best 400ex head gasket

[jdog75]

just got my 400 running and just blew a gasket. what do you think is the best gasket you can buy for an 11:1 416 namura lasted 24 hours so i dont think im gonna buy anything from them again. please help

[eprovenzano]

The gasket isn't the issue, with a high compression piston you need heavy duty studs.

[johnnynonails]

some ppl just dont read before they answer,shame.cometic is cool.

[jdog75]

ya i was thinkin cometic i have my head torqued to 45 and it still blew in a day. i was ridin nice and easy to on a frash rebuild and breaking it in and it still happened but is there a way to buy just the head gasket

[matt1106]

I may be wrong, but i think 45ftlbs might be too much 6torque for the head. its been a year since i rebuilt one, but i though the tourqe specs for the head was low to mid 30's. ill check my shop manual in a little. in my experiance 416's usually dont a problem with head gaskets, but any bigger they do. and 11.1 isnt that high of a compression, so thats not the prob. and ive had the best luck with cometic gasket kits for my machines. but for sum reason the kit does not include a gasket for the valve cover on the 400's im not sure y.

[F-16Guy]

Was the gasket a fiber one? I think those typically require a re-torque after a couple of heat cycles. What you want is a Cometic MLS (Multi-Layer Steel) head gasket. They are embossed stainless gasket layers riveted to a shim plate. The gasket layers are coated with Viton rubber to provide a perfect seal with no re-torque requirement.

Just out of curiosity, who installed your GTT studs?

[rob_990]

were you jetted right?it coulda blew cause it was running to lean and for the replacement gasket go to you dealer and get one from an xr400.there thinner so it raises the compression

[jdog75]

a local shop installed them for me and its running a little rich but no that bad

[F-16Guy]

Originally posted by jdog75
a local shop installed them for me and its running a little rich but no that bad
Did they use a roll form tap? You may want to find out. If the studs are good and the gasket surfaces are flat, get a Cometic MLS head gasket and put it back together. Don't overtorque the nuts. I think I torqued mine to 35 lb-ft and haven't had an issue for years with my 11:1 piston.

[jcs003]

cometic are good. but i would recommend an xr400 gasket with a good spray gasket sealer on both sides of the gasket.

[jdog75]

i am taking apart my 400 now and the gasket just didnt seal right at the one rivet. but i found out it wasnt toqued to 45 but 35 my bad but is there a specific torgue i should run for my new setup (in sig.)