32 PM
genuine honda ....christ
im just off to the garage to cut my set up to double check they are are ok
Title: Re: Misfires above 4,500
Post by: K2-K6 on December 05, 2017, 09:53:02 PM
genuine honda ....christ
im just off to the garage to cut my set up to double check they are are ok

 :) :) :)
Title: Re: Misfires above 4,500
Post by: Trigger on December 05, 2017, 10:05:59 PM
genuine honda ....christ
im just off to the garage to cut my set up to double check they are are ok

Woodside, can you cut up a set for me as it will save me doing mine  ;)
Title: Re: Misfires above 4,500
Post by: Woodside on December 05, 2017, 10:33:44 PM
ok just to let you know ive cut up 2 sets and all 8 are ok...
so all is good
Title: Re: Misfires above 4,500
Post by: Trigger on December 05, 2017, 10:45:51 PM
ok just to let you know ive cut up 2 sets and all 8 are ok...
so all is good

I will take your word on it, and not cut mine then to see  ;D
Title: Re: Misfires above 4,500
Post by: Woodside on December 05, 2017, 10:48:05 PM
all joking aside..its great when you nail a problem and get a fix...not surprised it took some finding thats a shocker
stick a few miles on the clock and enjoy
 :)
Title: Re: Misfires above 4,500
Post by: Johnwebley on December 06, 2017, 12:06:12 AM
ok just to let you know ive cut up 2 sets and all 8 are ok...
so all is good

I will take your word on it, and not cut mine then to see  ;D

  maybe I need to check mine,it runs out of steem above 10k
Title: Re: Misfires above 4,500
Post by: royhall on December 06, 2017, 07:30:02 AM
Ive arrived a bit late to this party. Up early today so thought I would read this from start to finish. Had a few ideas building until I got to the end. What a thriller of a finish that was, who would have thought to look there. The one thing that jumps out from this story is Jon's tenacity to see it through. Well done mate that's an inspiration for many on here to get out to the garage and get it done. Nice one Jon.
Title: Re: Misfires above 4,500
Post by: Bryanj on December 06, 2017, 08:10:43 AM
John, something wrong there i used to get miner out of the top of the red band in first 3 gears
Title: Re: Misfires above 4,500
Post by: jon stead on December 06, 2017, 06:48:07 PM
Ive arrived a bit late to this party. Up early today so thought I would read this from start to finish. Had a few ideas building until I got to the end. What a thriller of a finish that was, who would have thought to look there. The one thing that jumps out from this story is Jon's tenacity to see it through. Well done mate that's an inspiration for many on here to get out to the garage and get it done. Nice one Jon.

Thank you for the flowers, much appreciated. I can’t tell you how pleased I am to have finally got to the bottom of the problem. Been out on it twice today, as the roads were dry. Just loving it.
Title: Re: Misfires above 4,500
Post by: jon stead on December 06, 2017, 07:33:23 PM
Been down to the Council Recycling Village today and ceremoniously dumped the offending number 3 exhaust into the metal skip. Good riddance to it.
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