Originally Posted by
gansei
inner head and piston head got pockmarked.
maybe plug die cause pockmarked.
you must shining pockmarked inner head for good idling.
The OS comes with 2 x shims
i have ran for a few months with both inside, instruction book says 2 shims for 30% nitro
1 shim = 16% nitro
maybe my fuel mix is bad - 10% synthetic 5% castor run AT Red Nitro Fuel 16% content
plug either Nosram 6 or 7