Test runing sporster .21 from ebay,little used,but piston looks like new.
10% nitro
20%castor
Weather -2.5°c
Master scimitar 9x5 13000rpm
Apc 9x4 13800rpm
Idon't have any really good normal .21 engine ,so ido not know whether
These good readins?
My .21k&b rear exhaust,mvvs and rossi rews over 20krpm 7"prop.