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Valve guides

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Hey guys, Finally stripped the head off my bike to change all the valves,springs,guides etc Im going to send the head away to get the seats cut and fit the rest myself. Ive managed to get the valves out but not sure how to get the guides out, can anyone advise me on the best way to remove them.

Thanks :bonk:

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Generally, you heat the head to 300 degrees F and knock them out with a piloted punch.

Installation goes the same way and it helps if you chill the guides in acetone/dry-ice before installing.

If you didn't already know, you will have to ream or hone the guides to the finish size after they are installed.

Are your old guides worn past their service limit?

You didn't mention what type machine you are working on.

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Generally, you heat the head to 300 degrees F and knock them out with a piloted punch.

Installation goes the same way and it helps if you chill the guides in acetone/dry-ice before installing.

If you didn't already know, you will have to ream or hone the guides to the finish size after they are installed.

Are your old guides worn past their service limit?

You didn't mention what type machine you are working on.

Its a 09 kx250f, I was just going to change the guides for peace of mind but looking up on it and it seems a pig of a job to do. What's the easiest way to check them to see if I can get away without replacing them?

Thanks

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Let the folks doing the seat work check the guides and replace as necessary...they usually have the tools to do it.

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Its a 09 kx250f, I was just going to change the guides for peace of mind but looking up on it and it seems a pig of a job to do. What's the easiest way to check them to see if I can get away without replacing them?

Thanks

The preferred method is with a dial-bore gauge, like Mahr small bore gauge.

Usually, guides are good for 2-3 sets of valves but that really depends on how the machine is used (assuming you are servicing the top end every 20-40 hours)

If it's a dedicated race machine they should be replaced every time the top end is serviced.

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