Originally Posted by
British Menace
Hi
I have a 5 port .21 GO with a standard head and I'm running 15% Nitro in her.
Does this motor come shimmed for 15 - 20% Nitro or 30% ?
Sorry if this Q has been asked a dozen times before....

just no time to go looking. Sorry.
British Menace
They come shimmed for 30% out of the box. You will be much better off changing from the 15%. Run 25% and you will notice a big improvement in all around performance. These motors love a good dose of nitro