Clutch help PLEASE

[RapKor]

OK here it is, we have 1 more race left, took a 2nd and a 2nd today for a second overall, not bad but should have could have won if my rider wasn't 12 bike lengths behind the leaders going into the first turn. After the bike gets going it is a rocket! He was able to make his way to the leader in each moto and both motos he just ran out of time.
Bike runs real strong it's a Kool Kids built 08 DRR 90 l/c ported and polished,stock 08 gearing, Keihn 24 mm carb 120 main and 42 pilot,we are running the stock clutch (YAMASIDA)with a 1500 ztr torque spring (brand new every race), red malossi clutch springs and 4.0 and 4.5 gram rollers staggered(also new) with the 787 belt ( 3 races on it).
Heres the problem, bike is dead *** slow for the first 20 feet then it's a rocket but unfortunatley that first 20 feet is terminal! It is almost like the clutch slips or doesn't grab when it first engages. We have 1 mini race left in our careers as we are moving up to the 200 class next year, would love to win our last race. Need some help getting this thing dialed in I will say that the clutch shoes looked quite worn and I did not notice this until I tore it down Friday nite to do the final race prep, I usually scruff the variator with a scotch brite and I hit the shoes with some sand paper to scruff em a little. Could this be my issue? I am definatley going to change the clutch but not sure what too get, do not want to spend too much as it is our last race. Any suggestions on what else it could be? I would really appreciate any help Thanks!

[selbygirl]

did you try lighter roller wgts a few years back wen my boy was on a 50 i had 3.0 gram during a race i took a 1/8 drill bit and put several holes in the rollers made the rollers 2.8 gram and sanded the drilled hole edges to make smooth good luck tommy

[greenmachine70]

pm'd

[cik orange]

sounds like your bike is shifting to fast. but need a little more info is it reving up fine just not engaging or bogging down and gradualy building speed?

[RapKor]

It is reving fine seems to just take a second too engage almost like the clutch is slipping????. The motor pulls real strong and revs great, best plug read I have ever had with this motor, sounded great coming through the sweeper corners. My rider stated that the machine did not bog just seemed to hesitate for a second when the gate dropped. Thanks i appreciate the help!!

[cik orange]

ok if it is reveing out fine buy dr pulley hit clutch or malossi delta and a new belt. if this is not in your budget get a new yamasida rear and belt (just 10 thou wear of a belt is huge) and go up 1 or 2 teeth in the rear if your kid is cathing them at the end of a run your not getting there fast enough (gearing to high). i sent you a pm

[selbygirl]

is like a dead spot at start off in the motor we had 70 motor do that it was dogging at the start but ran good if you pin it. it was low compresion in the motor some peaple say bad crank seals do it also it only takes a second to chek your comresion did you check your roller wghts you sed you had 4 gram wghts just put 5 of them in see if it helps if it does get some lighter ones good luck tommy

[RapKor]

Compression is good, fairly new top end 1 race on it ( well 2 now) but I did check and it was same as when I finished re build. Almost seems like the bike almost has to over rev before the bike takes off. Really hard to explain but it is like it revs and grabs but really gets a hit and grabs 20 feet into the run almost like a delayed reaction. Somone suggested that there is a pressed together shaft in the transmission that the sprocket mounts too that maybe slipping?? Does this sound possible? Have never been in the tranny on this bike or any other 90 for that matter. What ya think? Going to try a new clutch soon but I am hesitant to run something different then the Yamasida as I know that one pretty well. Like I said in earlier post this is a new issue. Thanks again.

[qcitytile]

I would bet the rollers are a little heavy. Had the same issue with a motor last year. Flat on the lunge then would go like crazy. Maybe check slipper sprocket if you have one.

[greenmachine70]

Dr Pulley