Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: totty on March 06, 2010, 01:20:57 PM
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Hi,
Having a bit of an MOT disaster today - It started bogging at around 3,500rpm on route and wouldn't go any higher unless I was very gentle on the throttle then refused to pass 4,500rpm. When I stopped outside it was holding revs, I turned it off while some space was cleared, it then started but ran really flat and wouldn't pull up the hill, stalled and wouldn't restart.
I'm thinking that it possibly overheated, but not sure if the cause is ignition or fuel related (vacuum leak maybe), or it could even be oil flow as I'm yet to trace why the oil pressure light doesn't work.
They're going to leave it to cool for a couple of hours before trying to start it for an MOT and I'm arranging a van to take it home :(
Any tips would be great, I've got a strobe so the ignition should be easy to test.
Cheers
Allan
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Sounds fuel related, i had a problem like this on one of my other bikes, try all the obvious things in fuel system starting with checking enough fuel is coming from tank, check the filter if you have one, mine turned out to be a blocked breather tube in the fuel tank so the petrol only dribbled out.
Pete
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The good news is it not only started for the MOT but passed and got me home ;D
Do you know what the flow rate should be or should I just look for a steady stream?
I've sprayed a bit of carb cleaner around to confirm that it's not a vacuum leak. I noticed the symptoms after riding just about 50 yards on the way home so I don't think it could be a symptom of overheating.
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Hi
Make shaw the fuel cap breather hole is clear and not blocked over time this gets dirt in it and if you use a tank bag it can bloke it off. all so i had once a badly fitted air box rubber this let air in and stopped it reeving and was just like yours was, refitted it correctly and was instance 100% better.
Paul
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Which bit do you mean by "badly fitted air box rubber" ?
The rubbers on the carb to inlet side are quite hard but spraying carb cleaner around then doesn't affect the tickover so they aren't leaking. I can't get my head around how the carb to aribox or even the join from the airbox to the filter housing could have an effect but I'll definitely check them.
I've also just remembered that the fuel level is quite low as I only put 5L in it, but I did run it with the tap set to reserve.
Cheers
Allan
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The filler cap breather seemed to be blocked as I couldn't blow through it, but I need to wait of the tax disk arriving in the post before I can test ride it.
Cheers
Allan
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What exhaust you got now, too much wadding will give exactly that symptom----I have a wide open Marvin on one that needed "Quieting" every year and it only ever got 1/2 way back from MOT
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It's a Motad. I've got no idea how it should sound so I don't know if it's been messed with.
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when my bike goes onto reserve it takes ages for the fuel to come through and it stops flowing a long way before it is empty. I always keep my tank as full as possible to avoid this problem. If your tank has been low, maybe you have picked up some debris from the bottom of the tank which has blocked jets in you carbs.
If your bike is overheating that is a different matter. How hot do you mean? You mentioned that you have no oil warning light. I would advise to find out the cause of that before riding it any further as you may cause damage if oil isn't getting around properly.
If your bike has electric start, take out the spark plugs to make it spin over easily on the button, remove some tappet covers and run the engine over on the starter motor and see if oil comes up.
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Many moons ago when I first started to ride I was out with some friends for the day when the bike started to give all sorts of revving problems & apparent overheating. It ran like a 8-stroke instead of a 4-stroke. I too took the valve/tappet cap off to check if oil was getting around, but the overheating was really cooking the lubricant. I was new to biking so I didn't know what to do next, so I started at the basics & checked the points gap. It had slipped & opened up the gap quite a bit. After regapping it went like a rocket...as far as a Honda 125s could in those days, but a lot better than previously. But I had learnt a lesson to check this sort of thing more regularly, especially as it was my only form of getting to Navy college in those days.
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The tank had 2L of old petrol in it when I bought it, that was replaced by 5L of fresh before riding it. I've removed the tap and found that the plastic strainer is missing which further increases the chance of dirt getting in. (any idea where I can get one of these at a decent price?)
