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Dragging clutch & shift issues - 1972 CB

Mogo

CB750 Member
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Hi all, I found a few posts in here about clutch drag & I've been scratching my head over a problem with a recently completed build on a 72 US delivered CB. I bought it years back, started it but never rode it before putting in the shed. It's been a slow project but since finishing I haven't been able to get the clutch to operate properly. It won't go into gear without stalling when cold, and if get going by clicking into gear while rolling (engine running) the clutch disengages between gear changes, but not without a totally unacceptable delay, and then when you pull up you need to hold the brake on, and it's impossible to get neutral. I found elsewhere in another forum suggestions of age related problems with o-rings in the oil pump & counter-shaft oiler casting, as well a need to drill extra holes in the clutch centre, all of which I've done to no avail. The adjustment method & process I know about, and the cable is new. I have the bike on a rear wheel stand, removed the springs and plate lifter to confirm that with no pressure on the clutch pack it will separate and spin as you'd expect, but even with only 2 springs in place, once I tighten the lifter plate bolts by hand it locks the clutch plates & the rear wheel will not spin without turning the motor over.

If you look at the pics the centre and basket does not appear to have wear sufficient enough to cause the plates to not release?

Any advice will be greatly appreciated, and I have stacks of pics for any question.
20231113_180106.jpg
20231113_175258.jpg
 
I would start looking at clutch plate stack up and possibly they are aftermarket, aftermarket disk kits are sold as the same kit for all the sohc years but they changed the clutch couple times through the years. Other wise its kind of hard to diagnose without it being able to see it and feel it personally. Maybe with some more pictures we might be able to catch something:shrug:
 
Anyone?
I would start looking at clutch plate stack up and possibly they are aftermarket, aftermarket disk kits are sold as the same kit for all the sohc years but they changed the clutch couple times through the years. Other wise its kind of hard to diagnose without it being able to see it and feel it personally. Maybe with some more pictures we might be able to catch something:shrug:
Thanks DD, I have any number of pics. I checked the plate thickness & they're well within spec but I have no idea as to manufacturer. I've ordered a Newfren kit today simply to see if this makes any difference, but I'm not hopeful. Here's a few pics, anything else just ask, & thank you for trying to help.
 

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Hi guys, the mystery has been resolved for those interested. Thanks to the the legendary Hondman, the problem identified was the type of clutch plate fitted by the PO. Replacement with the traditional multi-slotted cork type, properly prepared before install, and with the correct run-in process, has provided a perfectly working clutch.

Thanks to all who contributed.
 
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