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1975 M151 Kick-Starter Chatter


srm
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I just got this bike and didn't notice the chatter the first week.  Now I notice it alot.  The kick-starter seems to chatter all the time.

When I press lightly on the top it will stop.  I tried to move it forward a bit, but it did not help.  I couldn't find anything in the forums or

on line?  Any suggestions to why?  Do I just have to put up with it while I ride?  Thanks for any help.

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Depends on what you mean by chatter

 

Do you mean loose on the spline so that it is vibrating, or that the swivel (that you put your foot on) is loose on the shaft and is vibrating / chattering. This is normal wear and tear

 

If it's loose on the spline it can be because the bottom of the slot that pinches together has closed up so that when the bolt is tightened it doesn't clamp up properly. You can saw a piece out of the slot on the kickstart to cure that so that it clamps up tight again.

 

If the swivel joint is worn it can be re-bushed.

 

Or do you mean that the kickstart ratchet inside the gearbox is remaining partially engaged and chattering which you're stopping by pushing the kickstart return position fully home by applying pressure.

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Depends on what you mean by chatter

 

Do you mean loose on the spline so that it is vibrating, or that the swivel (that you put your foot on) is loose on the shaft and is vibrating / chattering. This is normal wear and tear

 

If it's loose on the spline it can be because the bottom of the slot that pinches together has closed up so that when the bolt is tightened it doesn't clamp up properly. You can saw a piece out of the slot on the kickstart to cure that so that it clamps up tight again.

 

If the swivel joint is worn it can be re-bushed.

 

Or do you mean that the kickstart ratchet inside the gearbox is remaining partially engaged and chattering which you're stopping by pushing the kickstart return position fully home by applying pressure.

 

I think it is the kick start ratchet inside the gearbox.  I did tighten the kick start to the spline and it is tight. What is the fix for the ratchet?

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Not a problem I've come across so no obvious answer.  The kickstart ratchet is located on a spline and a spring sits behind it which pushes the gear along the shaft to engage with the kickstart gear when the kickstart shaft rotates. The ratchet has a shoulder around it's outside edge which runs at an angle. This shoulder locates behind a hook so that when the shaft rotates it allows the ratchet to slide towards the gear, pushed by the spring. When the kickstart is released and returns, this 'ramped' shoulder forces the ratchet to disengage with the kickstart gear and slide back down the shaft to its rest position.

 

The 'hook' has a threaded end and this is what you can see next to the kickstart shaft where it exits the crankcase as the the nut that holds the kickstart spring is screwed onto this thread (there are two nuts, outer nut is kickstart spring retainer, inner holds the 'hook' in place) On the inside of the gearbox, the hook has a flat edge on one side of its shank which locates against a flat edge on the inside of the crankcase. If it isn't seated properly it's possible it's not pulling the ratchet back away from the gear enough to completely disengage it. Ckeck the nut to see if it is tight but don't undo it as the tension of the spring inside may pull the hook through into the gearbox with the nut loosened off.

 

Alternatively, I've seen both the 'hook' mishapen which may also prevent the ratchet from returning fully, or the face of the 'ramped' shoulder could be damaged to the same effect. Only way to check that is an engine strip.

 

Check to see if the kickstart is fully returning against its stop, if the return spring is weak, or incorrectly fitted, it may not be returning it far enough to disengage fully.

 

Are you sure it's coming from inside the gearbox and it's not just the kickstart swivel vibrating because the top swivel joint is worn?  If it is the ratchet, the noise will rise and fall with engine revs. If you rotate the kickstart to engage slightly when the engine running you'll hear what the ratchet sounds like

Edited by woody
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If its the ratchet(which it sounds like it is ) , you will have to split the cases , I did one not so long back and it was the small peg which the ratchet rides up against was bent. Its a pain but its the only way to sort it . 

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Thanks for the help.  I will see what I can do this week.  

Finally found out how to send a video of the sound.  Highlight link then choose go to

I'm not sure how else to attach one here.

 

2 videos

 

https://www.dropbox.com/s/44yusw86v1yasbu/kickstart%20chatter1.MOV?dl=0

 

https://www.dropbox.com/s/y9gzf42dzqnvruc/kickstart%20chatter2.MOV?dl=0

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Sounds to me like the kick starter pawl is not clearing the ratchet properly. If moving the kickstart forward on the spline doesn't work, then the fix is probably inside the gearbox. Take a look at the exploded diagram attached, Parts 2,4 and 10. Item 4, the crank stop may be adjustable from inside the ignition cover but I don't know for sure as it is so long since I pulled one of these engines apart. Part 13, the ratchet stop or a broken return spring (part 3)  could also be the culprit.

Nov 14th.pdf

post-20659-0-93329200-1441768287_thumb.jpg

Edited by 1973tr6
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Hello yes as above am having some issus with my 199b rachet stop lucky for me the Engine is having a over all the stop Arm on mine as worn a groove on the end so it's not allowing it to keep the rachet in fare engouth away from the starter cog there for i will have this same problem as you if i don't fix it

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Larry i ham the rebuild man and i do have alot off exerience with bultacos but it's the first time iv'e took apart a 199b there basically the same apart from it having a 6 speed gear cluster. And 1 or 2 other things are slightly different. i do know the kick start return spring gets half a turn i half done it correctly the Arm has worn on the end i was inqiring if any body could let me if any other stop Arm would be ok for this model. have a grand day Larry.

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Thanks to Larry, I found out and fixed the chatter problem.  The end of the return spring was not around the bolt, so I used the trusted needle nose pliers and

a screwdriver and it went over with not much trouble.  I started it up and all sounds quiet.  As soon as the rain stops I'm going out riding again.  

Thanks to all of you for your information and help. 

 

Scott, (I expect all future fixes to be as easy, Moll)

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Incorrectly fitted return spring...?  did I mention that...?  :P  Glad it turned out to be the easiest of the potential fixes

 

Bondy - there is only one solution and that is to fit a new or a not worn stop. You may also need a new ratchet if the cam on yours is damaged as well. As soon as the hard edge has gone the two will just dig into each other and stick. 

 

Just measure it and ask In Motion if they have one,

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  • 8 years later...

Hi, 

Apologies for resurrecting a very old thread, but i have just rebuilt my Pursang engine and when starting the engine the kickstart ratchet was not disengaging, so constantly chattered. 

The thread above was very helpful and clarified what my issue was, as i missed the reference in the manual to rotating the kickstart shaft to set the shaft spring tension. Very time consuming error on my part!! 

I have stripped the engine down and again and have now tensioned the shaft spring.

Can i check if this is the correct position of the inner ratchet and the spring tension? I want to be sure before i put it all back together and back in the frame. 

Thanks very much in advance.

Max

IMG_0686.thumb.jpg.8c49d0d3e1c32631261ef3a74d17ec8b.jpg

IMG_0689.thumb.jpg.f7a8445fb91e89a2eae47ae27c213adc.jpg

 

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Max -

Ratchet appears to be correctly assembled, although I can't see ratchet spring. To ensure correct return spring tension, the kickstart shaft  also needs  to be in the correct position in rerlation to the ratchet. Viewed from the left side (outside the crankcase) the chamfered hole for the spring should face forward i.e. at 9 o'clock when the ratchet is fully disengaged against its stop.

woody's earlier response gives an excellent overview of what to look for.

While your engine is apart, now would be a good time to attend to the crack in the crankcase above the ratchet ......?

Edited by lorenzo
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