blown head gasket?????

8 replies to this topic
  • nagualchrist

Posted April 14, 2004 - 06:39 PM


i hope that i am not the first failure with the 450 cam swap but i know that coolant out the breather hose is a very bad thing. is there anything other than a blown headgasket that would allow the mingleing of these 2 incompatable fluids? bike was running great other than an oil leak out of the decompression plug. maybe the oil got too low and the gasket fried. how big of a job is it to change out the head gasket? :)

  • sirthumpalot

Posted April 15, 2004 - 01:19 AM


If your inner water pump seal went bad then that would also allow coolant into the oil. I would check that first simply because it's easier to check and easier to fix.

  • rbsdsu

Posted April 15, 2004 - 04:57 AM


Yup check the inner water pump seal but if its not that than most defintely a head gasket! I had the same problem about a year ago!

  • nagualchrist

Posted April 16, 2004 - 09:24 AM


how do i get to/check it?


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  • trailriderjoe

Posted April 16, 2004 - 09:33 PM


Pull off the RH side cover (the big one), not just the water pump cover. The shaft and impellar assembly will come off with it. Get into your service manual, it shows a real good picture of how to dis-assemble the water pump shaft and seals. Non of which is a big deal to work on, minimal tools needed. The shaft (if bad) is around $25, the seals are about $5-6 each, and don't forget a fresh side cover gasket.

Once you get the cover off and get impellar off the shaft you pull the shaft out towards the inside of the cover (it slides right out). You'll have to push / pull the little bearing out to replace the inner seal, but the outer seal is a joke, it pops out with a smaller screw driver.

When the outer seal leaks water just runs out the weep hole down under the side cover. When the inner seal leaks, the water runs into the side cover (thru the bearing) and into the oil.

Once you get the seals out it'll be obvious (usually) which one doesn't seal to the shaft worth a crap. You can usually see where the sealing lip is worn out. Even if not at that point at least replace both the seals, the shaft is supposed to have a step in it, but not any "grooving" where the lip seal rides on it.

  • Satch0922

Posted April 17, 2004 - 03:10 AM


check the water pump seal. There is nothing involved in the cam swap that would cause a blown head gasket. If you mis timed the cams it wouldn't start.

  • nagualchrist

Posted April 17, 2004 - 08:02 AM


got the seals changed, inner seal looked as though it had been binding, kinda wrinkled. is the seal self lubricating?
hopefully this solves the problem as i dont want to tackle the head gasket.

thanks :)

  • trailriderjoe

Posted April 17, 2004 - 08:11 AM


Trust me, if you did the cam you can do the head gasket. Putting the cams in BY FAR is the hardest part of doing a head gasket.

But, it sounds like you found the problem, if the inner seal looked a little off. Yes it is self lubricating, notice the ball bearing inboard of it was not sealed (no lip seals on the cage), that lets the oil pass thru the bearing and get to the lip seal.

  • TonyDeCoster

Posted April 17, 2004 - 10:44 AM


Sometimes the seal "sticks" to the housing if the bike hasn't been ridden for a while. ...

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