Thanks for the info about this engine....

I've advanced, and then retarded the timing from the ideal settings, and then set the timing to achieve peak RPM. Then I peaked the RPM by adjusting the "high" needle valve, and the performance I get is...... 5880 rpm from a 20X10 JXF propellor, and only 6460 rpm form an 18X10 Classic Master Airscrew!

That seems to be a disappointing.

What type of performance figures should I be getting?

Cheers,

Marcus.