help? zx9 clutch slip

[jd2316]

I got a 99 zx9r with 26,000 miles a few months ago, noticed the clutch slipping under hard acceleration and put in a new clutch, kevlar frictions, steel plates. didnt do new springs as the oem ones are within tolerances. Put it all back together just fine, But hell, the clutch is still slipping, only under HARD acceleration (is there any other kind?!) What the hell?! any suggestions would be welcome, need my daily driver running right asap! Thanks

[mick12]

what oil is in it do you know maybe the original owner used an oil with friction adds just a sugestion if you havnt changed the oil it could be worth a try

[jd2316]

Ive been running castrol 4t motorcycle specific 10w-40 conventional. when i put in the clutch, I gave the bike its second oil change under my ownership. I've been going thru the bike and replacing/ doing maintenance as the po was not mechanically inclined at all and had been sloppy about the upkeep of the bike. going to try new springs next. as i understand, this bike has a hydraualic clutch that operates off the brake fluid, maybe flush that too. It just started this clutch slip shit about a week ago

[Gosling1]

new springs should sort it out - go with EBC springs, 15% stronger than stock.

[MadKaw]

new springs should sort it out - go with EBC springs, 15% stronger than stock.

^^ this

My old 9 would slip under power in 3rd. All bits were in tolerance so I put in some barnett springs and all was well.
Most of the aftermarket brands are 10 to 15% stronger and only about $40 a set..

[jd2316]

I ordered some barnett springs yesterday, and will install them tues when they arrive. The clutch kit I bought on ebay (from outlaw racing) came with a set of springs but since they were about 17mm shorter than the oem ones that were in the bike, I just put the oem springs back in since they were well within tolerances. The guy at the speed shop I ordered the barnetts from said it was most likely some chinese shit that i got off ebay, which would explain the spring length difference. So I was messin with the bike today, getting it ready for summer riding in arizona- coolant flush, wrapped the header/midpipe etc, And figgered what the hell. Put the springs that came with my clutch kit in,mostly out of curiousity, and I can say the clutch slip is not any worse than it was with the stock springs, lol. it let go on me only once, 3rd gear at about 8000rpms, and re-engaged (smoothly) when the rpms came back down to 5 or 6. Hopefully the barnetts will clear this shit up on tues. Thanks fellas, appreciate the insight.

[paulsj]

Can also try putting a washer under the springs to add some extra tension for the 9 spark plug washers work a treat.

[jd2316]

Got my new barnetts yesterday, installed them this eve, and all is well. Never buying internal bike components off ebay again! Thanks fellas for the advice!