1970 CT70 shifting issues

B

boydsteve

New Member
Hey everybody,

This bikes runs pretty good but the shifting is difficult and at 25 mph or so if I let off the throttle coming to a stop the bikes downshifts itself. I read about loose bolts on the shift drum and I had the clutch cover off, the bolt holding the star (item 24 in diagram) was tight. Some said the bolt on the other end works loose so I pulled the other side cover and pulled the rubber ring and this bolt was missing (item 24). I put one in and tightened it down and issue remains. I read RePete's thread in which oil was discussed a lot - it's running full syn motorcycle oil (large quantity free from local shop that shutdown) so I'll make arrangements to switch that out.

Thanks in advance for the help.

Steve
 

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Bolt #24 should be installed with a dab of blue loc-tite on the threads and hand tightened to snug. The rubber plug helps insure that the bolt will not back out. If you tighten it right down, the movement of the shift drum makes it bind up, making shifting a major task.

As far as downshifting on its own, I'd have to say that the gear dogs are worn and have rounded edges, and, when you left off on the throttle, you're unloading the stress on the gears, and they will disengage.
 
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The shift drum stopper bolt is a special bolt. You would need to replace it with a genuine part. There is also no telling how much damage to the shift forks was done from riding without the bolt in there.
 
OLD CT said:
The shift drum stopper bolt is a special bolt. You would need to replace it with a genuine part. There is also no telling how much damage to the shift forks was done from riding without the bolt in there.
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That's important. It looks like a generic M6 bolt but it's not. The washer is special, too. Both parts are readily available new. At this stage, may as well replace them with the correct OER pieces and see what that does.

Jumping out of gear makes me think worn drive dogs, on one or more gears.
 
ok, will start with that since I need it anyway. when we say drive dogs, that's the gears themselves? or the teeth on the gears?

18, 19, and 21 on the partzilla drawing? some other searches show a bolt with a washer attached.
 
thanks guys, I've ordered the correct washers and bolts so we'll try that first and then check inside after we see if that makes a difference.
 
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