I don't really have anything to gauge the temp against, overheating was assumed as it felt/smelt very hot and started easily once it cooled down. "8 stroking" would describe how it ran for the final few seconds before it stalled and refused to restart.
On the way home the bogging still occurred in but felt less harsh, more like a restriction. It idled fine and restarted easily when home.
So far for the oil pressure light all I've tested is the bulb and it was not the cause. I'll check for oil reaching the top end as advised and then look at the wiring. I also intend to drop the sump and clean the strainer.
The points had just been replaced so slippage may well be the cause, I've got the cover off and the tools next to it but work has been stopping me from getting any further with it.
Cheers
Allan
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Oil is reaching the top end, although I've got no idea of how much oil to expect.
The static timing is still spot on so the points can't of slipped.
I couldn't do much else by torch light.
Any idea how your supposed to get the front lower bolt out of the sprocket/pump cover to get to the oil pressure switch? There isn't enough clearance around it to get a spanner or socket on it. I've also found that the gear selector seal is leaking so I'll do that while I'm on.
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On mine there are screws not bolts holding the cover on. Sometimes people put a bolt in if the screw is lost/broken. However, if one does, it needs a washer so that it protrudes enough to get a socket on.
If oil is getting up to the top I am sure it is fine, and if the timing is right, I would investigate the dirty petrol theory. I have in-line filters on mine. They are really cheap to buy and keep all the grime from my tank away from the carbs. Before I installed filters I was stripping the carbs all the time which is a really boring job and they are a pain to get on and off.
Is your bike a 550 or a 500?
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The cover on mine has 2 allen key bolts and two normal hex headed bolts. I'm going to try and buy a box spanner or/or thinwall socket at lunchtime to shift the problem one, if they don't fit I might have to drill the head off.
If it's 6mm hose then think I have a spare filter lying around that I could use. I'd like to also replace the strainer in the tank to try and keep the grime out of the tap.
I certainly don't want to frequently remove the carbs, I had a right battle with them to get them back on last time.
The road tax arrived today so at least testing it wont be a problem ;D
It's a 550.
Cheers
Allan
EDIT - The bolt is now out, had to grind a box spanner down to paper thin walls.
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I've just had it out for a test ride and it still wont rev >:(
The fuel flow looked good when I removed the pipe. I'm still running on reserve though as I don't want to fill the tank until I've got a new strainer for the tap.
No fuel filter is fitted (yet).
Cap breather is clear.
Carb rubbers look fine.
I forgot to check the exhaust so I'll have to go back to that.
Points gap and static timing are both spot on.
I'm yet to try the strobe, maybe it's not advancing???
The oil warning light switch is faulty, doesn't earth even when not running. Oil did reach the head when tested.
After adding another 5L of petrol I can now coax it up to 7,000rpm. I can also now clearly feel that anything over 1/4 throttle causes the bogging, it looks like I'm going to have to take the carbs off to clean the mains and emulsion tubes and set the float heights.
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I stripped the carbs, found a blocked main on number 2, a blocked pilot on number 4 and float heights a bit out. Also fitted a fuel filter, checked the timing with a strobe and fitted a working oil pressure switch.
It ran like crap at first then sorted itself out and was fine for an hour but lost all power just as I was arriving home - This was after sitting in a traffic queue for some time.
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The loss of power may have been caused by overheating (happened on my 550K3 many years ago queuing to get into Silverstone).
Keep an eye on the fuel filter - I don't like them and believe that Honda would have fitted one if it was really needed. My K2 had those little in-line filters (two) but they got clogged easily and then the engine stopped.
(Maybe you will say that that crap would have gone into the carbs and the engine would have stopped anyway...)
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I'm hoping that's all it was, the queue was quite long, I'll see what it's like when I next ride it.
