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freestyle111

WR valve Problems

16 posts in this topic

I hope its human not technical error :thumbsup:

non adjusted valves, lack of coolant, oil, to lean air/fuel mixture?

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Been there done that! Nows a good time to throw in a 13to1 comp. piston, fresh valves, valve seals and valve retainers.

Maybe some new grips on the bars because you'll need them when you light off that 13to1 piston. One of my intake valve retainers let loose and made my piston look like yours. I now have over 2000 miles on this rebuild and still runs new. Great power! Good luck! :thumbsup:

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that there is some ugly sheeeiit!!! sorry, man. what year is that? do you remember any neglect? have you called your yamaha dealer? i'd love to hear what your dealer has to say.....I once heard a Husky dealer help out a newer TE 450 owner with getting him new valves....his went after 10 hours.....

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i put over 4000 miles on this motor since last rebuild.

Nows a good time to throw in a 13to1 comp. piston, fresh valves, valve seals and valve retainers.

take another look at that piston.its 97mm [444cc]13.5:1 As for cause of valve failure its hard to say.Valve clearance was within specs last time i check[which was about a month ago]my bike has CA.license plates so i put alot of miles on motor this summer.I was on freeway cruising about 70mph when motor blew.With 15\45 gearing motor is only reving about 4000rpm at 70mph.I think gas might of contributed to valve failure most of time i Run Cam2 110 octane but recently i've been running pump gas 92 octane.

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That hole in the center of your piston is usaly caused by detenation. runing a 13.5to 1 compresion rato on pump gas dosn't sound like a good idia to me. I,m am thinking this is what cause your engin problems. If any of yall have an engin set up like this that runs okay on pump gas pleas corect me. I was considering the same mods when it comes time for a top end job, but after seeing the photos of your head and piston I think I will be stiking w/ stock compreshion

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Hey I'm no longer a newbi,YEAY! any ways i forgot to ask you if you were useing your stock heat range spark plug, cr8e. If you put in to high of a heat rang this could have caused your problem. alot of carbon build up on top of the piston could have caused it as well. I said it was caused by detination, I ment pre ignition.

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Heheh. I think the hole in the center of the piston was caused by the valve head embedded in it.

I think Oasis_Flame nailed it - failure was probably caused by valve keepers coming loose.

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Heheh. I think the hole in the center of the piston was caused by the valve head embedded in it.

I think Oasis_Flame nailed it - failure was probably caused by valve keepers coming loose.

Don't think it was the keeper. Looks to me like the valve head broke off the stem. Common problem when these titanium valves are stressed. When it happened to mine (1,400 miles on motor), it destroyed all 4 remining valves, the piston, cylinder, rod and crankshaft.

Send the head off to EdCo, Mike can fix it. Along with his labor, you are looking at about $500 for new valves, seals, amd guides. Damage to my crank was at the cam chain drive gear. It bent the teeth and of course damaged the chain also. You need to check that and make sure the rod is not bent.

Sucks, but that's the risk with these high performance machines.

x2

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valve keepers didnt come lose.valve stem broke about 1\2" above valve seat.broken stem ,keepers, valve spring and bucket are still together.

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Ah. I see the straight valve stem in the pic now.

Aren't those valves made of two different types of metal fused together?

Looks like it failed at the fused joint.

Is that head salvagable? Looks pretty chewed-up.

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Yes, appears the valve has broken at the stem. I've seen this before with 3 piece valves. The head, stem and retainer end were all 3 different parts. I'd be willing to bet the titanium is only the valve tulip end, with steel elsewhere, making for a "splice" which is where it probably came apart.

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