Mike,

Curious about the muffler or pipe you will use. Do you know if it was a muffler for the YS 4 strokes or is it an actual tuned pipe? If it is a muffler, I don't think you will get much boost.

The 18.1x10 apc is no real load for this engine. It's good enough to try a flight or two and it will not cause any damage or anything like that. But to get into the engine's power band, I suggest more load.

Interestingly, running a lower load doesn't mean gobs of rpm. You will get a false indication. I've tried it before so I know how it behaves.

Mike I've used from 1800 to 2200 ma batteries with the IBEC driving the CDI, and get 75 minutes comfortable flying time. A 2600 ma will buy you more flight time.

Love to hear how your early flights go. If it's like my first few, the smile was ear to ear