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grond

'07 wr450f compression problem

8 posts in this topic

10 hours on the bike total. Did most of recommended mods. Starts making a clacking noise coming from the engine area. Then had no power under acceleration, but idled fine. The dealer did a compression check, say I have 12% blowby at the piston, Yamaha says 10% is the max.

What the hell, this is a brand new bike! Dealer wants to tear it down and see whats up, probably can't count on Yamaha for any help.

1) Does this sound familiar to anyone?

2) Has anyone had any luck in getting Yamaha to step in after the 30 day warranty period, especially with less than 10 hours?

Thanks in advance,

Greg in Chandler, AZ::cool:

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10 hours on the bike total. Did most of recommended mods. Starts making a clacking noise coming from the engine area. Then had no power under acceleration, but idled fine. The dealer did a compression check, say I have 12% blowby at the piston, Yamaha says 10% is the max.

What the hell, this is a brand new bike! Dealer wants to tear it down and see whats up, probably can't count on Yamaha for any help.

1) Does this sound familiar to anyone?

2) Has anyone had any luck in getting Yamaha to step in after the 30 day warranty period, especially with less than 10 hours?

Thanks in advance,

Greg in Chandler, AZ::cool:

maybe it didn't break in right and the rings didn't seat. thats too bad man.

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10 hours on the bike total. Did most of recommended mods. Starts making a clacking noise coming from the engine area. Then had no power under acceleration, but idled fine. The dealer did a compression check, say I have 12% blowby at the piston, Yamaha says 10% is the max.

What the hell, this is a brand new bike! Dealer wants to tear it down and see whats up, probably can't count on Yamaha for any help.

1) Does this sound familiar to anyone?

2) Has anyone had any luck in getting Yamaha to step in after the 30 day warranty period, especially with less than 10 hours?

Thanks in advance,

Greg in Chandler, AZ::cool:

I have not heard of any problems such as yours however, the order of business is for the dealership to do a tear down and find the problem and then contact Yamaha. And, yes Yamaha does step up in most situations!

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I agree with the possible poorly seated rings causing too much blow by. The problem with the engine clacking you mentioned doesn't sound like rings though unless a ring land on the piston broke. It could also be a valve hung up. This may not be related to your problem, but one thing I see alot of 4 stroke owners doing is washing the bike and putting it away. Whenever the engine is off for an extended length of time, I recommend using your hand to stroke the kick start lever to the spot in the engine that feels a bit tougher to go by. This should put your valves all in the closed position. The part about washing and parking the bike may leave the valves open with moisture in the system ready to seize the valves in the open position. Always run the bike after washing and then set the engine to TDC before putting the bike away. My rant-:cool: -WR Dave. PS--Whatever happens, please let us know!!

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10 hours on the bike total. Did most of recommended mods. Starts making a clacking noise coming from the engine area. Then had no power under acceleration, but idled fine. The dealer did a compression check, say I have 12% blowby at the piston, Yamaha says 10% is the max.

What the hell, this is a brand new bike! Dealer wants to tear it down and see whats up, probably can't count on Yamaha for any help.

1) Does this sound familiar to anyone?

2) Has anyone had any luck in getting Yamaha to step in after the 30 day warranty period, especially with less than 10 hours?

Thanks in advance,

Greg in Chandler, AZ::cool:

Dude you might get lucky with this one. First let me say that the first time that I ever adjusted my valve clearance I had the airbox cover and filter off of the carb and heard a loud clack like a spoons tapping when I fired it up. I almost crapped my pants thinking that I had a valve bangin the piston or something. So I did some reading and it turns out that the carbs on these things are loud as hell which leads me to my hypothesis. When I first got my WR I went ridin and had some of the same no power on accel issues you mentioned. Rode for a few then she gave up. Once again I almost crapped my britches. Thing was like brand new (minor mods which made me nervous). So I bust out the tools and start checkin wires and spark plugs and stuff on the fly. Just when I was about to give up, I noticed that the boot on the carb had slipped off so I put the toilet paper back. So if you're waaayyy lucky check the boot on that carb to see if its loose. It shouldn't be free to rotate if its sealed since its got a key that lines it up. Although, 12% blowby is bad. I hate to be this way but I know a couple mechanics and they'll snow anybody if they think that they can get away with it and make a few benjy's. I would check that compression myself against specs man...:applause:

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