First of all i want to introduce myself.
My name is José, I´m from Chile and i´m an industrial engineer.
I ride motorcycles since i was 8 years old. Now i´m 25 years old. I race motocross and enduro in the chilean nationals, and also i´ve been racing/riding in the US numerous times, especially in Socal, Florida and Nort/South Carolina.
I ride a 2009 CRF 250r, engine completely stock, but some days ago i had to replace the intake valves so i did a valve job. I cutted the seats and put OEM valves on it.
My question is:
I know the intake valve clearance recomended by Honda is 0.005 +-0.001 but i´ve heard that is better to leave the valves in a tighter especificaton in order to extend it´s life.
In other forum a guy said that he recomends leaving the stock valves at 0.0035-0,004 because this will increase the valves life due to the valve closing speed against the seat will be reduced.
I know it sound logical, but someone have ever heared or tried this?
p.s. The guy who said this is a NASCAR engine mechanic,
P.S.2 Sorry for my english, it´s not my mother lenguage