Clutch slip under power after 140 bhp

[Foz]

     My bandit 12 has now got its tuned engine fitted and after a break in period it's been back on the dyno, initially the clutch slipped so the plates were all changed however I was led to believe it had one heavy duty and one standard diaphragm Spring fitted , I since think both springs were standard.  After the new plates were fitted we tried another run and again it started to slip but only slightly this time as the engine started to come on cam at about 8-9k this was about 143 bhp according to the print out. 
 I think I remember FB saying he used just one hd Spring on his 150bhp bandit without issue, I know I can go down the gsxr Spring clutch route but initially was going to definetly fit one hd Spring possibly even two . Opinions by those in the know would be useful, is two to heavy ? Any other suggestions  

Edited April 30, 2016 by Foz
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[fatblokeonbandit]

Fozzy, mines 150 like you said, i fitted all new  genuine fibers and  onr hd barnett spring and it's been spot on ever since i fitted it in 2009, and mine is just used on track days and hill climbs...check the steeles 2 are thicker or should be, mine came from new with all the same size.

[Foz]

Annoying part was is that I had a Barnett HD Spring at home but not at my mates dyno so now I've got to take it back for a final set up as we couldn't get a full power run without the clutch letting go.  Would two HD springs be overly heavy ?

Edited April 30, 2016 by Foz

[fatblokeonbandit]

I did try with 2 in another bandit i had, it was fekin heavy,  but not  so heavy for track use,  traffic might be a diffefant story

[Foz]

I can live with heavy, I have a TL remember :-) as the bandit really starts to pull at 8+ that's when it lets go .One maybe enough for day to day use as the likelihood of using it on the road near the red line isn't likely to often. But still be nice to get a full power run in to check the fuelling and see what it's got in it

[Oilyspanner]

I must've missed the post, what mods have you done to your engine Foz ?  - sounds pretty good though (apart from the clutch !).

[Rene EFE]

Friend of mine runs a very big turboengine using 3 stock springs. It's well over 300Bhp so if yours is letting go at not even half that, I'm suspecting warped plates. 

[Foz]

Rene, to be fair the history of the clutch was a bit Unknown .It could well be the original 43,000 mile clutch plates and springs, all the steels were in good condition and it now has new friction plates the only thing I didn't have with me were some HD diaphragm springs so initially we'll go down the route of replacing them. 

Oilyspanner, the engines now got a wiseco 1216 block and Pistons, gsxr 11k cams, a heavily ported and flowed head with 2mm oversize inlet and exhaust valves with heavy duty springs , rs38 flatslides , full 4-2-1 akrapovic exhaust system with a yoshimura rs3 end can , it should have all the ingredients for some good power. 

[fatblokeonbandit]

First foz, check the stelles, no 5 and 6 should be 2 mm all the rest are 1.6 mm so if, like mine, it came from the factory with all 1.6 mm steels, you have no chance.. mine worked fine until the first time I went on a track it lasted 5 laps then slipped like buggery, too a while to find out what it was..

 

ive got one barnett spring if you need it shipmate..

[Foz]

I'd got one in the garage along with a set of ebc ones and a set of Barnets is on way so between them I should get it sorted.The steels were totally unmarked but will check for the two 2mm ones when the springs go in

[dougw]

Two heavy duty springs was fine for me till in heavy traffic getting out of Donington once.

Then it wasn`t.

[SFC]

just a thought but maybe previous owner used fully synthetic once ? an old mate done the same many years ago and he only went 10 miles with it in , dropped oil , flushed out and filled up with correct oil , the clutch kept slipping in high revs for 8 months before he ended up buying new plates

 

[Foz]

I've had this bike for 4-5 years Carl and always used semi synthetic ,the clutch could be the original for all I know so it's probably best being changed anyway considering the power increase

[VJ]

I ran 2 HD springs before, it was a heavy clutch but not unrideable

[Screwriverracing]

You can always take the steels out and have them shot blasted, rough them up a bit and gives more grip, done this on  a few GSX's and works a treat.

Cheers SRR