Clutch Slip.

[Glyn.G]

Hi everyone, Has anyone got any ideas as to why the clutch slips on my 77 GT380. It only happens when it's cold and after the initial slip on acceleration it goes away, then rides & handles fine for the rest of the day.
I have no problems with gear selection and can find neutral with ease at traffic lights. Could it be that it's just slinging excess oil off the plates. The oil I am using in the gear box ( engine oil ) is Silkolene Gear Oil Light, SAE 75 - 80 as suggested by my local bike shop.

[Alan H]

I use Duckhams 20w50 in my 550 without problen, maybe your oil is a bit on the thin side?
make sure it's mineral, not synth as it's too slippy for 70s clutches.
Also make sure the clutch is correctly adjusted at bar end, clutch end and release. If any are tight, it'll slip.

[Glyn.G]

Cheers Alan, I think everything is adjusted ok and all operates smoothly. I'll try some 20w-50w as you suggested.

[Alan H]

It may help to whip the plates out and give them a wipe too.
Make sure the springs are fully tightened so the plates have the best chance of gripping.

[Vintageman]

Suz recommnend 20/40 where in the heck do you find that these days

I use 15/40

Is your bike stock? I think oil type change is a good thing to try first as well if stock.

Its a rush/scary feeling when a plate slips and engine sundenly revs up ... even when it only happens cold

[Glyn.G]

Cheers for all the advice, I'll try an oil change first as I don't fancy pulling the clutch apart just yet. Maybe if it gets worse I may have to but as it only happens the once when cold under reasonably hard acceleration I'll leave it for now.
Regards,
Glyn.

[gt-keith]

I had a bit of clutch slip on my 380, especially when changing up in the higher rev range. Used Motul sae10w30 transoil, specially designed for two stroke gearboxes.
No further problems with clutch slip.