Oil around gearbox - possible leak?

11 replies to this topic
  • piercebronkite

Posted April 22, 2011 - 08:50 PM


I was about to do an oil change on my 2008 250XC and noticed a bunch of oil/sludge around the gear box. Could this be some sort of leak? Oil seems to be all around the gearbox case. I havent dumped the oil out of it yet since I ran out of oil. Any ideas on what it could be? The last time I changed the oil I did not notice it and I did not use a torque wrench for the oil plug.

Any help is appreciated.

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  • ktmfred300

Posted April 22, 2011 - 11:19 PM


Drainplug gasket or clutch cover gasket would be two places to look at. Sometimes the clutch cover gasket will get sucked in. Use 3-Bond to hold it in place better.

  • Rider 41

Posted April 23, 2011 - 05:16 AM


And don't use the oil level plug to tell you when it's at the right level, it will strip out even with a torque wrench. Get a ratio-rite cup and use it to add the correct amount of oil.

Trust me on this one, I know from experieince :thumbsup:

  • WRF Woods Weapon

Posted April 23, 2011 - 06:15 AM


This happens to a lot of bikes today, the dipstick present a false oil level indication. Use a container to measure the correct amount and that should do the trick. Remember with the oil level too low it can damage the engine. and too much oil in any engine is bad news!!!!

  • 1st4stroke41

Posted April 23, 2011 - 06:37 AM


Too much oil in that bike won't hurt the engine, 2 stroke..Too much oil in a gear box will just puke out the vent.

  • piercebronkite

Posted April 23, 2011 - 06:39 AM


Thanks guys. Forgot to mention I dont use the the oil level plug as an indicator, I do measure with a ratio rite cup. I opened the plug just to see if there was any oil.

I will inspect the two gaskets as mentioned above. Just hoping it wasnt anything major.

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  • ktmfred300

Posted April 23, 2011 - 09:30 AM


It is the inner gasket that is the problem most of the time. Clean it up well and take a short ride it will be obvious.

  • JaysDirtyRide

Posted April 23, 2011 - 09:43 AM


I experienced this for the first time on my newly rebuilt '08 300 XCW.

I discovered oil seeping out from the clutch cover seal. Drained the oil; cleaned the mating surfaces; put a small amount of RTV along the bottom section; bolted the cover back in place; waited about 6 hours and filled with the requisit amount of oil.

All is good now...not a hint of leaking.

Clean up the bottom really good with carb/brake cleaner, etc. Try sealing the bottom section of the clutch cover with a small amount of RTV or something similar. Let it dry and then add oil to the tranny.

Check for leakage after a neighborhood test ride...no dirt...see if that fixes it.


  • ktmfred300

Posted April 23, 2011 - 09:52 AM


3-Bond is much better sealer than RTV. RTV will break down when it comes in contact with oil in a much shorter time. 3-Bond is semi drying as well.

  • ohioktm250

Posted April 23, 2011 - 09:05 PM


I had the same problem on a 2007 250 xcw. Just redid the inner clutch cover gasket and the outer cover o-ring. No more leaks. not a hard job, about an hour and/or 4 beers.

  • piercebronkite

Posted April 24, 2011 - 06:06 PM


Thanks for all the suggestions.

How difficult is it to replace this gasket? Im new to 2stroke engines so I dont have a lot of knowledge but not afraid to get in there and get my hands dirty and learn. If its too much for me I may take it in to my local KTM dealer.

  • zwr250f

Posted April 25, 2011 - 08:44 AM


Not difficult at all, I just changed mine on my 300. Gasket is very thin and wants to squeeze out if not careful. I would suggest as others to use a bonding substance along with the gasket.

I had 3 leaks when I bought the bike (used), finally fixed them all, engine is dry and pretty!


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