250r side case gasket

[leager-n-ky]

Hey guys, I have put together an all new motor, new case halves bearings, seals, etc. The problem I am having is the side case gasket keeps " blowing out" it runs for a while with no problem, then starts leaking in behind the radiator hoses above the water pump. I have had some people tell me to double up on the gaskets (install 2 gaskets together) Has anyone else had a problem like this?

[All250R]

You should have come to the conclusion that the problem isn't the gaksets but the aluminum. Getting the surfaces resurfaced or lapped is your answer... over doubling gasket surface that is. Then again RTV does wonders, but the permanent fix is to put a quick surface on the aluminum.

[leager-n-ky]

Well thats what i was thinking, but after you spend that much money on new case halves, and they didnt have any visable nicks, and the hinson quick change cover i have had for yrs with no problem's. I have a friend that says he knows of several 250r's that have done this in the same area(above water pump) and i have never heard of it. The only way to have pressure in the lower end is if the crank seals are bad, correct???

[ERBE]

Look into Cometic AFM I use them on all my Quads.
These are also some bad *** Base sealing gaskets

http://www.cometic.com/est.aspx

Cometic AFM material engine cover gaskets are made from a chemically blown compounded nitrile synthetic rubber that is bonded to an aluminum core. AFM material has a temperature resistance of over 250° F (121° C) and an 85% recovery while maintaining a strong torque retention. Gaskets made from AFM install dry and do not require a re-torque. Typical gaskets made from AFM include: cam chain gaskets, timing cover gaskets and water pump gaskets.

[2muchquad]

sealant works wonders if properly applied,i have used yamabond with great success.You'll have to let it set up before you join the halves for best results.i had a yz 250 that had the bottom of the cylinder pitted and it would go through base gaskets unitl..i used the yamabond;) cheaper than sending the cylinder off to get milled