ageedog

Any help or feedback on this subject would be helpful.I am running 30% in a Novarossi N21B 2001 BF
motor do I need to shim the head? The factory spects say "not sugested over 25%" Any sugestions on how much to shim? I have looked for the factory sugestion but can't find anywhere.Does Anyone have exsperiance running this motor on 30%?or the proper way to determine shime thickness.

Please help,

Darrin

hrdcoreglf

If you are getting the performance you desire as it is now there is no reason to shim it.

Colt4g63

I'm going to 2nd leaving the shimming stock for 30% on that mill.

RBMike

You could run 25% or you could add one 0.1mm shim. Unless you live at altitude. If you live above 3000 or 4000 feet above see level, you won't need a shim to run 30%.

ageedog

The performance is great for me! I didnt know if running it like it is will shorten the life of the motor. I am a firm beleiver in if it aint broke dont mess with it. Excluding rutine maintenance .I will ask around the track and see what they have to say also.
thanks,

Darrin