Which valve shim to use....

[cerealkiller]

I'm in the middle of a valve adjustment, and I'm wondering about which shim to use when I seem to be in between sizes. I think being on the tight side of "in-spec" is better than loose, but maybe I'm over thinking it.

The valve in question had .087mm clearance (should be .1-.15) and a 182 shim under the bucket (I presume from the factory). The manual says to round the 182 to 180 and then use the chart to find the recommended replacement. It suggests 175.

But when I do the math, this would put me at .157... .007 over spec. Whereas if I used a 180, that should put me at .107. - just barely within the standard clearance.

So should I:
1. Listen to the manual and go slightly looser than the recommended clearance.
2. Use the 180 to stay within the recommended range.
3. Find something else to worry about since we're talking about 100ths of millimetres.

[primerib72]

I always went on the looser side of the range on my old yz450.

[twotired]

Being on the tight side is not good when it comes to valve clearance. The clearance goes down with wear that's why your valves were tight when you checked them. I'd go for the .157 if it was me.

[350scott]

As the others said, go slightly loose.

[cerealkiller]

Thanks. I'm putting it together now.

[axel99]

X2 on the loose side