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Freeing the clutch question...


yellow_cad
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I have a 1974 Ossa MAR. If it sits for any period then the kick start lever will not kick freely to clear the clutch.  I let it sit for days with the clutch lever clamped to disengage the clamp.  It still doesn't kick free so I read on this board some time back that one way of dealing with this problem is to put the front wheel up against the wall and then start the bike.  I did this and even though the clutch was not free, when I started the bike it ran as if the clutch was disengaged.  What am I missing here?  I need to take it somewhere to ride it and do any shifting so I haven't (I'm 73 yrs old so lots of trial and error is hard work). With it up against the wall with it running should I then try to put it in gear and if so, what gear should I try first?  Thanks for any help on this.  Jim

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Jim, pop it into 3rd or 4th gear - pull in the clutch lever and rock it backward and forward - the clutch should release then you can start it. I'm sure an Ossa specialist will be along soon but try this. It does sound like your plates are sticking - have you tried the obvious - correct oils and correct quantities - correct free play at the clutch lever ? Hope this helps. Cheers Paul Mac

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1 hour ago, paulmac said:

Jim, pop it into 3rd or 4th gear - pull in the clutch lever and rock it backward and forward - the clutch should release then you can start it. I'm sure an Ossa specialist will be along soon but try this. It does sound like your plates are sticking - have you tried the obvious - correct oils and correct quantities - correct free play at the clutch lever ? Hope this helps. Cheers Paul Mac

Thanks, I do use ATF, and sufficient free play, but not sure what you are referring to regarding level.  So, you're saying to pop it in 3rd or 4th after it is running with the clutch lever disengaged and leave the clutch lever disengaged or not?

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By level I mean the correct quantity.

Do the above procedure before you start it.

Bike on the ground with you on board and engine off.

Pop it into 3rd or 4th gear - pull in the clutch lever and push the bike backward and forward with your feet - the clutch should release then you can start it.

 

Cheers

 

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Hi Jim, I've not worked on an old Ossa clutch, but there may be a couple of things to look out for. One is the condition of the clutch centre and clutch basket, where the clutch plate "ears" or "tabs" connect, on older bikes, the long term use of the clutch can cause the tabs to cut grooves into the basket, I have seen this on Bultaco's that I have worked on, which may prevent the plates freeing up. The other more usual problem, is that the plates are sticking together hydraulically, one way to cure this is to drill 5 or 6 holes in the annulus where the fibres drive the steel plates, 6mm dia hole is sufficient. It worked for me on a 301 Fantic that used to go forward still when you pulled the clutch in. Maybe if you have all steel plates, this is not the answer!! I never liked the idea of forcing the disengagement with the front wheel up against a wall. Bye, Peter B.

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I agree with B40T.  start bike, make sure you have some open space in front, give the bike a little roll forward with your foot and ride 10 or 20 feet with clutch in until it clears.  A little blip of the throttle should do the trick.  Some modern bike clutches stick too.

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Rock the bike and get it into neutral. Make sure it is neutral and not a false position. Start the bike and get it thoroughly warmed up. Make sure you have approx 2-3mm free play at the clutch lever ( on handle bars). While you are warming up the engine operate the clutch lever a few times. Now kill the engine, select second gear and try to move the bike with the clutch lever pulled in. If its still stuck then the first course of action is to dump the clutch oil and fill with the correct quantity of ATF. Now each time before you start the bike do as previously suggested, select second or third and pull the clutch in and rock the bike back and forth....this normally works. Even if you stripped the clutch and deburred the clutch basket and thoroughly checked the plates you might still have a stuck clutch after a few days standing idle. Bultacos suffer the same issue....not all but quite a few. Making sure the clutch operating mechanism is well serviced and set up is a good idea in any case, especially ensuring the best cable run and cable freedom. Hope you adjust to the issue??

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46 minutes ago, section swept said:

Rock the bike and get it into neutral. Make sure it is neutral and not a false position. Start the bike and get it thoroughly warmed up. Make sure you have approx 2-3mm free play at the clutch lever ( on handle bars). While you are warming up the engine operate the clutch lever a few times. Now kill the engine, select second gear and try to move the bike with the clutch lever pulled in. If its still stuck then the first course of action is to dump the clutch oil and fill with the correct quantity of ATF. Now each time before you start the bike do as previously suggested, select second or third and pull the clutch in and rock the bike back and forth....this normally works. Even if you stripped the clutch and deburred the clutch basket and thoroughly checked the plates you might still have a stuck clutch after a few days standing idle. Bultacos suffer the same issue....not all but quite a few. Making sure the clutch operating mechanism is well serviced and set up is a good idea in any case, especially ensuring the best cable run and cable freedom. Hope you adjust to the issue??

Potato patato.

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19 hours ago, yellow_cad said:

 With it up against the wall with it running should I then try to put it in gear and if so, what gear should I try first?  Thanks for any help on this.  Jim

Putting it against a wall and slamming it into gear, which is what you'd have to do, is not a good idea. It's the same as having a working clutch and putting it against a wall and slamming it into gear without using the clutch. You could damage the gearbox. If it didn't mash the gears all it will do is spin the wheel.

Putting it into gear and rocking it, or riding it round with the clutch engaged until it frees will only work if it is not stuck fast. I've had a TYZ Yamaha with a sticking clutch with the same behaviour as yours and sometimes it could take 10 - 15 minutes of riding by snapping the throttle and bouncing the suspension to free it off. Then one day it wouldn't free off at all and the only cure was to strip it, clean off all the plates and reassemble and it hasn't done it since (ie; cleaning the grooves between each fibre pad and cleaning the pads with brake cleaner and wire brush to remove impregnated oil)

As yours is a recurring problem, each time you leave it, if it was mine I'd pull the plates out, it's not a long job. I'd then clean off the steels and replace the friction plates with Barnett friction plates (or even fit a full set of friction and steels) Then make sure it was adjusted correctly and reassemble. I wouldn't use ATF as it isn't what Ossa recommended, I've no idea how effective that is in an old gearbox with bronze bushes.

I use Barnett friction plates with standard steels in both of my MARs and because the friction material is better it allows the spring tension to backed off more than normal which gives the benefit  of a lighter clutch pull. The clutch also disengages cleaner and very rarely sticks even after standing unused for months

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