Grinding valve shims

[Guest]

I took my 1000G to Trevor Hedge Racing today, for them to balance the carbs etc, plus check and adjust valve clearances. Gavin (Trevor's son, who deals with the multi-cylinder Jap stuff) says he'd be inclined to adjust shim thicknesses using their surface grinder, rather than buy replacement shims. Sounds ok to me, but my only reservation is the thickness of the hardening (or are they hardened all the way through?).

Anyone happen to know how much it's safe to grind off the shims?

[60ratrod]

I would just have them swap the shims. Grinding shims isn't new, but unless you are trying to set this bike up for racing where EXACT tolerances can determine lap times, i would just have the shims swapped to within suzuki's spec'd range

[Jon]

I'm definitely not going racing - just thinking that the grinding option would save some money. New shims are about £10 each and there are 8 valves, and the previous owner told me he'd never checked the clearances. I'm expecting most/all clearances to be too small when checked. Good to learn that grinding shims is acceptable practice, thanks for that info.

[GregT]

Yes, hardened all the way through. Only ever grind one side - and that side goes down into the bucket so the cam bears on an original face.

Given how hard it is to find those shims now, grinding has probably become more common.

[Chris G]

I'm definitely not going racing - just thinking that the grinding option would save some money. New shims are about £10 each and there are 8 valves, and the previous owner told me he'd never checked the clearances. I'm expecting most/all clearances to be too small when checked. Good to learn that grinding shims is acceptable practice, thanks for that info.

Has your guy measured the clearances, you may save a few quid by simply swapping some around, I managed to swap a few around when I did mine, just looked at my invoice for the shims from a main stealer in Keighley £8.70 each.

[hampshirehog]

My local dealer gave me a bunch for free. The storeman said they were just cluttering up one of his shelves and he didn't even know what they were for.

[Jon]

Free shims would be ideal! Failing such good luck, as said below, with any luck at least some can be swapped around, and the rest ground (as said below, ground face to go downward). What's the name of the spares outlet in Keighley?

[Chris G]

Free shims would be ideal! Failing such good luck, as said below, with any luck at least some can be swapped around, and the rest ground (as said below, ground face to go downward). What's the name of the spares outlet in Keighley?

Colin Appleyardrs if your spending a few quid ask for some discount, I always do, after you get them measured ask on here if any of us in the UK have what you need.

[ukjules]

Just so you know a while ago on my current bike I ground down a stock shim to 1.9mm.
Way out of spec BUT I have had no issues whatsoever and HAD to do it.

I did this as I foolishly did not bench test the valve clearances so
I could grind a valve end. That is what you should do always.

I have been castigated (rightly) for doing this but it is working fine still and zero issues.
I dont advise it but it is worth knowing if you foind your self in a "desert" situation.
The second i have any issues i will inform of course but 1500 miles and not a squeek.