Honda-SOHC
SOHC.co.uk Forums => CB650 => Topic started by: M0WBY on October 14, 2012, 09:36:09 AM
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Hi
OK guys... I have been reading up on issues relating to my Layla (81 CB650C US import). Basically it only runs on choke and only on two cylinders!
I am going to go and buy a compression tester on monday to test the compression. It is not running on cylinders 3 and 4. I am suspecting that, since it only has 25K miles, and due to it standing since 2003 that the piston rings are stuck. The received wisdom as far I can tell is to not worry about it and get a few miles on the clock and they will free up of themselves.
The only problem is I need to get it running right first. All indications are that I have carb issues that need sorting! Now my bike had VB44A carbs but two of them were scrap. I don't know what was in them but it was nasty! Like black paint stripper! I have a set of VB54A carbs off a french CB650 on it at the moment. But the jets and air screws are off a set of VB54B carbs. The jets are #90 they are smaller that the ones from the VB44A as originally fitted which were #120. I may have a go with the VB54B carbs and see what that does. I have a problem though. The VB54A and VB54B carbs both have two air pipes on them that I don't know what they are for! Or where they should connect to! Are they just harmless air vents or am I missing a trick here or what?
http://www.flickr.com/photos/discoclover/sets/72157631764843253/
I have tried winding out the air screws until they are nearly falling out and it still won't run with the choke off!
Help!
Cheers
John
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Hi
My compressions readings on a warme up engine (well running on 3 cyl with choke for 10 mins) are...
cyl 1 left 120PSI
cyl 2 left inner 120PSI
cyl 3 right inner 120PSI
cyl 4 right (not firing) 110PSI
I tried to down another test with a tea spoon of oil added but I could not find a way to get it into the middle cylinders. I need a pipette or something!
I have to admit that my 12mm adapter was not very good so the results are not quite what they should be.
So what do I know now... I am confused!
Help!
Cheers
John
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Hi John
The internet is your friend (of course you may have already found these...)
Compression:
http://www.hondacb650.com/viewtopic.php?f=4&t=1369
http://forums.sohc4.net/index.php?topic=15840.0
so it seems that can be left for now at least.
With the basic stuff like valve clearances and ignition timing checked you will have to get your carbs sorted. You are off to a difficult start with the hybrid affair you have got. Something must connect to those pipes you showed because they have clips on them. Here's a manual:
http://cosky0.tripod.com/
but not the same carbs as yours though.
Promise of other manuals here but you'll need to join the group: http://autos.groups.yahoo.com/group/Honda_CB650/?yguid=178049669
I reckon it will continue to cough and splutter until you strip, clean, service and adjust them properly.
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More info about those mystery tubes, possibly. May be they just vent:
http://forums.sohc4.net/index.php?topic=100351.95
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slow running jets blocked is my bet
pete
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Hi
They are between 1 and 2 carbs and 3 and 4 carbs. They seem to be just vents...
I have had the carbs off and checked every thing even again. Replaced all the o rings again. There does not seem to be any air leaks.
I took the air screws out and put a tube over their hole and blew out the slow running jets but they all seemed to be clear.
It has intermittent running on cyl 3 and will not run at all on cyl 4. It only runs on 3 when on full choke. It will now tick over, sort of, off choke but as soon as you try and rev it up it dies as it is only running on two cylinders. It is sparking I checked that and the timing. I checked the rocker gaps.
I think I am going to have to pull the top end off the engine and see what is going on... :-(
Booooo!
