Honda-SOHC
SOHC.co.uk Forums => Project Board => Topic started by: CMXCol on November 02, 2024, 02:30:10 PM
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Hi All
I have a strange problem I have never encountered before.
Having just rebuilt the engine crankcase and top end something does not make sense to me.
Here it is.
Engine turnns on crank with a socket wrench OK.
All gears work neutral can be attained.
When the engine turns the clutch basket turns with it with or wothout the clutch plates inserted.
If I try to turn the engine with the kickstarter it is locked.
If I remove the basket the kick start mechanism/shaft turns fine and turns the drive gear that connects to the oil pump which turns and would if fitted connect to the clutch basket gear.
This also happens if I fit the clutch cover and bearing with the push pin fitted
All clutch plates are within spec thickness.
Seems odd?
Any ideas?
Anyone come across this before?
Is something going wrong in the gear box?
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I have not worked on these.
But, it's OK with the kick-start cover off?
But locks up when it is refitted?
If this is correct,
I suggest you check the kick-start mechanism and return system
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No it doesn't work with the cranks case off either.
If I turn the shaft the clutch basket goes on to via splines with its nut it turns freely but it doent turn the engine it just spins.
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It sounds like you have disturbed the timing of the kick start on the shaft.
Fit the shaft assembly into the engine casing making sure spring hole at the beginner end faces upwards and the oil hole is visible in its casting recess. Place the return spring over the shaft and engage the inner tang of the spring in the cross drilling in the shaft. Once engaged fit the retaining collar between the spring and the shaft.
Turn the spring free end until you can hook it over the anchor pin. Fit the plain washer against the retaining collar and secure it with a circlip (a new one).
Place the spring seat and spring over the protruding end of the shaft. Fit the decompressor cam ENSURING the punch marks on the cam and shaft are aligned.
If you have removed the clutch make sure you have replaced everything in the correct sequence especially the locking washer that has the word OUTSIDE stamped on it, this goes under the clutch centre but.
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That's the inner end NOT the beginner end, that's spell check for you!
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Thanks for that howevere I'm not so sure the kick start has a problem at all .
For some reason I can't post videos it crashes this site for me.
So here are two pictures showing the kickstart will swing when the kicker is pushed without the basket on it locks it only locks when the basket is on.
But the engine turns when the basket is on.
I can get gears when the basket is on
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And another showing it will swing alright?
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With the basket on it locks the kickstarter will not move.
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I can’t host videos Colin as it just gobbles up the storage.
You can embed YouTube videos though which is the preferred solution.
Steve
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Have you tried the kick-start with just the clutch basket ? No plates installed.
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Have you had the engine completely apart at all? Has the bike been running normally and did the Kickstarter problem just happen out of the blue or has there been other symptoms leading up to this problem?
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Ok, so reading the first post again you say you've had the engine apart. When you reassembled it did you ensure the two alignment marks on the Kickstarter shaft were aligned. There is one on the ratchet and one on the shaft, if they are not aligned it will lock up. These two dots are in addition to the two dots on the decompressor cam I mentioned in my earlier post.
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If you are not sure the only way to tell is to split the crankcase as these two alignment marks sit on the Kickstarter shaft that is inside the crankcase.
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Thanks for the reply.
I am beginning to suspect the lock up is occuring in the gearbox somewhere this will invlolve a complete strip down of the engine again.
I did rebuild the crankcase/gearbox.
Just seems so bizzare though that the engine "will" change gear when turning which tends ot suggest it's not the gearbox.
The clutch turns with the engine as well.
Also it still locks up with no plates in the basket.
It is not on the crank side either the valves are lifting and closing correctly on TDC the cam chain is not stuck it turns over smoothly.
Just cannot figure out what this is.
Rebuilt quite a few engines and never ever had this issue before.
I'll go for the complete strip down that's the only way I would find anything wrong I think.
The only possibility I can think of is there's a woodruff key stripped on a gear wheel and it's spinning or jammed somewhere on the shaft that holds the clutch that's the only possible thing I can think of.
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Laverda Dave
Yes agreed I'm sure all the shaft dots were aligned correcty.
I am going to have to strip it all down again I think only way to check things here.
Thanks for the replies.
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Ordinarily, with the plates removed from clutch, then the gearbox is removed from equation as with the drive to gearbox now detached.
Date knows more about layout than me specifically for this engine though.
Generally, design of bikes has kick onto clutch basket and then to crank, not via gearbox. That so you can kick them over in gear while pulling clutch lever to start, meaning you don't have to select neutral.
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Yes you have "primary kick" where you can pull clutch in and start engine or "secondary kick" where if you pull the clutch in the kickstart does nothing.
The crank turns the basket on a bush on the shaft, there should be thrust between clutch basket and clutch inner, without this the gearbox locks, try looking at a parts diagram on cmsnl to see where all the parts go, it is possible in some Hondas to fit a bush in a gear the wrong way round which will also lock the box when thongs tightened.
This is one of those where if its in front of you it may be obvious but long distance over the net is very difficult
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OK
Fixed it.
The issue was very difficult to pin down I had to rebuild the gearbox twice to find it.
On the balancing weight end of the clutch shaft opposite the clutch there is a needle roller bearing it has a thrust washer, (red arrow) the bearing outer shell also has a hole which locates on a dowel pin (blue arrow) in the bearing mount.
The thrust washer pushes into a thin housing, a thin recess, just before the bearing mount with the dowel.
If this thrust washer is not seated correctly even with the casings closed it can cause the bearing to not quite seat correctly now that doesn't expose itself until the engine is put in gear, any gear, the very slight misalignment causes the gear train to lock I noticed even when the gear selector was in the neutral position it was still locked in gear, the drive sprocket wouldn't even turn making it impossible to turn with the kick start in neutral once the gearbox locked.
Picture of offending items "arrowed" attached, just one little washer caused all of that grief.
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Well done
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One of those " gotcha you barsteward" moments
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Pretty impressive that you found the cause of the problem, well done.
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Good news and a simple fix in the end with nothing broken or seized.