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Discussion Starter · #1 ·
2004 400ex

for the past few weeks i have noticed there has been oil going into the header pipe from the motor. i bought crush gaskets a few weeks ago but didnt have the motivation to put them on because it was only a tiny bit of oil before.

today i started it up, and much more oil was coming out, looked like a sizzling pan of bacon, and then burning when it got onto header pipe to make huge amounts of smoke coming off the header. the bike ran fine though. also oil is only coming out of 1 of the headers, not both.

i have the crush gaskets and will put them on tomorrow but i have a couple questions.

1. i cant get the old crush gasket off, what should i do? i tried to pull them off but i cant get them. can i use wd40 to help get them off or is that not good to get alittle dripping into the cylinder head?

2. could it be something besides the crush gaskets thats making it leak? if so, what

3. what could be consequences of continuing to run it like this.

thanks for any help!
 

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You can stack the crush gaskets 2 is the max i have done. The crush gasket in no way shape or form is going to stop your oil leak. All it will do is stop an exhaust leak. If the oil is coming from inside the pipe your quad would have to be smoking like a tunered diesel. If not it is most likely coming from the valve cover just above the header and leaking down onto it. And running it as is will just make a mess and if you dont keep up on oil levels you will ruin the motor. My .02


P.S. be very very careful when removing the header flange bolts. They break very easily and will need to remove the head and have a machine shop remove them.
 

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ok gotcha. yeah a few hours ago i realized that it wasnt coming from in the motor and it is coming from the head i think. i could see it going down the side of the motor where the head attaches to the cylinder head, i guess you call it. and then dripping on to the pipe and also down the atv. i just dont know how to stop the leaking. its not coming from valve cover though i know that because theres no oil up that high.
 

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ok gotcha. yeah a few hours ago i realized that it wasnt coming from in the motor and it is coming from the head i think. i could see it going down the side of the motor where the head attaches to the cylinder head, i guess you call it. and then dripping on to the pipe and also down the atv. i just dont know how to stop the leaking. its not coming from valve cover though i know that because theres no oil up that high.
I would check to make sure that the head studs are holding 33ft. lbs of torque? If so then you probably need to have the mating surfaces machined flat. If they aren't holding you're going to have to install the HD head studs that Jeff Snure sells. He has the machining rights to GT Thunder head studs.
 

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Then when you built the engine the mating surfaces were not machined. You can torque GT studs to 45 with no problems... 440 has nothing to do with it unless it was assembled incorrectly a leak is a leak no matter what the bore
 

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If your getting gt thunder studs installed a machine shop is in your near future. You can send your jug to jeff snure or have them installed by a local machine shop. Snure interlocking is 45 minutes from me so i drove there. Jeff is a really good guy. Extremely trustworthy. Studs are 60 bucks he charges 50 to install them. All my local machine shops quoted around that same 50 some alittle more but none were less.

Studs are only half the battle though. You will need to have both the jug and head decked or some people call it skimmed. Either way they make both surfaces perfectly flat. More than likely someone removed the stock nuts to quick and in not enough steps and it warped the head. Usually why they leak oil around the head gasket surfeces.
 

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Discussion Starter · #9 ·
So do i HAVE to get the new studs? Or can i just have the stock ones redone at a shop? This is quite alot of oil leaking are you sure its the studs? A few months back oil leaked but it was tiny tiny amounts and i torqued torque bolts to 33 again. I dont really know. I really dont wanna pay $110 for all this though haha
 

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Discussion Starter · #10 ·
If your getting gt thunder studs installed a machine shop is in your near future. You can send your jug to jeff snure or have them installed by a local machine shop. Snure interlocking is 45 minutes from me so i drove there. Jeff is a really good guy. Extremely trustworthy. Studs are 60 bucks he charges 50 to install them. All my local machine shops quoted around that same 50 some alittle more but none were less.

Studs are only half the battle though. You will need to have both the jug and head decked or some people call it skimmed. Either way they make both surfaces perfectly flat. More than likely someone removed the stock nuts to quick and in not enough steps and it warped the head. Usually why they leak oil around the head gasket surfeces.
So do i HAVE to get the new studs? Or can i just have the stock ones redone at a shop? This is quite alot of oil leaking are you sure its the studs? A few months back oil leaked but it was tiny tiny amounts and i torqued torque bolts to 33 again. I dont really know. I really dont wanna pay $110 for all this though haha
 

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Getting stock ones "redone" will do nothing. The studs them selves are not the problem. The threads pull out of the aluminum cylinder they are in. The way gt thunder fixes the problem is you drill and tap bigger studs with coarse threads that hold up to alot more torque then the factory can. Just like before the stud being bigger is only half the battle. The different thread pitch and deeper threads that are drilled and tapped for are what makes the big difference.
 

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That and a good multi layer steel head gasket will do the trick. Once you get the mating surfaces decked. At that point it almost guarantees it.

And no problem! Always glad to help!
 
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