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Hi Mowby,
Not that I have done much work on the CB650 but they can not be much different to all the other fours.The things I would do is first set everything to the book air screws etc.Before trying to start the engine check all the plugs are sparking as you crank her over by the crankshaft.Point gaps are correct open carb bowel screws to make sure fuel flows out freely from all four.The compression to me sounds OK and if she only runs on choke definitely sounds to me fuel starvation.Open each bowel screw turn the fuel on and if no steady flow open the tank filler cap and if flow increases you now the filler cap vent is blocked.All the time you are messing with fuel lots of rag and no smoking please.Once you determine all four spark and all plugs are getting wet she should start OK.Once all four headers warm up then you can fine tune with balance and air screws adjust.After all this and no go I would then start to think about naff valves etc.I like the sound of you and only wished I lived near to you as I would have liked to help you out I could do with the company.Do not be to hasty to strip her down yet.With these old classics you must consider Rome was not built in a day some guys I have met have taken at least two years to get perfect.Keep your chin up you will get there.The carbs I sent you did you strip them,use carb cleaner everywhere blow compressed air through every orifice and reassemble to the best of your knowledge.I do not mean to underestimate your cababilities but I had to do mine several times as I took for granted that a shop that ultra sound cleaned them was it.No it was not.I wish you luck and keep going as I said you will get there and when you do you will think I fracking sorted that.
All the best
Bitsa
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As Bitsa says, be careful of the fire risk and if you are getting petrol all over the place then do it outside as you only have to save the bike and not your garage as well.
Just some basics to add to the others: switch the plugs about to make sure that the problem isn't one or two of them.
Compressions sound as if they would be ok to run without any particular problems.
If you can get it running at a fast idle then blow some petrol down the #4 carb (you can just use a long thin tube in you mouth to suck a small amount up and blow it into the carb mouth) to see if it will actually run on that cylinder, this would verify the carb if it did.
Check to see if the valves are opening on number 4 as well.
As Bitsa says I wouldn't pull it apart just yet as it may well be outside the engine and you'll do the other work for nothing.
Try running it in the dark to see if you have any sprks coming out the HT leads and not reaching the plug when in normal running configuration, specifically where the plug leads go past the head castings.
Try switching the 1 and 4 HT leads over (they are both fired at the same time) to see if #1 stops and #4 starts.
Let us know how you get on.
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Hi
The float heights on the CV (VB44 and 54) carbs are not adjustable oddjob.
I have fuel in all the carbs so I don't think the petrol tap could be a the issue but I am not ruling it out. I will do the test Bitsa suggested and/or remove and clean it out anyway just to take it out of the equation.
I suspect fuel starvation is part of my problem but I think there is another issue as well.
I have no garage so I have to do all my spannering outside but I am looking at renting a garage from a friend just as soon as he gets a roof on it!
I am going to investigate the sparking side of things again. On the 650 it has an electronic ignition as per http://www.jasonkent.ca/manuals/79%20CB650%20Service%20017.pdf (which is 79 manual - but the manual is the same for mine for this section). I will perform all the tests starting at the top and working my way down to see if I have missed something. It has new plugs so they should be OK but I can swap them over it is no big issue. I may replace the HT leads whilst I am at it.
I am thinking weak spark. It sparks at the plug on cyl 4 when I took it out and tested it but what it is doing under compression is another matter! I am thinking perhaps a pulsar or CDI unt is going bad or even a coil? But it is sparking fine on the other cyl, and it uses the same system for cyl 1 and 4, so the only thing it should be if it is a weak spark is the HT lead surely? Is there any reason why I can't just chop up and use a 7mm silicone car HT lead?
I just wish I had someone local who could look over it and give an alternative perspective on things.
Cheers
John
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Hi
Had a good session on the bike today checked the ignition system working from the spark plugs back. I checked the timing and it is spot on. Replaced the HT leads anyway. I can defo say it is not for lack of spark that it is not running on cyl 4. Also cyl 3 is still only running intermittently and does not really kick in unless it is either on full choke or when warmed up only really kicks in past 5K rpm. So I think I can rule out the ignition system! Straws have all been clutched at and been found wanting! It is not the ignition that is to blame!
I double treble checked the tappets again. I can confirm they are all correct. I checked that they were turning over with the covers off and can say that this side of the engine seems to be pukka!
So I have two options. Either it is a sticky valve and/or piston rings on cyl 4 and it also has a bit of fuel starvation.
