Should I replace my piston?

I have an 09 450 with 50 hours of vet. int. racing.

My valve clearances are within spec.

Do I need to remove the cylinder and check or replace the piston?

I replaced the piston/rings in my 2008 at 128 hours of B class riding/racing. The piston still looked fine and I would have felt confortable running it another 75-100 hours before checking it again. Yamaha's are notorious for there durability, and I've seem/heard of stock engines running perfectly with well over 200 hours.

I'd say no, not at 50 hours. I'll put 100 hours on mine before I replace it, I run MX only and race B or intermediate. I did however, replace my cam chain at 60 hours as I've read about a number of failures assoc. with them. I had 6 or 7 links on my cam chain that were binding (only noticed after removal). For less than $20 I'll replace it in another 40 to 60 hours which will more than likely be when I replace the piston.

353 hrs on an 09 450 without opening the engine for even a valve check. These Yamaha's are amazing. High quality true synthetic oil and maxima fft air filter oil really pays off.

I'd say no, not at 50 hours. I'll put 100 hours on mine before I replace it, I run MX only and race B or intermediate. I did however, replace my cam chain at 60 hours as I've read about a number of failures assoc. with them. I had 6 or 7 links on my cam chain that were binding (only noticed after removal). For less than $20 I'll replace it in another 40 to 60 hours which will more than likely be when I replace the piston.

What oil are you using?

So long as the oil has been changed + air filter kept clean you're good to go...and go.....and go

353 hrs on an 09 450 without opening the engine for even a valve check. These Yamaha's are amazing. High quality true synthetic oil and maxima fft air filter oil really pays off.

I wish I could put that many hours on my bikes. I am lucky if I can get 100/yr. I am only at about 35 this year due to injury/illness.:thumbsup:

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