The filters easier to clean than the carbs :-)
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This seems to be a very annoying time consuming problem for you, i do hope you get it fixed soon as these problems can really put you off a bike, i had four months where i could not solve a problem with one of my kawasaki's it turned out to be an intermittent problem with the electronic ignition, it drove me round the bend, and i ended up hating the bike for quite a while
Pete
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My patience is starting to wear a bit thin with it.
Once it's sorted it's going to take me a while to build up enough confidence in it to go any distance which is a shame as this was supposed to be my distance bike with the monkeybike staying in use for local rides.
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Do you ride the monkey bike much? I have a Honda dax which i dont really ride much, i bought a chinese 125 engine for it as well as a loom and all parts needed to turn the bike in to a 125 12 volt, but i lost interest and have not touched it in two years, i will keep it as they rise in value all the time, maybee some time i will do the engine swap just to see how it goes
As for your bike with the problems, take your time and do everthing as properly and cleanly as you can so you dont have to keep re-doing the same thing, sooner or later you will hit the jack pot and all will be good.
Pete
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I use it to get to work when the weather's nice and also do one or two of the many organised runs.
Mines just a Chinese z50 copy running a 120 engine.
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Checked compression? My first 550k3 wouldn't behave at all if hot, ran too fast or cut out, down on power and overheating. Starting from hot was inpossible (also leaked oil like a sieve) Turned out the top piston ring was MIA on all 4 pistons, tops of the pistons were cream crackerd. half a ring was found in sump, no idea where the rest of them went (suspect very poor PO rebuild) Amasingly out of traffic it ran fine, started first or second go from cold and reached 105mph as quick as a good one. Good news was it was an easy repair, one set of good used pistons, gaskett set. Head wasn't perfect (scrored up by rings) but still toured Scotland getting fantastic mpg. Thats where the k3 rules the roost- motorway crusing A road fuel economy. Fort William accross A9? down east coast passing by Edingbourough, Perth, finally filling up at Glasgow. All on one tankfull, mates 250 superdream used over a gallon more fuel in same trip. Round town they used the same, almost to the penny when filling up.
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No I haven't but I have a tester somewhere so I'll dig it out.
Since the last carb clean mines been a good starter hot or cold and it's also oil tight, but the test might highlight some other issue.
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I remember coming across a problem on several Honda fours, not just my own but other peoples as well. The points cam is a sleeve that slides over the back plate of the advance/retard unit that holds the springs in place. There is little or no lubrication on this moving part & so can become quite 'sticky' & not always return the bobweights to the home position after the throttle has been closed after a rev-up. But be aware that if you pull off the cam from the advance/retard mechanism it's quite easy to get the cam 180 degrees out, so make a mark on both parts before you dismantle it. Lube with nothing heavier that 3-in-1 oil.
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Steve, Honda relied on the gauze in the tap as the tanks were new and hadn't had 25 years of dirty petrol in them so it didnt need to stop much crud or rust. I agree the small ones can clog fairly easy but the last batch i had you simply had tor reverse the flow into a can for a short time and it flushed said crap back out
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My carbs always clogged until I got fuel filters. Annoyingly, the needle valve would get gritty and the carbs would flood.
If you are not too worried about looks, I find the large car ones are the best because they have a good flow rate and they are cheap, so periodically, when they look really dirty, I throw them away and fit new ones.
On the subject of compression; a friend had a 550 many years ago (1987-ish) which he bought as a non runner. It had been standing for a while in the previous owners garage. When my friend got the bike going he took it for a blast and was a little too enthusiastic with the throttle. What he didn't realise, until I had to strip the engine for him, was the piston rings had become gummed up with old oil during its 'rest' and when he thrashed it they all cracked. However, I fitted new rings for him and it ran a treat after that.
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Maybe mine has a self preservation device, I had to cover 150 miles before it allowed me to ride enthusiastically.
The filter I've fitted is rather small but it's what looks like a sintered metal rather than paper element. I've found these flow very well for a small size and don't block easily, they probably don't filter all that well either but will hopefully catch anything big enough to block a jet.
