400ex help

[dilligaf29]

im just about done rebuilding my 2003 400ex and i noticed i have a o ring left only place i came up with was i forgout to put the one for the cylinder O-RING, CYLINDER (88X2) do i need to tear it down to put it in or can i go ahaead and finish the build i was at the point of putting the valve cover on this is a new jug piston rings 440 big bore thanks

[Stickman400]

If it is in fact that big O ring on the bottom of the cylinder I'd be very hesitant to run it without it. I can almost guarantee it will leak, if not immediately it will down the road. I'd err on the side of caution and put it on while you are doing it now, instead of beating your head against the wall later wishing you had done it now. Sucks to have to tear it back down but it's for the greater good. THE GREATER GOOD! lol:p

[dilligaf29]

thanks i will tear it back down id rather it be done right then have to fix it down the road sense i took the bike apart painted frame and replaced almost all the worn out stuff can i use the head gasket again it was brand new but not sure if i can use again or buy new one

[Stickman400]

If you haven't even gotten it put together yet then you should be able to re-use it. The valve cover gasket can also usually be reused as long as it doesn't have anything wrong with it visually.

[dilligaf29]

i had it all together was at the last part torquing valve cover down when i relized i misted that o ring o well learning experince was my first top end i ordered a new gasket kit today i was looken around today and some one did same thing didint put the o ring on the jug i think his lasted hhalf a run and he asked about head gasket and some one stated would u re use a dirty condom after that line i placed the order better safe than sorry thanks for the info