clutch plates warped?

O

OB_daddy long stroke

Registered
got my clutch apart...fibers all look good... metals definatly got heated up (most of the outside plates are completely discolored), back ones less discoloration, but still show burn, or, blue, spots in about 3 locations..when i lay them flat on a glass table and put my finger on on side, the other side BARELY comes up on opposite side, and i mean barely, probably 3 thousants, or just barely enough to see a tiny bit of light through. when i put very light pressure (weight of my hand) on side that is up in the air, it flattens out no problem...is very slight warpage o.k.? or can they be sanded and put back in?
thanks-
 
do not sand! .004in is the service limit. replace if more than that use oem they are the best
 
Glass is not necessarly flat. We use a precision flat granite surface plate. Most aerospace type machine shops have them. Take your clutch plates to one and check them.

Jay
 
You will have to use a surface plate.[ours is granite also] If you figure they're flat,bead blast them with a fine glass or plastic bead. I usually get one clean up using a fine glass bead, next time replace both fiber and steel plates. I recomend oem for fiber and steel,they are the best all around. [drag racing clutch kits work great for drag racing but leave a little to be desired for everday drivability.] Just blast the shine and the discoloration off the steel plates and you'll be good to go with some new fibers.[I use stock springs also] Good luck.
 
thanks guys..next question- if i take them to a precision machine shop, and they say a couple are flat, acouple are .004 warped, and a couple are, say, .010 warped, do i replace all, or just some, or are they still within "real world" limits. what are your standards? i had a clutch "chattering" (bike is used a lot for drag racing) problem, and just put in new large outer basket, schnitz springs and motorheads support hoping to get rid of chatter,,,could plates be causing problem?
 
I have never replaced part of the set. Always the whole set. You may be able to use some good used ones and the rest new though,J.C. should have good advice on that. I never leave anything to chance on the bikes,my wife and I ride awful hard sometimes, but another reason is I dont want to have to do the work twice. Like I said, I usually change the steels every other set of fibers, using the blasting method. Be careful not to blast away too much material. Just enough to remove the coloring and glazing.

Later.
 
I've never actually measured my stack height, I usually just replace them and call it a day...As for the 4 thick fibers I think it works great and I'll continue to use them. I was even thinking of trying 5 next time but that might be a little to mutch. If any of your steels are warped at all replace them all! If there not warped and look pretty good I just hit them with a glass beeder and clean them up and re-install them. As for the thick fibers I have them on the inside. I'm not sure if the placement matters at all really?
 
yes JC, the new basket springs rattled (every spring, except one small one)..now im confused..maybe old basket could have been damaged in other ways? i did not replace inner basket-slight notching where plates touch it, but nothing bad....but, then again, i haven't tried out this new basket/springs combo at the track yet. hopefully tomorrow. by the way, when i had spacers welded into the springs of the original basket to tighten them up, the chatter went away, but i couldn't launch bike above 3000 rpm...even with clutch all the way in, bike would hit approx. 3000 rpm and start to creep forward on the line! so i figured i had better try out a new basket anyway...a couple of my friends have brock mods and can launch @6000 no problem, no chatter...chasing a ghost....
 
Warped plates most likely cause of "creep" at the line. Some aftermarket plates, with soft fiber compounds can also cause this. OEM Busa has 2 thick, and 8 thin fiber plates. I use all thick plates. Clutch stack can be spaced to use 8 or 9 thick fibers. I'm also using thicker steel plates, so I have 8 fiber, stock springs, shimmed about 2 mm. each, with brock shims, and device. ....... ...Fiber plates from '83 to '85 Kaw GPZ 750, are same dimensions as "thick" Busa fiber plates. GPZ steel plates are .015" thicker. ....The first time I fried OEM plates, in early '99, I used a set of GPZ plates hat I got for $ 20 total, at junk yard. Nothing else available at the time, being early in a first year bike. They actually worked better than OEM Busa. I have since got Barnett fibers, ordered as GPZ plates and put them in Busa. 4 months of drag racing only wore .030" from total stack height. I had just taken them apart for inspection, and measuremet. Clutch was still working fine. I just re-shimmed stack height to orignal thickness. This can be done with various combinations of OEM vs thicker steel plates, or even doubling up a pair of steels.
 
It's been awhile since I've been into my clutch. ( too damned reliable :) ) I believe stack height to be 2.00". A quick visual reference: You can unscrew oil filler cap and see last fiber plate, that sits i it's own notch. You may have to put in gear, and rock bike a bit to line up the correct clutch tab, to see it. The fiber tab should sit half way in the notch. It will be near bottom of notch, if clutch is worn. When stack height is too low, pressure plate will bottom out on inner hub, also. If that happens, all the springs in the world won't help.
 
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