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I found that the feed to the coils had a corroded connection, after cleaning that up and syncing the carbs I've only had a short test ride. It feels allot better but it doesn't pull cleanly from 5,000 up over although in 4th or lower it will still rev to at least 8,000, in 5th it runs out of steam at 80mph.
The fuel filter is still clean.
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When you say synced the carbs, I assume you mean with vacuum guages?
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No, I didn't trust cheap ones to be calibrated correctly or want to pay for expensive ones so I took a chance on a simple device off ebay, I can't link to it now as it's blocked at work but it's essentially some clear tube and some ball bearings. It's workings seemed pretty logical to me and it was quite sensitive so I'm reasonably confident that it will of done the job.
In the upper rev range it kind of splutters and surges and exhaust note goes flat.
I'm considering upgrading to a Boyer Bransden Micro Power Ignition system. On another forum the coils and the mechanical advance have both been named as possible sources and this system would replace both.
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I bought one those ones for my CB550. Worked fine.
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I've fitted a Boyer ignition kit, but I'm struggling to time it. The instructions say time to the max advance marks at 4,500 rpm. My strobe is normally clear enough to use at idle but it doesn't seem to be able to cope at that high an RPM, and also gives you a shock every time you touch a metal part of the bike once over around 3,000 which makes fine adjustments tricky. I've borrowed a bottle of tipex from work to highlight the markers, if I still can't see them I'll have to take it to someone or buy a new strobe. (although I think I need a new strobe anyway)
A quick test ride shows that it hasn't resolved the problem, it's still bogging at 5,000rpm and being inconsistent above it, although that may be down to the timing.
Cheers
Allan
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Have you checked the valve clearances ?
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I've fitted a Boyer ignition kit, but I'm struggling to time it. The instructions say time to the max advance marks at 4,500 rpm. My strobe is normally clear enough to use at idle but it doesn't seem to be able to cope at that high an RPM, and also gives you a shock every time you touch a metal part of the bike once over around 3,000 which makes fine adjustments tricky. I've borrowed a bottle of tipex from work to highlight the markers, if I still can't see them I'll have to take it to someone or buy a new strobe. (although I think I need a new strobe anyway)
A quick test ride shows that it hasn't resolved the problem, it's still bogging at 5,000rpm and being inconsistent above it, although that may be down to the timing.
Cheers
Allan
The Boyer-Bransden kit is only timed for idle...the advance & retard is electronic. As far as I remember you line up the leading edge of one of the two magnets with the edge of the centre post of the coil which has the magnetic field induced into it as the magnet passes it. To keep this as accurate as possible I disassembled the 750s advance/retard unit, discarded the bob-weights, ground off the raised bits that locate with the big not that you can use to rotate the crank, then Loctited the retaining bolt into the end of the crank. I was then able to make small adjustments using the elongated slots on the PCB backplate.
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I set the tappets when I first bought it 350 miles ago, could they cause these symptoms?
The Boyer system I've fitted is "KIT00289 Micropower ignition system for Honda "4" S.O.H.C. Motorcycles". Fitting is as you describe but it does not tell you to grind off the raised bits, timing instructions tell you to line it up the magnets with the posts at TDC then time with a strobe to max timing marks at 4,500rpm. I've ordered a new strobe as mine just wasn't clear enough and kept giving me shocks, but I'm not convinced that setting the timing will fix it.
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I seem to recall I had a similar problem before sidelining the sidecar outfit, fraid I can't say I resolved it though. Like you I tried swapping to boyer ignition but no success so problem must lie elsewhere was my conclusion. Tried another set of carbs? That was my next line of attack when I get the time.
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I don't have another set of carbs to try, I might have to lookout for a set if setting the timing doesn't sort it. I'm reluctant to throw more money at the bike though, I keep saying I'll never buy another vehicle that isn't already in regular use as they're always a pain to get sorted but I keep buying them.
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If only you lived closer...
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Had these symptoms once, was caused by multiple problems any of which can cause similar symptoms.
