GT750M Clutch slipping when cold

[pennell]

Afternoon all.

I am having some trouble with my clutch slipping when the bike hasn't full warmed up, at the top of the tach from about 6k rpm-onwards. It seems to have been getting progressively worse over the last few weeks when it only did it in 4th gear. I am running a 20-40 motor oil in the gearbox, and I recently put that in when my gear indicator came loose and all my oil leaked out.

My clutch lever is almost all the way out before it grabs, and my barrel adjuster is also all the way out. The bike has 15xxx miles. New clutch possibly or just an adjustment?

Any input would be greatly appreciated.

[Craig380]

It does sound like the friction plates have given up .... it's probably worth a final check that the cable runs free and isn't sticking, and to check the adjustment at the pushrod end of the clutch.

If that all checks out and it's still slipping, then it's clutch rebuild time. I'd strongly recommend fitting new springs at the same time, while you're in there.

A few years back I did the clutch on my 380 with EBC aftermarket friction plates and springs. Pretty cheap (around 50 USD total for the parts). The metal plates are usually fine, and should just need a clean up in carb cleaner or similar.

Two quick recommendations -- soak the new plates in clean gearbox oil overnight before you fit them, and be very careful with the clutch spring bolts when you refit & tighten them .... the threads can strip really easily. Just nip them up using a short socket handle.

[oldjapanesebikes]

Just to add to Craig380's comments - I was surprised at how much 'set' the old clutch springs had taken when I re-did my 1975 clutch. The plates themselves actually were not bad at all although I did change them also - I think the problem was mainly the springs. In the photo (where the problem was mainly the focus ) - old on right, and new on left.

[pennell]

Thanks for the help folks. I should have added as well that when shifting up, it pops out of gear sometimes as well; almost like you can hear the gear spinning and clunking around in the transmission until you let the rpm's down and then a firmer lift of the shifter will make it go.

[Craig380]

The popping out of gear might be related, or separate ... I'd do the clutch first, give it fresh gear oil and see how it goes. The clutch centre nut could be loose, too, happened on mine ...

[Coyote]

The clutch centre nut could be loose, too, happened on mine ...

+1 If it's noisy, the clutch nut is probably loose. Easy fix. Clutch friction plates should last longer than 15,000 miles. My GS1000 has 26,500 on it's original clutch and still working fine.

[Wayne Meuir]

You might want to try using gear oil in the tranny instead of motor oil and see if that helps. I think GL5 is what is recommended. I use Gear Saver in either 80 or 85 weight and have never had a problem with slippage. Lots of guy use Wally World gear oil, which is half the price of Gear Saver.

Wayne