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poliisi2

Piston hours 450 2010.

13 posts in this topic

I would be curious what the manual says on this.....especially since this is a 4valve motor vs the traditional 5 valve motor...

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Dave, Per Yamaha Tech it is 15 hrs! this was the topic last night with the Yamaha rep after a couple of Jack and Cokes.

Tim is that you? Were you with whats his "Yami Reps name" from Atlanta?

interesting 15hrs.....what else can you share....the good the bad and the ugly....

Hope all is well man with you and your family ... happy holidays

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15 hours is what the manual has said for years, and for at least that long, it's been a ridiculously low number compared with reality. The real answer depends on exactly how the individual bike is used. A top pro racer is going to get considerably less time out of his engine in general than a purely recreational rider, an occasional racer, or even a fast amateur.

YZ450 pistons have mostly been good for at least a season except perhaps for the very serious racer. I ran my '03 on it's original piston until I sold it at the end of '07, and both my '06's are still original.

I see nothing at all in the 2010 to make me think it would not hold up at least as well. To the contrary, with the cylinder being offset, skirt thrust is reduced, and the piston should wear even less than it has on older models.

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Gray, Do you think the crank is going to wear faster? looking at the angle of the rod in relation to the combustion process, it seems that the downward force on the outside perimeter of the crank would make the main bearings and crank wear faster.

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The offset gives a higher angle on the compression stroke which has considerably less force on the rod than the power stroke, where the rod angle is now less. Should improve skirt wear.

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The RM-Z450 manual says 15 hours also, but they've been known to last over 100 hours of hard riding. Don't worry about that.

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15 hours is what the manual has said for years, and for at least that long, it's been a ridiculously low number compared with reality. The real answer depends on exactly how the individual bike is used. A top pro racer is going to get considerably less time out of his engine in general than a purely recreational rider, an occasional racer, or even a fast amateur.

YZ450 pistons have mostly been good for at least a season except perhaps for the very serious racer. I ran my '03 on it's original piston until I sold it at the end of '07, and both my '06's are still original.

I see nothing at all in the 2010 to make me think it would not hold up at least as well. To the contrary, with the cylinder being offset, skirt thrust is reduced, and the piston should wear even less than it has on older models.

agree I never had any issues on 400s,426s or 450 yamis

but they were all 5 valve motors - this is a totally new design and the verdict is not out yet on reliability of parts in the motor...historically Yami are the most dependable...hopeful that the trend will continue

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but they were all 5 valve motors - this is a totally new design

The design of the head has no bearing on the life of the piston, and the '06 was a "totally new design", too. The design elements that have changed that do bear on the piston have changed in ways that should contribute to longer, not shorter piston life, as has already been said. As far as 4 valve vs. 5, we've been over that, too. The number of valves has no bearing on the reliability of the assembly.

http://www.thumpertalk.com/forum/showthread.php?p=8599857#post8599857

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The design of the head has no bearing on the life of the piston, and the '06 was a "totally new design", too. The design elements that have changed that do bear on the piston have changed in ways that should contribute to longer, not shorter piston life, as has already been said. As far as 4 valve vs. 5, we've been over that, too. The number of valves has no bearing on the reliability of the assembly.

http://www.thumpertalk.com/forum/showthread.php?p=8599857#post8599857

I agree GreyRacer the head has little bearing on piston life....but you have to agree this motor is a completely new design...this is really my point. I am confident it will be as bullet proof as it's predacessors.....where is that darn Yami Rep :moon:

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The RM-Z450 manual says 15 hours also, but they've been known to last over 100 hours of hard riding. Don't worry about that.

I've had 50 hours and going strong.

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