Clutch Problems

Clutch Problems

Q. I have a 94 zx7r and my clutch started to slip the other day after learning how to leave the line drag racing. it only slips between gears right now but I know its only a matter of time. what is a good clutch and can I install it myself? Also after a 160 mile ride at a average speed of 90mgh my bike sounds real buzzy like something is loose I checked and could’nt find anything loose any ideas? the bike has 16,500 and I just had the valves adj and carb sync. Runs great feels a little slow but that’s because I weight 225 and 6’1″ any help would be great thanks.

A. I would buy new factory steel plates as I earlier described and factory friction plates. True, the friction plates are what wears out but if you install new ones without checking to see if the old steel plates are warped, you will still have problems. I checked the Barnett springs on my Rimac machine and they measure about 36 percent stronger than stock, that’s why I recommend only using 3 of them with 3 stock springs. On this setup I have made over 200 passes with no problems on my ZX7R running Nitrous oxide making more horsepower than anyone would believe, with no clutch slipping. I run a Fox shock on the rear as they are easily rebuildable, and easy to tune.

Your suppose to use a dial indicator to measure how much Free play you have using a spare transmission shaft mounted in a vice. Reality is who is going to do this?? Kawasaki provides for three different thicknesses of the steel plates. Therefore aftermarket clutch suppliers do not know what you need for your specific application. The easiest way to get around this is to use 5 2.3 steel plates and 2 2.0 steel plates. Forget the 2.6 steel plates. This setup provides for the best feel and brings the back torque limiter closer to racing applications on downshiffting as well. The steel plates if you feel the edge of them with your finger will have one distinctively sharp edge and one smooth edge. Install them all in the same direction, though it doesn’t matter which way. This info is not in the shop manual, but is very important. Purchase a set of Barnett heavy duty clutch springs but only use three of them staggered every other one with a stock spring. This will increase your clutch’s capacity without making the lever pull to hard. The stock clutch friction plates work as well as aftermarket but are more pricey. When installing the friction plates the shop manual calls for aligning the last plates tangs offset from all the others. DO NOT DO THIS.
The overall thickness of the combined steel and friction plates will be less and the last friction plate will not be able to apply correct pressure to the stack. This is very important. Make sure you get the correct bolts back in the original holes when reinstalling the cover as some are different lenghts and be careful not to over torque as I have seen many stripped clutch cover bolts. Also you can reuse stock friction plates even if they are very discolor as long as they are not (WARPED). The discoloration can be cleaned off with scotchbrite and you can check for warp by placing them on a flat piece of glass, but i would just buy all new ones and get the 2.3s and 2.0s. HAVE FUN!

When your installing your clutch plates, look at what would happen if the overall stack was not thick enough, the FIRST plate could BOTTOM out in the offset notch and then no pressure would be applied to the stack. I’ve seen this happen before on a race bike at Road Atlanta that surely cost a racer a national title. That’s why the only correct way is to use the spare tranny shaft and a dial indicator. But in the real world who has one?? So if you are unsure, never use the offset notch. It does no good or serve any useful purpose to use the offset notch. Now, why does Kawasaki show this in the manual. I’ve asked this question a hundred times and nobody can give me a logical answer. I can only hypothesize it might start the release of the plates a little earlier or something like that. No one at Kawasakis Headqtrs knows the answer either. The clymer manual tells you to do it simply because they copy directly from the Kaw manual and don’t know no better. The second best way to do this is to measure the plates that were in there and reuse the same size if you are going to use the offset notch. However for the best feel and for what I think most of you are using your clutchs for are 5 of the 2.3s and 2 of the 2.0s all lined up in the same notch and have at it. This was the setup most racers were using in the 91-95 ZX7s. I have run this setup using nitrous without a problem and shifting with the nitrous ON using clutchless shifts and have never had a problem.

Ken W

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