Valve failure

3 replies to this topic
  • Racing227

Posted March 22, 2005 - 09:11 AM


Yes, it happen to me :) 1 intake valve broke and the other 4 are bent... It will take complete cylinder head, 5 valves, piston, connecting rod, crank pin and rod bearing. About 2000$ ( Can ) of parts. My dealer will call Yamaha if they can do something for me. I let you know what happen when i have news.

I have pics but no place to store it :)

  • Oouthere

Posted March 22, 2005 - 09:22 AM


Sounds like it jumped timing or the crankshaft/rod bearings got sloppy. Hate to hear it.


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  • Racing227

Posted March 22, 2005 - 10:50 AM


No jump timing. And no problem with rod bearing and crankshaft.The valve just broke at the bottom of the stem, just before the head of the valve. If you have Dirt Rider, check in the february 2005 issue: Valve trains part 2 and you notice that OEM valves are 2 pieces part: a cast head that is inertia welded to a stem rod. And when they break is usualy on the stem next to the weld.

For those who don' t have Dirt Rider, inertia welding involves spinning the stem and head in opposite direction at high rpm and merging the two pieces together with pressure. And in the January issue, valve trains part 1, they said that valve trains part break for five main reason: metal fatigue, lack of maintenance, dirt contamination, loss of lubrication and riding error. The most common is metal fatigue. In my case, i think that my valve spring may be to weak .....

  • Oasis_Flame

Posted March 22, 2005 - 12:35 PM


Racing227, been there buddy. Two years ago mine blew its gourd. It cost $1200.00 bones in just parts, I did the rebuild myself. I now have 2000 miles on the motor with no problems. is where I found the best prices. Good Luck...


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