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Valve Problems

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I just spent some time looking through all of the other bike forums. Guess what...the only bikes that don't have valve recession issues are the Yamaha's. Both Honda's, the Kawasuki, Husky and even KTM all have intake valves that tighten. I've owned 2 CRF 450's and I haven't had any issues, and I don't know anybody that has, but clearly it happens to a few. It seems to happen a lot more to the 250f's.

So why do the Yamaha's have fewer problems? If it happens across so many brands it isn't a design or manufacturing defect. I doubt it's dirt ingestion either. Why does it happen to some, but not most? Seems like valve float, weak valve springs or something like that, but what do I know. I do know I shortshift and rarely hit the rev limiter, does riding style play a role?

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I would say its the 5 valve set up.

DING DING DING! We have a winner folks!

The 5 valve design can flow just as much with less lift and milder cams, less wear and tear on the vale train overall. But EXPENSIVE to repair if you break something...

Each design has it's merits...and flaws.

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At least you can make it home on a yamaha .... :cry:

Oh yeah, and it turns too! Stock. What's that? It also has more power? You're right the yamaha is junk :cry:

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Why wouldn't dirt in the intake cause problems? After all dirt=sand=the stuff used to make sandpaper. What is confusing for me is why people think that only one thing can cause problems. I say dirt in the works is bad. I also say sacking the valve springs and revving till the valves float is bad. Hmmm, 2 bad things, well I never....

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