06 YZ450 engine noise

Got a couple of new YZ450s that seem to make a lot more engine noise than in 05 and 04. This noise showed up after the break in period. Kind of a clunking noise in the motor.

I know the motors are almost mechanicly identical and the earlier units have proven bullit proof.

Someone said maybe the aluminum frame may transfer noise better?

Or possibly the bigger cases to hold all the oil instead of the frame?

The oil changes didnt show any thing out of the ordindary.

Any ideas?




Yeah, I'm sure your fine. But......! You should be punished for having more than one! All of these poor guys out there waiting on their one! :applause:

If you have 2 and they both sound the same (noisy) then the odds are that it is perfectly normal. If one sounds significantly different then the other then I might be concerned.

My 06 YZ250F had something very similar happen to it. After the break in and changed some jetting, the motor made, what seemed to be an internal motor sound, a loud clanking / clunking noise as I tried to start it. It finally started after a couple of tries and once it started and reved it once the noise disappeared and never came back. I got real worried / paranoid so I talked to a service mechanic at a Yamaha dealer. I described my problem and he said it sounded like the slide in the carb was clanking around, he said it is real loud, and sounds like the motor is going to blow up or like you just busted a valve. The noise has not returned. I don't know if this is the same problem / noise but I hoped this might have helped.

do you still have your stock chain???? my chain streched about 3 inchs on first ride, at least it felt that way, anyway, I have chain scratchs on my swingarm now after my first ride. Theres a new chain on her now.........

The stock chains are junk, I remove them before its ridden and put them back on when I sell them. "Look its got a brand new chain"

I run Regina O ring chains.


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