XR70 Clutch Won't Disengage When Shifting

[zrxer]

Hey guys. I'm working on a neighbors XR70. The complaint was "It won't go". First off, I had to clean the carb as gas had sat in it for some time. Got it running and there was no shifter action. The shifter would move freely up and down but no gears were moving. Removed the clutch cover and discovered the spring loaded shift drum wheel/arm dealy was broken. Replaced that, now it shifts through the gears but the clutch won't disengage when shifted. Adjusting the clutch screw in the case does nothing.

I have removed the clutch and disassembled it but can find nothing wrong. Reassembled everything and still the same outcome. I'm at a loss here. Everything appears to be in place and moving as it should when engaged but still acts as though the clutch is stuck solid.

Any ideas, input or comments are greatly appreciated. 

Thanks.

[dirtbkr188]

Sometimes, the small primary drive gear that fits into the back of the clutch assembly does not seat all the way in place when installing the clutch back onto the crankshaft. As a result, when you install the clutch cover, the adjuster inside the cover is pressed up against the clutch and will not work properly. I usually install the primary drive gear into the back of the clutch before sliding it onto the crank and aligning it with the big primary drive gear. Also, tighten the clutch nut with a ratchet and extension, if you overtighten the nut with an impact gun, the clutch will not work right either.

Edited April 3, 2017 by dirtbkr188

[zrxer]

Thanks for the response dirtbkr188. I installed the primary gear before installing the clutch to the crank--as you have--to make sure it seats properly.

Your second point of tightening with an air gun is what I did the first reassembly. I'm sure I over tightened the nut and distorted the bushing. I pulled it apart again this morning and found the bushing had affixed itself to the primary gear. Used a punch to drive the bushing out and sure enough, it is squished--larger in diameter in the middle where it had expanded when being smashed together by my air gun. D'oh! The second time I pulled it apart (I missed the bushing being stuck) I torqued it to the proper spec but it was too late--the damage was done.

Will order a new bushing and report back with the results.

Thanks for your help.

[zrxer]

Installed the new bushing and the clutch works perfect now.

Don't overtighten the retaining nut when reassembling!  Bad things happen. ?