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Valve question...

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Good morning family. I'm trying to get an understanding of how my motor actually Works. So heres my question. When its time to replace the valves in your bike and the seats have to be cut, I would assume that would lessen the length between the seat and the can lobe to some degree. To compensate for this shorter distance, can smaller shims be used to achieve proper clearance? Or is this something that had to be taken into consideration when ordering new valves? Meaning, do valves come in different lengths or is there a standard length? Any insight is greatly appreciated. Thanks fellas!

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You compensate by using smaller shims. If so much is cut off the seats (insert billy bob the machinest) that you can't find a small enough shim, then your looking at new seats being installed.

Only let professional motor builders cut your valve seats.

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Well, everything is replaceable. If new valves are required, the seats need to be cut before new valves are installed. You can get about two valve replacements out of the stock seats before too much material is gone and they need to be machined out and new ones installed.

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Gotcha.so just the seats are a replaceable part? Their not carved out in the head?

If the seats aren't damaged, or haven't been assulted by a ham-fisted machinist, they should last for many set's of valves with only a very light clean-up cut (.001-.002" at most).

The only other time seats would need replaced would be for the instalation of oversize valves or the need to use a different type seat material, like beryllium-copper.

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I can only speak for my self, I ride offroad and am never on the redline. I change my valves when the seat has shifted .012, some may say that is too long but I have had no issues with that polocy, and again I am not a motocrosser. Also the center intake shifts the most so you will be changing the other intakes with less wear,

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