Engine kill switch, these are rubbish and dont stand up to the high loads that electronic ignition creates. Electronic ignition fires all 4 plugs simultaneously hence doubling the duty on those silly little switches. Bypass it or replace with something else. Ignition switches, also rubbish but not so bad as the above.
Spark plug caps must be new shiny 5k ohm jobs.
Original coils are good but can overheat when used for EI. Again they get hotter cos they are working twice as hard. Also fail twice as quick. May need an ally heatsink, mine did.
Had no end of problems when switching to EI, All sorted now, Plugs must be changed more regularly.
Also, a binding front brake can cause overheating. Idling too long, they dont like idling. Blocked main jets will cause it to bog down and feel slack, Take them off, take the float bowl off and waste 2 cans of carb or brake cleaner in every orifice you can. Remove jets, inspect, Check float height, this is another common problem, lack of fuel through poorly adjusted floats.
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http://www.sohc.co.uk/index.php?topic=2849.0 (http://www.sohc.co.uk/index.php?topic=2849.0)
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Hi,
The problem existed prior to fitting the electronic ignition.
The coils were replaced as part of the electronic ignition kit, plugs are new NGK irridiums, also tried normal NGK plugs and the caps are new NGK 5k.
Float heights are correct and loads of carb cleaner has been blasted through every orifice twice.
I've used the spray something flammable in the area vacuum leak test 3 or 4 times without any signs of leakage so I think those seals are ok, but if I have to resort to removing the carbs again I'll replace then just to be sure.
I've noticed that it's allot worse when the weather is cold so I'm working on the theory that it's running lean, I'm going to see what effect raising the needles one notch has.
If that fails I'll relay the ignition so I'll keep the ignition and kill switch control but without running the current through them.
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Has anyone got any idea how you access the needles on these carbs ?
It's a K3 and it's the PD carbs with the sync adjusters under the top covers.
I can't see how you disconnect the linkage and remove the slides so I've just put it back together for now.
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I doubt if the needles are your problem but I guess its worth a look anyway. Take off the tank, Take the tops of the carbs off, Undo the philips screw that secures the lifting arm to the rotating shaft.
Get a thin philips screwdriver down inside the slide and disconnect it from its arm. Disconnect the arm being carefull not to lose screws or the little spring and pull the slide out, its easy. If you cant get to the screws gently twist the slide and its arm till it comes off, yourll see what I mean, then pull the whole thing out and then undo the screws inside the slide. Jap screws are made of chocolate so be carefull if there a bit tight. You can do this with the carbs in place.
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I doubt if the needles are your problem but I guess its worth a look anyway. Take off the tank, Take the tops of the carbs off, Undo the philips screw that secures the lifting arm to the rotating shaft.
Get a thin philips screwdriver down inside the slide and disconnect it from its arm. Disconnect the arm being carefull not to lose screws or the little spring and pull the slide out, its easy. If you cant get to the screws gently twist the slide and its arm till it comes off, yourll see what I mean, then pull the whole thing out and then undo the screws inside the slide. Jap screws are made of chocolate so be carefull if there a bit tight. You can do this with the carbs in place.
Cheers, I'll give it a shot later in the week.
I doubt it as well but I'm getting desparate, I can't see anything wrong with the floats or lower jets and replacing the ignition system didn't really make any difference.
The significant improvement in hotter weather makes me side with it being a fueling issue.
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I set the tappets when I first bought it 350 miles ago, could they cause these symptoms?
Sure could. If they're too tight then at higher revs either the inlet or exhaust valves might not be closing completely - causing lack of compression.
Worth checking, supposing there was a spot of carbon on one of the valve seats last time you checked them, giving a false reading ? How long will it take, 30 minutes ? How long have you spent on it already ?
And yes, valve clearances close with wear, and camshafts do flex.
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clean float chamber out sounds like a dropplet of water which will be picked up and resonate at a certan flow /revs also clean out your inline fuel filter as if any water droplets in with petrol you could go 1 to 1,000 miles b4 it happens again one of those annoying probs that come and go ...........
