Clutch Slip on 99WR400

A clutch on a 4 stroke will virtually last forever as long as its not abused excessivly.

Ive bought my 99 WR brand new and the clutch has never slipped, not once. And I have at least over 200 hours on it.

Changing to heavier springs might be a good idea. You might have a slightly heavier clutch pull, but oh well.

Anyone seen their 99WR400 clutch start slipping?

my bike has maybe 70hrs on it and the clutch started slipping slightly. I purchased new fibers which are Barnetts. Interestingly, the brand new fibers were slighly thinner than the stock ones I pulled. As I dis-assembled the stock clutch, I was amazed at how mint it was. (practically brand new) Having spent the $80.00 on the new ones, I put them in just for giggles thinking the stock ones may have been glazed. End result, the clutch still seems to slip. I'm thinking new springs also but I'm still amazed/confused over the pristine condition the old clutch was in.

The mechanics that I have talked to say when it comes to clutches stock is best. I change mine every spring and save the old plates just in case I ever fry a clutch. It came in handy when I fried the plates in the mud on my YZ.

Back to the clutch slipping. If the play is correct in the lever, the cable is clean and lubed, fiber plates are new, and it still slips then you are down to either the springs, or the pressure plate. You might want to try measuring the metal plates to see if they are with in specs. Personally I would trash the Barnett fiber plates and get some stock plates. That is how I had the conversation about stock is best , right after I had the conversation about how to get broken plate shrapnel (Barnett) out of my motor.

Did you check the basket for grooves? You can remove them with a file if they are not too deep.

New springs are always a good idea and I have also heard that stock plates are best.

Have you changed you're brand of oil?

Make sure you have some play in the clutch cable. The type of motor oil you use can also affect the clutch. I ran my 400 for two years before changing the clutch plates. I abuse the clutch tremendously and was suprised to see the clutch disks still in mint condition. the only time my clutch slips is when i adjust the cable too tight. Then I promptly readjust till there is just a minimal amount of play in the cable and voila no slip grip. I run synthetic motor oil with no problems so far.


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