So I checked the fuel side of things. I noticed that the fuel pipe was a bit too long and went upwards after it left the tap and the fuel delivery is not strong enough as it has only gravity allowing the petrol to flow. The slightest uphill bit in the pipe effectively slows the flow down to a dribble! So I shortened the pipe as much as I could. On my American VB44 carbs they have this part that runs off the vacuum in cyl 2 by an attachment screwed into the balancing screw hole. This has a pipe to something that is attached to the carb rail. This has one tube to the petcock and another that attached to the petrol intake on the carb and another that vents to fresh air. There now follows some more straw clutching... :o
I am wondering if the american petcock is the wrong one for my carb system. The CB650 night hawk has a vacuum operated petcock http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221129886560&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en. I am thinking I may need a vacuum operated petcock on mine. That one of the pipes could possibly be for a vacuum system all thought neither seems to suck or blow as far as I can tell... Bloody things doing my swede... thoughts please gents! I am thinking I may have to try reinstating the american system and block off the two vent pipes just to see if that is the issue causing my fuel starvation issues!
Anyway whilst it still is not running right it is better than it was. It is not back firing so much or coughing as much as it did! When fully warmed up it will run at about 6-7K rpm without the choke but it needs the choke 1/4 out to tick over and run below 5K rpm. No matter what I do it won't run at all on cyl 4 despite having a good spark. The plug comes out wet suggesting that fuel is getting through. I think I will have to rip this engine apart! That is the way I am leaning towards.
Ho hum...
Cheers lads for reading my moaning!
John
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Is the plug wet with petrol or oil?
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Petrol
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Hi
As long as it does not have broken piston rings then I am hoping a good hone and a new set of rings ought to sort it out plus some new valves and/or valve seats.
I think this is why matey boy got shot in the first place... came in only running on two cylinders. Then sat around for a decade. Then he finally thought about doing something with it realised it was shagged and thought I wonder how I can get myself out of this hole. So he got a bent MOT and put it on the bay carefully managing to not mention the bit about it needed a rebuild and blaming the poor running on the carbs!
Oh well you gotta make mistakes to learn from them!
Ce la vie! I think a few beers to drown my sorrows is in order!
But I still want to get to the bottom of the fuel starvation thing!
Cheers
John
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Hi oddjob,
I used the whole bank of VB54a carbs so they have the same float levels in all of them. The only thing that I needed for them off the bank of VB54b carbs were the jets and air screws. I put the old VB44a carbs in my parts bin should I need bits off them in the future (read about 10 years down the road they will be on ebay because I can't remember why I ever kept them!) :D
The VB54a carbs I got off Bitsa where superb quality and look as if they are practically brand new! Which is quite a feat for a set of 30 year old carbs!
I don't know if the float levels are different between the 3 sets or not so I did not chance it.
Cheers
John
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Hi
Got it running real sweet on 3 cylinders! I tought well seeing as I will have to rebuild it anyway I thought to hell with it and I rode it around the block over and over again until the fuel starvation cleared! Anyone fancy a triple?
Going to pull this engine apart and see what it is doing! I reckon the head gasket is shot on number 4 cylinder. The symptoms are lack of compression on one cylinder, there is a spark but it just keep getting the plug wet and not firing, and it is chucking oil out the breather pipe.
Nuts!
John
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Hi
Took the head off tonight. Bit disappointing really I was hoping for something that I could blame the issue with cyl 4 on but I did not. I did notice I was not the first person to go in there. It had the o ring on the left side replaced. It was a bit of a cheap skate job as everything has sillycunt sealer as they obviously used the old gaskets and wanted to make sure they sealed! Which they did not as it happens.
The bores seem to be in good order you can still see the machining marks from when they were bored out or maybe it has had the bores honed. The head gasket was fine. Nothing to report. From visual inspection the valves seemed to be seating. There was no scoring of the bores by the piston rings that I could see.
Early days yet. I may get the head pressure tested. Seeing as I am in there I may get the valve seals replaced. Unless they find something i will leave the valves alone. Or possibly get the seats re-cut and new valves and seals if there is any question regarding them!
Next will be pulling the barrels off and seeing what shape the piston rings are in.
Ho hum...
Cheers
John
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Hi
Going to remove the barrels when I get a minute will have a look. I hope this is my issue. A new set of rings are in order I reckon! I have removed pistons on cars before but never on a mutliple cylinder bike. With a car you do one at a time. This will be a challenge to get all four in! I could do with some tips on getting the barrels back on.
