CRF's Only Forums

I get asked frequently about valve shimming and the use of feeler gauges. First, I don't use a standard feeler gauge. This is what I use:

http://www.crfsonly.com/catalog/product ... ts_id/5034



These are individual gauges designed specifically to measure valve lash. This speeds up the process significantly. I pull the exact size for the correct gauges for each valve clearance specification (see below for clearance specs) for an initial measurement. Based on the results I pull the gauge that should fit the actual clearance. Once I have a clearance measurement I measure the shim with a digital caliper and use the CRF's Only shim calculator to do the math.

Shim calculators can be found here:
http://crfsonly.com/howto/index.php

The thing to keep in mind is the clearances have a plus or minus 0.001" range. These gauges are in increments of 0.001" so it's perfect for quick measurements. Because they are not very wide they are easily place under the rocker arm or slid between the shim bucket. It is also easier to "feel" the resistance because you are only dealing with the one gauge not a large number of gauges above the one you are using. As is often the case the right tools make all the difference.

Valve clearance specifications:

CRF450R
In -> 0.16 +/- 0.03mm (0.006 +/- 0.001 in.)
Ex -> 0.28 +/- 0.03mm (0.011 +/- 0.001 in.)

CRF250R/X
In -> 0.12 +/- 0.03mm (0.005 +/- 0.001 in.)
Ex -> 0.28 +/- 0.03mm (0.011 +/- 0.001 in.)

CRF150R
In -> 0.16 +/- 0.03mm (0.006 +/- 0.001 in.)
Ex -> 0.26 +/- 0.03mm (0.010 +/- 0.001 in.)

have a 2013 crf 150r does it use the same size shims as whats in my 2005 450r or are they smaller? i have a hot cams shim kit for my 450 but wasnt sure if i am going to have to get another kit for the 150.

shim sizes:

150R 7.48mm OD shims
250R 7.48mm OD shims
450R 9.48mm OD shims

Excellent tools for the job. Must haves...