clutch slip

[oliverg]

On my '69 firebird I've recently put in new clutch springs, because when kickstarting the clutch slipped. However it still slips when kicking over, the old springs were 1-2mm shorter than the new ones. Clutch plates were in good order and thick enough. Filled with 10-40 oil.
Is this a common problem - when kicking on compression stroke? or maybe the clutch plates are soaked in oil?
Any advice appreciated.

[rhyatt]

I'm sure you've checked already, but clutch pushrod free play?

[DAVE BRADY]

Hi,

What type of 10/40 oil?  Additives in modern oils will cause slip.  Wet sump modern bikes use the engine oil through out but the clutch and oil are designed for this.
I have used ATF for many years and thousands of miles and it works well.
If after checking the clutch rod clearance, as suggested, try draining the 10/40 oil out and replace with ATF.  If you can get the bike running the 10/40 may then clear from the plates. Otherwise it may be necessary to strip the plates out for a clean.

Dave.