Valve job do's and don't

[snyderman]

Generally, the head is left alone until it NEEDS the work, because of the tight tolerances with valve clearance. Feel free to replace the seals and clean up the seats and valve faces, but when you start cutting the seats or dressing the valve face, you might also have to trim some off the small end of the valve, so you can still use standard-size shims.

As you cut away on the valves or seats, the valve will recede farther into the head. This will require the use of thinner shims. After a few thousand miles of use, most of our bikes are already using shims that are about half a milimeter from the smallest shim, so use that as your guide.

Oh, and our valve clearances only get tighter, so make sure you trim enough off the end of the valve to get you to where you need the thicker shims at first.
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I had a valve job done on my head. 2 of the valves were burnt so bad that they had to be replaced. I brought it to a recommended shop and they ground the valves and seats and reassembled the whole works. The assembled head is still on my bench. This is the first I have heard about needing to trim the valves after grinding. Is there any way I can measure to know how much to remove? I really want to get it right the first time I torque the head. I am guessing that I will want a machine shop to trim the valves.

[Willmrx]

I am using all OEM Suzuki parts! I thank you all for you help!

Will

[Steve]

I had a valve job done on my head. 2 of the valves were burnt so bad that they had to be replaced. I brought it to a recommended shop and they ground the valves and seats and reassembled the whole works. The assembled head is still on my bench. This is the first I have heard about needing to trim the valves after grinding. Is there any way I can measure to know how much to remove? I really want to get it right the first time I torque the head. I am guessing that I will want a machine shop to trim the valves.

My suggestion would be to install the buckets and shims for one cam while the head is still on the bench. Use your thinnest shims, see if there is any clearance at all. If not, order a shim (or two or more) that is several sizes smaller than your thinnest shim and try that to see if there is any clearance. Once you are able to measure clearance, you can compare that with the shim that is installed to see what shim you will need. You will need to repeat that for every valve, so be sure to take good notes.

Need a good note-taking tool? Look in my sig. It will also help you determine what shims you need, then keep track of your adjustments later on.

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