Help! oil leak!
 

Hello,

I Need help as not sure what to do next, I recently purchased a 2008 xt660z. Great looking bike rides superb and lots of toys(was also for sale on this site). I noticed on the ride home that I had slight oil marks on my leg, after some investigation I found that the base gasket is leaking.
So I pulled out the engine and removed the barrel . all nice and clean inside the bore.

BUT evidence of some one using a file on the sealing face of the engine cases. I tried to smooth these out with some 600 grit wet and dry with a flat piece of wood. Looked ok so put it back together and run it up.

Its still leaking!

I am confident I put it back together correctly with the right torque settings, clean gaskets etc. I didn't use any sealant. was this a mistake?
How do I flatten the surfaces so they seal?

Thanks for any advice, This is turning out to be a costly purchase!

Dan:violin:

Alright Dan.
When I've done facing work in the past I use a piece of plate glass with at the most 600 grit emery paper on. Plenty of water and a light action. You should be able to see any low spots show up quickly under a light.
I don't use any gasket sealer, rather a light smear of CL grease on each face and then the gasket.
I hope you get it sorted. A file? Eek.

Fixed it,

Made a gasket out of 600 grit wet and dry, stuck this to the barrel with double sided tape.
Lapped barrel onto block with a rotating motion.
small amount of sealant.

Went out yesterday for first proper ride since buying bike and loved it! 250miles with no problems with some mild green lanes.

Fantastic bike.

I would get the casings machined & the face of the cylinder checked for warpage, then run two base gaskets or a thicker base gasket if needed to make up for the material that was machined off.

I know when I decked my raptor 700 11:1 piston I could lower the cylinder by 0.30mm to get the correct deck height.