Also on cars (well you can sometimes get away with it if there was no overheating and the head is flat) you have to have the head skimmed. I am assuming it is the same on a motorcycle?
Where is best to get the rings from? My local engineering shop or order them from David Silver?
Cheers
John
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Mowby.
In all my experience I have always decoked valves and ground them in and new guide seals whether they need it or not. I have never had to replace the guides or skim the head perhaps I was lucky .As for the cylinders remove one ring place in bore and measure the gap.If out of speck new rings and I would only use Honda are in order providing the right speck is attained otherwise its a re bore.Again never had to have that done yet.In my mechanic days loads but that was on the small Honda's where the Muppet's never kept the oil changed.For putting the cylinders back on it is not too hard as the bores are tapered I ususally start with the middle 2 sliding them in until you can only just see the piston pin slowly turn crank(the cylinder will move) as the outside 2 come up to meet cylinder guide them in .I use my finger nails or a small driver to push the rings in.If new rings are fine I do usually slightly hone the cylinders enough just to remove the smooth surface gives the rings something to bed into.Also I always test the valves after grinding by filling up intake side with petrol if they are not sealed right you will see it weep through.Make sure you are in a ventilated area and no flames around you when doing this as you probably all ready know.Wish you luck
Cheers
Bitsa
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You will probably find that rings are only available from Honda as the 650 was not that popular, definately while the head is off change the stem seals and maybe lap the valves
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Right guys,
The 650 not very popular? You are not kidding if they all needed a rebuild after 26K miles! Crap is all I can say! Unless somebody changed the Speedometer at some stage!
All the rings were complete. I have measured the rings and what I found was a revelation. I thought cyl 4 would be the worst but apparently not! The HBOL says Nominal ring gap for top and middle 0.10-0.30mm Oil control 0.30-0.90mm
Wear limit top and second 0.7mm Oil control 1.1.
My measurements were
Cyl 1 T & M 0.33mm Oc 0.95mm
Cyl 2 T & M 0.35mm Oc 0.75mm
Cyl 3 T & M 0.85mm Oc 0.94mm
Cyl 4 T & M 0.38mm Oc 0.94mm
Cyl 3 may needs a rebore.
The piston ring grooves were fine.
Cyl 1 minimal carbon in the grooves
Cyl 2 clean as a vicars underwear
Cyl 3 Ye gods!!! More carbon than you can throw a stick at!
Cyl 4 A bit of carbon
So in concluesion it is cyl 3 that is shagged so I am no better off knowing why it was not firing on cyl 4!
David Silver has original Honda rings in Std size. He only has 2 sets of 0.25 over size and none 0.50 over size!
So if I end up getting it rebored I am guessing the engineering shop will tell me which size pistons and rings I will need and I hope they are not 0.50 over!
As soon as this thing is rebuilt I will run it in and then get shot of it before it needs reboring again!
Nah only joking this thing is with me for the longhaul! Grr even if it does need rebuilding every 3 years! ROFL
Poor old girl http://www.flickr.com/photos/discoclover/8105888596/in/photostream http://www.flickr.com/photos/discoclover/8105869705/in/photostream
Got a beer to drown my sorrows feeling it is not the only one I will be having tonight!
Cheers
John
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It just doesn't look like there is anything there that would stop it running on those cylinders to me, maybe a bit underpowered or some compromise but you'd expect it to be firing at least.
I've seen engines that are far far in excess of this and although a bit ropey they still run and not bad either, think you are really looking at fueling/igniton as the original problem.
Silicon gasket can be the death of these motors as any loose bits can often be bigger than an oil supply route and very often trash the top end of the motor fom oil starvation.
As Bitsa says, the bores have quite a nice taper at the base so feeding the pistons/rings in there is not a bad job, just take it slowly and you'll feel them go in quite easily usually.
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I would suggest an accurate bore measurement in several places to see if tapered, oval or out of spec and work from there.
Cylinder bore dial gauge is best---I got one but it might be too far to Gloucester!
