loud rattle

[christophere251]

I just recently put a 12.5 -1 440 kit in my ex. It has a stage 2 cam the carb was jetted to the specs in the kit. It runs fine has tuns of power starts with no prob. But the valves sound like they rattle through the midrange when its cold. If u warm it up for bout 20 -30 min u cant hear it any more. I tried some race gas and that didnt clear it up cause i was running 93 pump gas before and figured it was detonation. Another weird thing is that it did nt start to do it until after about a week worth of riding. Could it be the jetting or what i am baffled. Another thing is the valves are set to spec so there not out of adjust ment either. Any help would be great!

do you have skid plates on? if so are they loose?

[christophere251]

nope no skid plates! its comin from the topend!

[christophere251]

its a blown head gasket yall! I could see some stuff comin out arond it yesterday. When it heats up it seals good but when its cold it leaks that was the noise i heard!

[Ncboost]

What kinda head gasket do you have?

Sounds like time for some heavy duty head studs.

[crewworrior]

im having a similar problem mine just started to smoke and have a loud rattling noise i also checked my valves and there to spec.the only thing out of the ordinary that i can find is that theres some oil coming from the valve cover like there may be a broken gasket,and the intake boot is junk when you throttle hard it will try to backfire through the carb,the noise im hearing sounds like a really loose valve.thanks for any help that you provide.oh yea mine is a stock bore 400ex

[christophere251]

im using wiseco brand gaskets but fixin to replace with cometic!