80 CB750F clutch problem

[dicken]

hi. newbe here. i'm rebuilding my 80 cb750f and it runs but is really noisy at idle. i took the clutch apart and noticed that the gear that is riveted to the basket is loose. it rocks back and forth about an eigth of an inch. i have two baskets and they are the same. is this normal? can this be fixed? i checked and the cush drive in the primary shaft is good. my spare primary shaft is not good. i have gone over all the timings and everything is good. thanks for your consideration. ken.
i have since installed a stock air box, stock exhaust and chrome front fender.

 

[amc49]

Depends on how loose, there is always SOME movement there, it's another cush drive. Honda was et up with cush drive on those, why one of the clutch plates is a double riveted plateset too. 3 cush mechanisms there.

Good one should give but not easy.

If idle is rattling things the riveted clutch plate can do it if the rivets are loose. The primary will make noise too if the carbs are not synced well or there is one cylinder putting out less output than the others. Idle speed set too low will do it too.

All that cushioning is why the clutch is not good for spit if say drag racing, it's WAY too hard to modulate to slip just enough for a max rpm launch. It either slips too much or suddenly quits and locks too much to lug the motor down.

 

[dicken]

Depends on how loose, there is always SOME movement there, it's another cush drive. Honda was et up with cush drive on those, why one of the clutch plates is a double riveted plateset too. 3 cush mechanisms there.

Good one should give but not easy.

If idle is rattling things the riveted clutch plate can do it if the rivets are loose. The primary will make noise too if the carbs are not synced well or there is one cylinder putting out less output than the others. Idle speed set too low will do it too.

All that cushioning is why the clutch is not good for spit if say drag racing, it's WAY too hard to modulate to slip just enough for a max rpm launch. It either slips too much or suddenly quits and locks too much to lug the motor down.

thanks for the response. i got a rebuild kit for the basket cush coming. i will check out the double plate rivets. after looking real close and seeing enough wear i've decided to do everything. cam chains, primary chain, primary cush. the carbs have been synced to perfection with two different setups, guages and mercury. it was hard to get the dots on the cam sprockets in the right place at the same time, probably because of old chain. it would change when tensioners were let go. it's a shame that one has to tear it all apart to change the cam chain so might as well fix everything and it will out last me. ken.

 

[amc49]

Don't tear down without changing the valve seals..................Viton only. Most any seal other than those even the best Honda OEM and other maker names like APE are now selling crap seals, the gasket kits do the same. A super bad problem. The seals cook to leak in a couple months and then motor starts burning oil.

The riveted clutch shock plate can be replaced by two normal steels placed back to back and then no motor rivets coming loose to fall in motor and tear things up.

If the valves have never been quality set to .005" then much of your sync issue can be there. The engine will not balance individual cylinders that are off from valve leakage past a small amount. Compression numbers would show that.

 

[amc49]

Oh, bump the oil pump pressure bypass with like a 1/16" thick washer, the slight bump in pressure will quieten a bit more of the noise. The rattle at idle commonly from primary chain tensioner loosening when the idle oil pressure drops off.

 

[dicken]

thanks for all the input. i will check out all this. the head is all rebuilt with new seals and the clearances were all set. i thought i did enough but i didn't so now i'm doing it right this time. any more tricks up your sleeve? thanks again, ken.