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Hi guys,
Thanks for explaining things oddjob... Please excuse the questions just trying to clarify things in my head! I was a little confused by things and over what exactly I was measuring! I had to go back to the manual and do some revision! ::) I have to put my hands up and confess that I have not had to look at piston ring gaps and bores in a long time! I was using the rings with the cylinder they came off. I will order a new set and see how they compare. I think it is the rings that are worn on Cyl 3. Probably was due to the carb issues I am guessing. One thing I noticed the online manuals have you measuring the rings at the bottom of the bore as opposed to the top in HBOL. Measuring them at the bottom makes more sense to me.
I am hoping that I can just get away with a hone of the bores.
It says in the manual that each ring is marked so you can tell which side is up and also that one should be marked with a T to denote top ring. I have looked at mine and none are marked with a T! In fact the only difference is that each ringset have one ring with the marks 'R N' and the other is just marked 'R'. You are meant to be able to tell which is Top and which is second as second ring is tapered but I can't see any difference! They all look the same to me!
I am hoping the new ones will be marked with a T so I can tell the difference!!!
Cheers
John
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Hi oddjob,
OK so they are different colours when new that helps...
I am confused now about end gaps and worn rings! I understand measuring the three points to see how the bore is worn. But how does one tell you if the rings are worn and need replacing?
With mine it was obvious because with Cyl 3 rings it was really easy to compress and put them in the bores. The others were a lot harder. The other three seemed to have more spring to them. Is this how one tells they are worn? Seems a bit subjective to me... Still if you are in there you must have suspicions and you would be a fool to pull it all part and not change the rings as part of the course!
But if you had all fours sets that were all as bad surely they would all feel the same and unless you compared them against new ones you would never know! Does this make sense?
Cheers
John
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Yes you are making sense.
Without a way to measure the bores independently (micrometer instead of using a new ring) I suppose you cannot tell. However as Oddjob suggests, one new ring set is unlikely to go to waste but while you are waiting you could:
1) choose one bore and measure all ring sets against it (bore is constant) so you get some idea of how the rings compare
2) use the "best" set of rings to measure all your bores (ring set is constant)
Then you have some comparable numbers for both.
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But measuring different ring sets on the same bore won't make any difference as they will all have the same gap because that is decided by the wear on the bore surely? Or am I being stupid? Do you see why I am struggling to get my head around it?
Otherwise the only test is the spingyness of the ring and whether it stays compressed in the ring groove?
Perhaps I am thinking about it too much!
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Thinking is good. I am only thinking that if a ring itself is worn then it won't be as wide as a new one and its end gap when inserted into a bore will be larger. I would also imagine a narrower ring would be less "springy". (Note I am choosing my words carefully - I'm not talking about the ring clearance in the piston groove - then I would talk about a ring being "thinner" - just saying).
Since ring wear has been cited (if your bike ran lean for any length of time) then its worth measuring, at least comparatively for now across the sets you have. Likewise the bores - if they are all similar then chances are your barrels are good.
When you get a new ring set you will have absolute measurements and you will know whether you need more.
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that if a ring itself is worn then it won't be as wide as a new one and its end gap when inserted into a bore will be larger
Why? The ring does not wear on the ends surely? Surly how worn the bore is determines the end gap. Larger end gap = more wear on the bore.
It seems the main issue is how willing they are to uncompress in the bore the rings are. This I would guess is determined by the carbon in the ring gap holding the piston ring closed and allowing compressive gasses down the side of the rings?
I am speculating that the hardness of the steel has something to do with this as well because a less springy ring are easier to compress and might allow gasses past?
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that if a ring itself is worn then it won't be as wide as a new one and its end gap when inserted into a bore will be larger
Why? The ring does not wear on the ends surely? Surly how worn the bore is determines the end gap. Larger end gap = more wear on the bore.
No it wears on the edges, gets narrower and has to expand more to reach the bore. (btw I wasn't trying to suggest it gets "shorter")
As Oddjob says, your measurements at the moment will combine ring and bore wear, until you get a new ring set. Hence I was suggesting eliminating one of those and then the other... just to see a bit more how things are.
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A piston ring wears in two ways:-
(1) They actualy move up and down in the ring groove as the piston changes direction at top and bottom of stoke and strange though it is the steel ring wears more than the alloy piston.
