[TR] Valve Clearance

Greg Lemon glemon at neb.rr.com
Mon Mar 19 20:12:46 MDT 2012


I have notice on another thread discussion of valve lash if you have a 
non-stock cam how the cam grind can affect valve adjustment.

So here is my question.  I have a TR250 with a very mild cam grind.

The grind is very similar in specs to the TR5 cam, though not identical, 
lift and duration are very close.

The cam grinder's lash spec is .014" stock is .010".  However, the cam grind 
data is from a "British Performance" generic cam grind sheet, not 
specifcally for
a TR250/6 motor.

I did some research and the spec for the TR5 grind is if anything slightly 
more agressive than what I have (very slightly), and the valve lash for a 
TR5 is the
same as stock TR250, .010".

I have it set to .010" and all seems fine, idles good, accelerates smoothly 
and strong, etc.

Any thoughts, .010"?, .014"?, split the difference .012"?

Greg Lemon
68 TR250 


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