Cracked Clutch Case

gshaus · Apr 14, 2003

I have a 96' KDX 200. I was riding over the weekend and when I loaded my bike into the truck I noticed that the clutch case was broken. (the case with the little window for viewing oil level). The crack was in the top 3/4 of the case and was not huge, but large enough for oil to leak out. I am not sure how long I had ridden with the crack, but the bike ran fine, and I experienced no problems. What type of damage could there be? What should I look for? (clutch slippage, etc). What repair recommendations should I follow other than replacing the case and the gasket?

beefking · Apr 14, 2003

In my old bikes we have used JB Weld to seal the cracks/holes up in cases and covers. Its a dual-part compound that you mix up, dries in about 24 hours. It sets up to be very hard, you can even drill and tap it thats how strong the stuff is. Just need to clean the area up real good before applying with brake cleaner.

Dirt may have gotten into the tranny, so obviously drain the oil and check it to see any metal filings or dirt particles. Also check your clutch plates for grooves, caused by the dirt. If everything checks out its an easy fix. ;)

m0rie · Apr 14, 2003

I second beefkings suggestions. I rode around for quite a while with the sight glass cracked on my clutch case. Didn't hurt a thing. Just drain the tranny and flush it out with new oil. Lather, Rinse and Repeat for added protection from the elements :-)

BRush · Apr 14, 2003

Here’s something new to worry about. Closely inspect the sight glass. Did it look like it cracked from the outside or from the inside? A moderately common problem on a KDX is the “governor” rod or “centrifugal advancer” lever failure. This is a pin that’s part of the kips system located behind the right sidecover. For a number of reasons, the pin can break. Then it will rattle around in there causing damage. In at least one instance reported here, the symptom seen by the owner was the oil sight glass cracking and leaking for no apparent reason (later seen to be because the pin had ricocheted off it from the inside).

The two most common reasons for this are:

1) The advancer shaft not properly supported when the left hand nut is removed when doing a top end.
2) Top end maintenance is neglected for a long period of time and the power valves become gummed up to such a degree that they put stress on the pin causing it to fail.

MX175 · Apr 15, 2003

gshaus, My guess is that the bike fell over and the side case landed on a rock or something and that caused the crack. But, if something broke inside and cracked the case from the inside, that will be more significant because you should determine what may have caused the crack from the inside.

The case repair is easy with JB Weld. It is available everywhere, even many grocery stores; Wal-Mart, K-Mart, Auto Parts, etc. If you haven't used it before, you will be amazed.

Hopefully, the crack shows some indentation or adjacent scratches that verify it was an external impact that caused the crack. But if that crack is bowed or blistered outward, you need to take a good look inside. Good Luck and let us know.

gshaus · Apr 15, 2003

The replies have been great. MX175, I think you are right about how the crack occurred. I had a little mishap going up a hill climb, and the bike fell on its side. Unfortunately, the crack is a little larger than a "crack". There is actually a small hole where the case broke open, on the top 3/4 of the case. So i guess I will have to fork over the $$ for a new case. If this is all I have to spend then I will be very happy. :)

MX175 · Apr 15, 2003

Even if you can fit your finger through that hole, I would try JB Weld first. Of course you should take the side case off so that you can get to both the inside and outside. Maybe use something for a backing so the JB Weld doesn't "drip" toward the inside. If you sand it up nice and repaint that case, you should not be able to tell it was repaired.

If you don't like the idea of doing a repair, I would look on eBay or contact Jeff Fredette at www.frpoffroad.com to look for a used one. I hate to give money to the dealer.

gn83tm · Apr 15, 2003

I would agree with the suggestions on repairing it with JB Weld or some other 2 part metal epoxy. I remember when my neighbor drove the shift shaft on his old RM right out of the right side cover. It made a hole about 2 inches square and to make matters worse he lost the piece that broke out. I cut a piece of aluminum out of an old grain scoop and put it in with JB and it worked out well. We sanded it down and painted it and you had to look real close to tell.

I also have a Briggs motor on my power lawn rake that is held together with JB. I kind of "slipped" with my hammer when I was tapping on the base of the crankcase to adjust the chain. The hammer went right through the case so I took it apart, pushed the pieces somewhat back into place, cleaned things up, and JB'd it. Hasn't leaked a drop in about 8 years.

Good Luck!!

MX175 · Apr 16, 2003

So gn83tm, do you do much maintenance on your neighbors machines? I'll bet not with your careful 'tapping' ability. I used to let a friend from work do a lot of service on my machines, but he was such a gorilla, I could hardly remove any of the nuts/bolts he tightened.

gn83tm · Apr 16, 2003

MX175
If you notice, I said it was my "neighbor's" carefull tapping ability that did the damage to the RM - not mine. I'm the one that fixed it.

I will however take credit for the little problem with the Briggs. In my defense, I just want to say that I'd been working on that rotten thing for half a day trying to get it running. It was 100 degrees with 98% humidity and the last thing I wanted to be doing was working on a cranky "tater digger" engine. That thing is lucky I didn't get the really big hammer and smash it up so you'd need a concrete truck full of JB Weld to put it back together.

Actually, only needing JB Weld twice in 25 years is pretty good, I think!

Cracked Clutch Case

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