(2) The friction between ring and bore will wear both the bore and the outside of the ring so that the ring has to expand more to touch the bore hence the ring gap gets bigger.
Now in 30+ years(a lot of those in Honda dealers) i have rebored a lot of Hondas but 99.99% of those rebored were dur to siezures not wear! I can only remember a PF 50 years agp that actually had a wear rindge at the top.
What Tom was saying is if you use only one ring on all the bores you are getting atrue indication of bore wear as all the rings will be worn slightly different
Also if you measured all the rings in only one bore yoou would be able to see if one set was a lot more worn than the others
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:-[ The penny has dropped... I can't believe I was so dumb! It is obvious now you three have pointed it out!
Hangs head in shame!
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John
I (and I'll wager I speak for others) think your posts are great. Your enthusiasm shines through... I don't know if you've worked on these bikes much in the past but I'm no expert myself and we all have to start somewhere.
When I was 18 I bought a 400/4 unseen (well my brother had seen it at the dealers). It was only three years old but already had koni shocks (may be an improvement measure?), non-standard handlebar grips, the kickstart sometimes didn't engage, the clutch snagged and (as I discovered) the cam chain tensioner bolt was snapped off.
To pick up the bike I trained it to a then dingy Liverpool St station with the CB175 I was trading in lashed in the guards van (that was for free as well). Found my way to Acton and then rode the 400 back to Norfolk. Once I found out about the cam bolt I remonstrated with the dealer - to no avail of course. I then succeeded in snapping an easy-out in there. I reckoned I'd sell it and get a Suzuki GT380. As good as those bikes probably are that was a case of "shame on me". I missed a call to my advert and then thought sod it - I'll strip the bugger down.
Over the Christmas holidays I took it apart on an old kitchen table in the garage, took the crankcase back to university and to an engineering shop my dad used (in fact A L Carter Engineering Rear of 7 Chiswick High Road is still listed on 192 etc) and it cost me 40 quid (king's ransom to a student then) but the job was good. A large plug tapped in there and then drilled to the original bolt size.
Back home on the train, put the engine back together over a weekend and then ride it back to London. Don't know if kids/students would do that kind of thing these days.... anyway the kickstart was fixed, the clutch action was smooth and it rode great. That was until it was nicked two years later - NGH276P is hot by the way.
But I digress. Layla will rise and ride again. Your top-end strip is a good idea. I'd suggest grinding the valves in and fitting new guide oil seals while its out. Clean up the ports a bit... your new rings may be... getting the barrels back on is a piece of p1ss. Sort your carbs (you got them from bitsa? I'm sure he wouldn't flog you rubbish but nonetheless they may need a proper ultrasonic clean out - ok I'm at the limit of my knowledge when it comes to carbs) and we await your piglet-stylee videos.
In the mean time keep up the good work and do please continue to post your travails.
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Mowby,
I introduced myself on this site because as an ex mechanic who worked for Paul Smart I had forgotten so much stuff that I started to listen to advice from all over the world.As time went on it started to flood back to me and in the end I went with what I started to remember and especially ignored all the hype from the USA they are so excitable.What I did learn from Honda UK was that regardless of the models things did not change much.Part numbers were mostly all the the same and after reading super stuff from all over the world I found that I had had enough and went with what I remembered and guess what after fracking about with carbs for best part of two years I went for what I know.My bike now runs perfect ticks over great and am well impressed after 38 years its just as I remembered.I put in today a gell battery after she stood for 3 months and she burst into life after two arm kicks.Like I said go with what you know too much info fracks you up.There is no body that knows more than Honda does and I will get some flak for that statement but most of the guys here will give you info that in the past has worked for them does not mean it will cure your problems.Yes with the 750 you have to take the engine out right pain in the butt but my 1300 xjr to change the fork oil I have to dismantle the whole front end and don't start me on greasing the swing arm.Give me the old Honda designs any day,Persevere and you will be a happy chappie at the end of the day.
