Countershaft seal issues

July 2009

NOTE: I thought my local hardware spot was an Ace Hardware.

Turns out it's a Tru Value Hardware, and they're not the same!

Apologies to anyone who tried to find the parts at the wrong place.


The countershaft on a 565 KTM seals in 2 places. The outer seal is a standard arrangement and usually is not the source of the leak. The inner seal is an o-ring seal, is not a dynamic seal, and is what usually give people the most problems. The following pix will show how the thing works, and will show the best fix I've found.



Here I've removed the countershaft sprocket from a parts bike engine.



You simply grab the spacer by hand and pull it out of the outer seal. It's pretty straighforward to replace the outer seal. Many times, the folks that ask me how to fix the freakin' countershaft leak have already done this, and they have cleaned up the sealing surface of the spacer. These things may need to be done, but the tricky part is the inner seal.



Here is the inner sealing surface. It presses an o-ring against the bottom of the shaft. This seal has to be good too, or you'll have oil coming out at the countershaft sprocket.


Here I'm fishing out the o-ring. This bad boy is usually the problem. You clean the shaft with a q-tip, clean up the inner sealing surface on the spacer, put in a new o-ring, and the next day there is that danged oil spot under the countershaft sprocket. Argh!!


May I introduce you to the cure. Simple as the day is long. Tru Value Hardware stocks these, if it's a good store. The stock o-ring is simply marginal in this application. Factory new they always seal. A few years (C'mon, the 565 series went out of production close to 20 years ago!) later and it just doesn't do the job. Install the 24x2.5mm o-ring in the usual position. Put on the spacer, the sprocket, and get the cir-clip on the shaft. You'll see that it won't seat because the new o-ring is holding the sprocket up too high. Good. That's what we want. Now take a large flathead screwdriver and a mallet and gently tap one end of the cir-clip down into the groove. Work your way around the shaft until the cir-clip is completely seated. Done!


Now, tomorrow morning, there will be a DRY spot where you expect to see oil! ;-)