The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Borderer on 04.09. 2013 10:38

Title: Strange clutch slippage problem
Post by: Borderer on 04.09. 2013 10:38
This is a wierd one!
BSA Super rocket with Triumph 4 spring clutch not a new installation
New plates, friction and metal, new springs, pushrods straight and cut with ball bearing in middle, basket and center deburred. Everything working as it should BUT
The clutch slips quite badly for first 10 miles or thereabouts, after that it is perfect!!
I fitted a new cable, there is free play at the gearbox adjuster when cold. I did the ball bearing mod on the advice of an old classic trials rider, as it allows the rod to centralize and not catch on the tube.
All I can think of is once a certain temperature is reached something is freed off but what?
It's livable with but a bit annoying, I suppose it stops over revving a cold engine though!
Title: Re: Strange clutch slippage problem
Post by: bsa-bill on 04.09. 2013 12:20
New plates with nice sharp tangs on them, could they be snagging in the clutch drum slots when cold and then fine once it warms up a bit - a random thought
Title: Re: Strange clutch slippage problem
Post by: morris on 04.09. 2013 13:15
How have you filled the basket up?
Started with a plain plate and ended with the same or did you put in a friction first?
Title: Re: Strange clutch slippage problem
Post by: Borderer on 04.09. 2013 19:30
Plates plain to plain drum slots smooth as a politicians excuse,
Title: Re: Strange clutch slippage problem
Post by: chaterlea25 on 04.09. 2013 20:00
Hi Borderer
What lube do you have in the primary??
A lot of oils make the clutch slip  *sad2* *sad2* (car ones)
Which springs did you fit?? I can recommend the Triumph type supplied by SRM
A lot of springs out there are to heavy and too short  *ex* *ex* *ex*

HTH
John
Title: Re: Strange clutch slippage problem
Post by: RichardL on 04.09. 2013 23:02
I know that my clutch slips a little more when cold by the way I can shift into first clunk-free when cold at a stop, but with a bit of clunk when hot. This said, I don't have to go 10 miles with slippage. I'm thinking that cold ATF (in my case) is more slippery than hot ATF, or, that hot plates and friction material have expanded, or a bit of both. How about just giving the nuts another turn, or so, to just barely disengage when cold? I'm just guessin' so feel free to wait for some better answer if you don't like this one.

Richard L.
Title: Re: Strange clutch slippage problem
Post by: anjimehra on 15.01. 2014 16:53
Try transmission oil in the primary casing
Anji
Title: Re: Strange clutch slippage problem
Post by: Topdad on 15.01. 2014 17:06
Metal plate slightly warped ,when cold more resistant as it warms more malleable and flattens or the oil, mine slips slightly until warm but just have a careful wrist until its happy ie when its warm, cheers Bob.