Keep your chin up
Cheers
Bitsa
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Hi
I have had a lot of bikes in my time! But I can #@%$ you there. I had a GT380 and a Honda 400/4! I was really into my two strokes and I got the 380 as a fixer upper but I sold it on before I could do anything with it. I have had loads of the Suzuki GT range. All of them except the 185 in fact... oh and the X5 (the 200 twin) but my next door neighbour had one if that counts! I had a fleet of GT250's at one stage rotating between them which enabled me to sort the problems on the next one whilst thrashing the life out of which ever was running at the time. I had a mechanic friend who also had a GT250 and we were in a constant competition to see who could get theirs tricked up and running the best! Of all my GT's I have fondest memories of the GT750 (EGJ 156T)! I was doing my engineering apprenticeship at the time and life was pretty good! But my time with the GT550 is a close second as it was a good bike, until it stopped charging, and broke down with a flat battery one day! I can remember the day vividly. I was on my way to work in the middle of a particularly harsh winter! I had no money on me to phone from the call box (no mobile phones in those days!) for my uncle to come rescue me. So I had to walk the 5 miles home. The 400/4 I can't remember much about except it was a real hack. Can't even remember how long I had it or why I sold it. All I can remember is riding it to Stratford upon Avon one day.
I am hoping to drop my cylinders off at the engineering shop today if I get time. I am off to Telford this morning to fetch a new 4 into 1 exhaust that I bought off ebay. The guy does not know much about it only that it is for a CB650 and it is made in England. I shall quiz him a bit more about it when I get there. Unfortunately when I took my exhaust pipes off I realised I had a stress fracture in one of the mufflers and taking them off was the final straw and it handed in it's notice. So the 4 into 1 will have to do until I can afford to get a replacement. I think finding one that is any good will be my problem.
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I now have a new motad M6h 4 into 1 exhaust. Just got to get my hands on the fixtures and fittings and suss out which down pipe goes where! £264 new I go for a lot less than half that!
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Motad exhausts are normally numbered where the downpipes enter the silencer, saves a lot of head scratching! Also on your original problem IE running on three, check for bent valve on that cyl as i had similar problems with my 550.
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Hi
Yes I contacted Motad and the stupid sales guy reckoned that they don't supply the head rings with their motad exhausts and to use the original Honda exhaust pipe collars! Despite my pointing out that the instruction manual he sent me says that the M6H comes supplied with 4 no. 21 head rings! He quoted me £7 for the bracket but when I said I would willing pay the £7 if I new how to order said item online from his website. I am still waiting to find out how I do this...
At least the instruction manual helped me to work out which pipe goes where. I would of been able to work it out if I offered it up to the bike but as the cylinder head and cylinders are off it at the moment I was kinda stabbing in the dark! Also I don't have the bracket either which I can see I will end up making myself.
Bad news on the honing is the engineering shop are no longer offering that service or rebores either anymore as it takes too much time for a relatively low return. But my local bike shop were able to point me towards a company in Wolverhampton that I can go to. The bike shop don't usually offer rebores and stuff anymore either as it is cheaper in the long run to throw the old cylinders away and fit new ones! I could not get my breath! Has this society really become such a throw away society that they don't bother trying to repair stuff anymore!
Gahh!!!!
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Hi
On a separate note I have left the head standing upside down with some degreaser fluid in it. Unfortunately on Cyl 4 it has mostly leaked out through the valve seats after 4 hours so it looks like I can confirm that the valves may not be seating correctly on Cyl 4. Which may be the reason why it was not running on Cyl 4. But I am reserving judgement until I get the valves out and see what is going on for sure.
Cheers
John
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Hi
Well I dropped of my cylinder block at PJ motorcycle engineering in the Hampton's (Wolvehampton LOL makes it sound posh). They wanted one of the pistons with new rings on it to make sure that the honing is correct.
I figured that I was only a few miles away from the Motad factory in Walsall. So I decided to visit and see if I could not order my exhaust collars and fixing kit including bracket. Fair play the guy was a lot more compus mentus in person and I soon secured required items and left a happy bunny!
My mate who is a bit of a dab hand at welding reckons he will be able to repair my old exhaust but it will need chroming again afterwards!
I will get there!
Cheers
John