Katana Owners Club U.K.

On the race bike the clutch has been slipping, it does it when cold, well the engine seems hot but it in morning practice, warm up lap, maybe first couple of laps, seems like the oil temperature has to be right up then it doesn't slip. It didn't do it last year and I'm using the same make/type oil, when the engine had problems last year the clutch did potentially get contaminated with all the crap that was in there, I cleaned the fibre plates with old tooth brush and lots of brake cleaner then soaked them overnight in fresh oil before fitting, they were clean, First time out last year it did slipped and I put 3 heavy duty springs in, I'm wandering if these weren't that good and have gone soft ?

Looking for opinions, the plates have plenty of meat and when it's not slipping it's all good and the bike gets off the line so well I make up loads of places if I'm down the grid so want to keep it the same. I'm thinking try a new set of springs, maybe EBC ones which are supposed to be 10% stronger (20% would be better thought), I have somewhere some really heavy ones but I need to be able to work the clutch.

Cheers

The plates are standard Suzuki ones, I have a new set of EBC fibre plates but don't really want to use them, tried different makes years ago and the standard ones were by far the best.

Try putting a thin washer under each of the springs to give more tension........

Tried that Friday night at the track Rob, had to re adjust the clutch after so I know it did something but the clutch slip was still there. I find it odd that once the bike has been out and used hard the slip goes away.

bobster wrote:Try putting a thin washer under each of the springs to give more tension........

If we are talking GSX 1100 clutch this would be pointless. For more preload you have to shorten the spacers living in the springs, I'd go for a millimeter, not more at a first try.

stock plates are great, but for bite and feel, ive never had a clutch that feelt as good as a set of barnett kevlar plates. they just will not slip.

qnd they tool a half a second off my quarter mile time.

Pedda wrote:

bobster wrote:Try putting a thin washer under each of the springs to give more tension........

If we are talking GSX 1100 clutch this would be pointless. For more preload you have to shorten the spacers living in the springs, I'd go for a millimeter, not more at a first try.

This is what I thought was done to my big popup years ago but couldn't remember. think i'll get some new ones made up as the ones in there are badly grooved from the springs, what's the best material to use and do you know the standard length incase the ones in there have been altered.

johnr wrote:stock plates are great, but for bite and feel, ive never had a clutch that feelt as good as a set of barnett kevlar plates. they just will not slip.

Unfortunately got to stick with what I've got, no budget for new ones, so it's std which measure up good or EBC which I'm trying to avoid using. I'm going to try Pedda's suggestion and shorten the spacers first.

For friction plates you also might have a look into this:
http://ballisticperformanceparts.com/" onclick="window.open(this.href);return false;

They sell a set which is also used in the Kats that Steve Martin and Shaun Giles use in their Kats racing in Australia's classic racing series. Iirc more than 170 hp in those engines. Also: cheaper than OEM. Got a set recently from there, good and fast service. Planning to put them into my coming race engine.

Will dig around if I have a measure of those spacers somewhere. About 12mm if memory doesn't fail me, but will try and check. I recon that any cheap aluminium chunk will do nicely, no high alloy stuff, as it's better to have the spacers wear out than the springs, I think.