Blown head gasket?

4 replies to this topic
  • tpastrana

Posted January 26, 2011 - 04:26 PM


After a good day of riding 9hrs or so. i stopped and realized the bike was running hot but the exhaust was normal and then i slowly saw the exhaust turn to a white smoke. I reached back and my glove was soaked with coolant i shut it off. My friend ran back to the truck got some water, started it and you could just see the water coming out of the exhaust midpipe. This is a newly rebuilt motor, and I still have good compression,. Is it likely that the head/base? gasket went bad? Pretty sure you cant install the gasket upside down.

Thanks any help is appreciated.

  • brentn

Posted January 26, 2011 - 04:37 PM


Sounds like it.

The lower gasket would allow coolant into the crankcase once the system is pressurized and hot, you'd probably have smoke billowing out the breather tube and coolant in the oil.
Sounds like it's just the head gasket itself and not the base, if it's not torqued in stage the mating surfaces between the head, gasket and cylinder will not be perfectly sealed.
I would take the head off, get yourself a new headgasket, and make sure that the cylinder mating surface and the head mating surface are perfectly flat. If they are, torque in stage the bolts according to the manual's specifications.
Unless someone else has a better idea. I've never worked on a 4 stroke top end before, just read enough to prepare myself for my own work down the road. Hopefully this helps.

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  • tech24

Posted January 28, 2011 - 06:24 AM


agreed tear'er back apart!

9hrs of riding? Is that even possible?

  • davecampbell

Posted January 28, 2011 - 06:34 AM


I don't have a surface plate so I use a thick piece of glass wrapped in emery paper to surface the head and cylinder. I am surprised how many heads look flat even with a straight edge but take a fair amount of lapping to get it totally flat.

  • tpastrana

Posted January 28, 2011 - 12:36 PM


agreed tear'er back apart!

9hrs of riding? Is that even possible?

Sure it is! We were geared up at 8:00 am took a lunch break at 12:00 got back out at 1:00 and rode till 5:30-6:00ish.

Totally slipped my mind that I definitely should of checked that before i put her back together, but at least she lasted all day. Couldn't of been a better day It was the perfect day 55 degrees most of the day. Maybe I will just take it to the machine shop and have them do it for me :thumbsup:

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