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I hope to get some time to work on it this week end. I'm going to work in order of easyness - check fuel filter and drain carb bowls, check tappets, relay coil feed, adjust needles and re sync. Hopefully one of those steps will sort it out.
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Hi Anoyone checked the air filter? just run it with it out for a test to see effect (had a filter do this on another Honda and I could not beleive the effect was so defined, took me ages to sort). Not sure of the intake on the 550 but friend had 400/4 and put overtrousers over air box intake under seat and caused similar probs once. It'll be interesting to find out what it is, shame we can't get you more help.
Have you done a plug inspection on all cylinders when it's running hot to give you an idea of mixture?
What is the psi reading for compressions on each cylinder?
If you start it from cold, run for 30secs, switch off and touch the header pipes to see if all are similar temp tells you if they are all firing straightaway.
Check through the fuel tap to make sure there is no blockage in any passageway
BTW fuel always comes from the bottom of the tank when on reserve!! I've always run everything I've owned bike/car to as near empty as I can (what's the point having range if you don't use it) and never ever used additional filters. My theory is you might as well run anything that could be a problem out so it will never accumilate things you don't want in there. On that note, if you don't use it down to the bottom do you have a tank cleaning schedule? to get out the mythical junk.
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Hi,
I tried without the airfilter and checked the plug colours, the airfilter made little if any differance and the plugs looked good but that was some time ago and I've replaced the ignition system since. Also tried pulling the choke on when it bogged, but the choke doesn't stay on when the revs are up and in that rev range power delivary is a too bit unpredictable and rough for 1 handed riding.
I don't recall the compression readings and i can't find my notes but they were all within 5%.
I've twice found that number 4 didn't heat up imediately, but I then made a point of checking on most startups and it hasn't done it since.
The fuel flow seemed good when I let it flow into a can.
I don't normaly aim to drain a tank or have a cleaning schedule, but I have drained and rinsed out this tank.
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There are two air jet inlets at the intake part of each carb. From what I remember the left one is for the primary jets & the right one is for the main jets. When you last had the carbs off to clean did you spray carb cleaner in via these air jets to see that the fluid comes out of the relevant orifice?
http://www.google.co.uk/imgres?imgurl=http://www.dansmc.com/carbs/japanese_carbs/suzy_re5_carb.jpg&imgrefurl=http://www.dansmc.com/carbs/japanese_carbs/carb_pics.htm&usg=__vYxHYn_Xyr7XOV7XJmyNl65HUHU=&h=555&w=750&sz=55&hl=en&start=20&um=1&itbs=1&tbnid=junylZL4_PQTcM:&tbnh=104&tbnw=141&prev=/images%3Fq%3Dmotorcycle%2Bcarburetor%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26hs%3D0Q4%26sa%3DX%26rls%3Dorg.mozilla:en-GB:official%26channel%3Ds%26ndsp%3D20%26tbs%3Disch:1 (http://www.google.co.uk/imgres?imgurl=http://www.dansmc.com/carbs/japanese_carbs/suzy_re5_carb.jpg&imgrefurl=http://www.dansmc.com/carbs/japanese_carbs/carb_pics.htm&usg=__vYxHYn_Xyr7XOV7XJmyNl65HUHU=&h=555&w=750&sz=55&hl=en&start=20&um=1&itbs=1&tbnid=junylZL4_PQTcM:&tbnh=104&tbnw=141&prev=/images%3Fq%3Dmotorcycle%2Bcarburetor%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26hs%3D0Q4%26sa%3DX%26rls%3Dorg.mozilla:en-GB:official%26channel%3Ds%26ndsp%3D20%26tbs%3Disch:1)
http://www.google.co.uk/search?hl=en&client=firefox-a&hs=7ij&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&q=carburetor&aq=1&aqi=g10&aql=&oq=+carbu&gs_rfai= (http://www.google.co.uk/search?hl=en&client=firefox-a&hs=7ij&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&q=carburetor&aq=1&aqi=g10&aql=&oq=+carbu&gs_rfai=)
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Yes I sprayed carb cleaner into the air jets. I don't recall which air jet came out of the main jet/ emulsion tube area and which came out of the pilot, but the passages were clear on all carbs.
