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

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.

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Mods that I have done to my XTX's

My 04 XTX
Stage 1 & 2 DNA filters / Kev fuel mod / snorkel mod / Drilled air box mod / Engine breather mod / Fork Spacer mod / 15w fork oil /
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My 07 XTX
Raptor 700 cylinder 102mm / Modified Crank Case to take a 105mm Raptor Cylinder / 11:1 102mm JE Raptor piston / Stage 1 Raptor Hot Cam / Ported head / Colder Spark Plug / +2mm Throttle body / DNA stage 1 & 2 filters / Modified Air Box / Snorkel removed / Worry Brothers stage 2 filter cover / 6mm & 8mm Bolts Replaced with Titanium Bolts / Recovered seat in Black / O2 Eliminator /

My 09 XTX
59HP at the rear wheel / Stage 2 Raptor Hot Cam / DNA stage 3 Air Box / Carbon Can Exhausts / Modified Exhaust Link Pipes / PCIII With Custom Fuel Map / Wideband Commander O2 Data logger / LCD100 Dyno Jet display & fuel adjuster / 2500 OHM HT lead instead of a 10K OHM XT lead / Extra Coolant Cooler / Protaper Fat Bars / Tail Tidy With LED Tail Light / OKE Protection Knobs / LED indicators / AIS blocked / Modified rear sprocket rubbers / Rear Foot Pegs removed / 09 ECU With 02 Sensor Changed To A 06 ECU / Complete wiring harnes Changed from 09 to 04 / Home made LED resistor flasher / Hole drilled in the fuel tank filler neck to allow quicker filling / Modified Bar End Weights / Progressive front fork springs, 15W fork oil, forks lowered 25mm, used XTR rear links lowering the rear 20mm, rear spring one click stiffer / Changed front & rear guards from blue to black / 47T rear sprocket / Speedo Healer V4.0 / Kev throttle cam mod / Throttle grip mod / The new 2010 O2 sensor mod is out, works a treat, The new 2012 O2 Controller is out, PM me for details

Now ride a 2018 MT09SP ABS + TCS

My KTM 990 SMR Mod book. http://www.ktmsmt.com/viewtopic.php?f=13&t=4946