ASK THE MXPERTS: MYSTERIOUS KTM 350SXF OIL LEAK

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Don’t remove that countershaft so quickly, your leak may be something simple.

Dear MXA,
My KTM 350SXF has a persistent oil leak at the countershaft sprocket. I have searched everywhere for the source of the oil, and my dealer says it is mist from a small access port in the back of the ignition cover, but I have siliconed that up and the oil keeps appearing. Where is it coming from?

It’s not your countershaft seal. It is you clutch slave unit. This isn’t an uncommon problem, but you should try tightening the bolt that holds the black plastic countershaft sprocket chain guide on. The top bolt does double duty in holding the countershaft guard in place and securing the clutch’s hydraulic slave unit to the engine. If it comes loose, oil can leak out of the hydraulic slave unit down onto the countershaft sprocket. The solution is to check the countershaft guards’ top bolt at regular intervals. Additionally, oil by the countershaft sprocket can be traced to a countershaft seal leak, loose clutch slave unit or, on the 250 and 350SXF, the blank plug on the ignition cover.

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