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Hi
Was it going when you got it / have you seen it run correctly?
If not it might be wise to check cam timing, think you can remove cam cover in frame on this one.
To check fuel flow fully you need to remove a float bowl (go for furthest from supply pipe) and turn tap on, it should flow reasonably fast into this say an egg cup ish in 5secs (is an egg cup an official scale in bike mechanics!!).
Looks like you've checked carbs quite well and if two sets of ignition give the same results that seems to get them off the hook.
Seems like you've got a few of us scratching our heads on this one so hopefully somone can come up with a reason for it.
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You could be onto something there, no I have never seen it run correctly. It ran when I bought it but it was very flat and took ages for the revs to build, correcting the ignition timing made it more responsive and that's when I discovered the current issue. I'll check the manual for cam timing instructions.
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I've seen quite a few things run with "curious" cam timing both car and bike and it can be used as a method of changing power curve particularly on twin cam in which it alters the valve overlap period but you'd really have to have good reason and knowledge to vary from stock.
It'll be interesting to see if yours is correct or not, but if not i'd guess at cam timed early as being slightly late I would have thought it would give a bit of a screamer with poor starting.
If you don't find anything we'll have to think harder!
Cheers.
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This is kind of on hold as I've discovered the front brake needs servicing (other thread).
I've dropped the needle clips to the centre notch but haven't had an opportunity to test it out. (needles were moved before checking cam timing as I could only find 2 elastic bands and needed 4 to hold the rockers)
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As far as refitting the cam cover is concerned, just back off all the tappet adjusters completely, and this will give you sufficient clearance. Get it wrong & you could end up bending a valve...i've seen it done.
I had a thought over the weekend about the situation that you have on your engine. Does the automatic advance & retard mechanism work? You may well need to remove the points in order to get a firm enough grip on the points cam. If the cam was seized in the fully advanced position, it would make it difficult to start & to not rev properly. If it is seized, make a mark on both the cam & the A/R units back plate, as it's easy to get the cam 180 degrees out. Check the springs have sufficient strength in them to return the weights back to the rest position...if they've been stuck in the advanced position, it may well have stretched the springs.
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I've removed the advance/retard unit as part of the fitting of a Boyer ignition kit.
Cheers
Allan
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I'll bet you'll be glad when you get it fixed.
When it stops is it really roasting hot or more normal range? as dropping the neadles will make it hotter ordinarily.
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temp seems normal to me, but i've only got a monkey bike to compare it to. I'm never sure of the needle terminology, I've lowered the clip to the mid notch thereby raising it one notch making it richer.
I can't wait to get it sorted!
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Richening the needles by one notch has had a positive effect, it's still has quite a bad flat spot but it's allot better than it was. I'm now going to put some miles on it to get a better feel for it before trying to fine tune it further with a larger main or another notch on the needles.
Thanks for all the help I've received on this thread.
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Are you getting some miles onto it now?
I guess if it still struggles with thottles wide open then you are looking at main-jets as the needle position primarily adjusts the mid range only once the main jet size is correct.
It's interesting why it's so far out, if that is the cause.
Good luck with it anyway.
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Just got back from a holiday so havent ridden it since my last post, I'll hopefully get out on it this week.
The only none standard part I'm aware of is the motad pipe. I've read that they don't require a rejet but maybe it's became less restrictive with age, it does have some surface corrosion so I'm guessing it's been fitted for a while.
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Yep they seem quite a good match for original, got one on a CBX750 and it runs fine on completely original jetting right from low to high so their claims appear to be fair.
It's always good if you can find the real reason for any problems to help avoid them happening again.