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CRF450R Valve shim calculator

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I am helping a buddy of mine with his valves tomorrow on a 2009 CRF450 and need some shim advice.  A guy posted over on the YZ forum a valve shim calculator.  Fantastic tool and I downloaded it for my YZ.  I searched for the same for the CRF and found a 11 year old tread with something similar but the spreadsheet wouldn't pull up from the link.  I'm guessing because it's so old?  It was started by a guy named Lackey-92.  I'm wondering if I can use the YZ calculator and just plug in the Honda's numbers?  Any help is appreciated.

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Quick calculator, all you need to have is a dial caliper and some feeler gauges.


Measure your clearance


Disassemble and pull out shims.


Measure thickness of installed shim( I like to use thousandths)


Find shim that is smaller by as many thousandths difference as needed to make clearance .006 again. 




Example  clearance at .002   shim size .075.  You need a shim as close to .071  (.004 smaller to make a gap of .006)as you can find.  (remember +/- .001is ok)


Getting out the calculator is a waste of time, and can add confusion for some.

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Shimming is a very simple process.. don't over complicate it.


Measure the clearance, write it down, pull the current shim out, measure thickness, write it down, do the math, install new shim that will put you in the desired clearance range.


You shouldn't have any problems. 




Make sure you have all the necessary tools to complete the job before you start. Use a torque wrench on the cam tower/bridge bolts to get consistent and accurate clearance readings. 


Good luck.

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