Shim Sizing?

[snydes]

So I need to get new shims for my valves as now rechecking since last valve job they are on the high end. Now I would rather not buy a Hot Cam Shims kit because they only have 3 for each size(stupid idea) and on my original shims, to size them down originally i set up a tool and grinded them down(they are flat, no roundness) and since i grinded them I dont have the numbers on them anymore. My question is, the numbers on the shims the go up or down by 5(or .05 i cant tell/remember) what does that actually mean? I need to be able to reference my shim measurement with a caliper compared to a new shim with a number. Is the number an actual size or reference size? is there some sort of chart to tell? If i have to i will buy OEM or shims for some other bike that also takes 7.48mm shims but id like to know the sizing.

[Evilchicken0]

I think the height is the size in mm where 200 = 2mm (but get hold of one and test this) these shims are common to a lot of makes not just Yamaha so you can ebay search vale shims and then see what's around.
As long as the gap is within tolerance I wouldn't worry to much.

[TomcatMJ]

Get a micrometergauge and check a shim with number on, numbered with 175 should be 1,75 mm thickness ( so it will be actual/absolute size,not a reference/related size to something else) and then your own grinded ones to get their thickness as well, write down the measurement and mark the shim somehow with a permanentmarker after measuring to avoid mxing up undefined/unkown sizes of others without numbers

[Asudef]

I just did this as well and know they go up or down 5 ie. 165, 170, 175 which is equivalent to 1.65mm, 170mm...

My stock shims were actually in increments of .25 rounded, so 160, 162, 165, 168 which is sort of weird.


Hot Cams only go in increments of 5 but I found Pro-X shims from here come in .025 increments. I read Honda shims are also in .025 but I couldn't find any nor the Yamaha ones like mine.

Only problem is they aren't printed but lightly etched, with moly grease on them, it gets really hard to read.

[Evilchicken0]

You only need to read them once - then make a note of their position relative to the valve. Put them with the number upwards so it doesn't get rubbed by the valve.
To be honest as long as they're in spec they'll be fine, I'd only replace if they're out of spec or right on the line and I wouldn't worry if they go up by 5 or 25 you're talking about a 1/4 of a mm

[Asudef]

True, I just wanted them all to be about the same like the EXH were and they cost the same. Bike starts great but runs like an absolute dog for a host of other reasons though.

[Evilchicken0]

Once they're in tolerance balance the carbs

[Asudef]

I have them bench sync'd, will do the fuel level line next after setting/checking the pilot screw.

[Evilchicken0]

You need to balance them to the cylinder they serve, these engines will rough if the carbs are too far out