20 Most Recent 2008 KTM 250 SX - Page 5 Questions & Answers


It's a bad seal of the head gasket. You need a new head gasket and to scrape every particle of debris from the cylinder head and cylinder surfaces that mate with the head gasket. Use the factory specified gasket sealing compound and do a clean job - no blobs or pools of the stuff. The head gasket should lay flat on the surface of the top of the cylinder, and you have to make this surface free of grit, leftover sealant and any other foreign matter before you put the head in place and torque it down. Start with the head bolts just finger tight and then go by the manufacturer's specs for the pattern and amount of torque to be applied. Usually it is recommended that you get to the specified torque amount in stages, going around several times and repeating the torque pattern until you get that maximum rated amount. This will prevent the seal from shifting or warping and should make the gasket seal perfectly. This is the old school method of doing this job. and I have never seen this fail to produce good results. Take your time, be clean, and you will have the results you want.

KTM Motorcycles | Answered on Dec 31, 2018


over full sump
fuel getting into sump
badly worn rings allowing excessive blow by

KTM Motorcycles | Answered on May 05, 2018


Make sure cables are working . Follow it down to clutch and make sure clutch lever is actually moving. It is does then pull clutch in and pushbike backwards. Should release If not , plates are probably frozen through excessive heat. Replace them. If lever does not move when clutch handle pulled, then adjust or broken cable. hope that' it, easier and cheaper!

KTM Motorcycles | Answered on Sep 24, 2017


Have you tried an emissions test? That can tell you a lot about how the combustion is doing, and what you would need to adjust at the carburetor. Have you checked the spark plugs?

KTM Motorcycles | Answered on Jul 26, 2017


unfortunately the most cmmn cause for a bike not starting ff the kick start but starting with a bump is being too low on compression,although to you foot it may feel like enough it does need to be nearly 100% as high as it should be to kickstart.the easiest way to check the condition of the piston is to take the exhaust off and look up the port in the barrel ,it is usually the exhaust side of the piston that gets damaged as it gets hotter.good luck.Adam

KTM Motorcycles | Answered on Dec 24, 2016

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