Head gasket leaking need help! Also XR or EX gasket??

[ranger400ex1994]

Head gasket leaking need help! Also XR or EX gasket?
I have a 2002 400ex that i just had motor work done to it in february with a 11:1 compression wiseco piston and a old stage 2 hot cam plus MX porting.the gasket set i order came off ebay so i'm sure it was not the best. Know i have never took my head off before but i would like to learn how. If someone could tell me what the best way to remove the head is and what else i will have to take off. Also whats the order i would have to torque the head bolts at. and how much torque do i use?. I was also woundering if I should get a XR gastket or just get a EX one i heard that the XR will give me the true compression of my piston.

Also when i rev the motor up there are bubbles blow out of when the gasket meets the cylinder.

[2004exrider]

if u got it off ebay its more than likely its a wiseco, es get xr gasket thats what they base the true compression on. not a whole lot of diff though 400ex compression ratio 9.1:1
xr400 9.3:1

[RiderTRX400ex]

get a service manual from honda, everything u need to know and got all the torque specs:D

[jhoppa]

I just replaced my head gasket 2 times on my 416ex. My suggestions

1) Get a service manual (trust me)

2) I was told the only reason head gasket fail is because you over-heated the engine. When this happened it also pulled out the stock studs and this caused the head gasket to leak. (Given you had engine work done, I would bet your studs pulled out.)

3) Cometic makes an AWESOME head gasket. Viton/and full stainless steel sandwiched between. Much better than the stock gasket.

4) Save yourself some time and anger... Replace the studs and head gasket. I bought the GT Thunder studs. Call him he is very knowledgable on 400ex's and overheating.

www.gtthunder.com ??

5) Have Patience, it is a pretty easy job to do if you have some mechicanical skills.

6) Don't strip any of the bolts- take your time

7) Don't skimp- Use assembly lube, and permatex sleev retainer (might be hard to find, locally)

8) Race Gas??? With this high compression piston, it will run cooler with race gas.

[ranger400ex1994]

How will i know if i pulled a head stud out? will it just pull out when i take the head off or what?i really barely rode the thing i mean i rode it in the winter alittle and on the MX track once this year. I never really got it really hot.

[jhoppa]

Yeah, I don't know how you would tell. More than likely if it did pull it would only pull out .001-.004 thousands. Enough to make a head gasket leak. Could have stretched the studs or pulled them out a little in the cylinder.

I was told by GT Thunder that the only reason for a head gasket to fail is because of the studs pulling out. He has never seen a gasket just blow out by themselves.

Given the compression you are running, and the work done to your engine, I would say good chance you pulled the studs.

I replaced the head gasket ONLY once, made one lap on a harescamble and it failed.

Put new studs in and head gasket and have not had an issue since.

Good luck

[khen]

If you try to torque down your head(37lbs) and it won't hold torque, or it does hold torque for a while but the cap nut(s) become loose again over a short time then you've pulled some or all of your head studs. Mine did the same thing recently. :(

[ranger400ex1994]

khen did you have to get HD head studs? also will it hurt anything if i just run it as is?

[khen]

I haven't done anything with that cylinder yet, I just threw on my 400 bore spare cylinder until I can get around to ordering and putting in the HD studs.