tuning questions

[elwilliams13]

2006 .20 over, recreational port, coolhead 19cc dome @ sea level compression 185 per cylinder. The guy that did my porting told me to run +7 timing and also said that this would work on AvGas. Right now I have AvGas in the tank and using BeNol at 40:1 timing set to +4, When I accelerate it runs good but when I let of the throttle and keep it there it begins to surge and cut out, once I gas it again or shift to a higher gear it goes away. I have boyesen rad valves, stock carbs,toomey t-5, 340 main, 32.5 pilot, 1.0 turns out, needle in middle clip. Is this jetting related or do I need higher octane gas. I have 21cc domes I can put on that puts me at about 160psi. I mostly ride long trails where I can run wide open 50% of the time. What do you think? suggestions.

Edited March 9, 2008 by elwilliams13

[slowblueshee2]

2006 .20 over, recreational port, coolhead 19cc dome @ sea level compression 185 per cylinder. The guy that did my porting told me to run +7 timing and also said that this would work on AvGas. Right now I have AvGas in the tank and using BeNol at 40:1 timing set to +4, When I accelerate it runs good but when I let of the throttle and keep it there it begins to surge and cut out, once I gas it again or shift to a higher gear it goes away. I have boyesen rad valves, stock carbs,toomey t-5, 340 main, 32.5 pilot, 1.0 turns out, needle in middle clip. Is this jetting related or do I need higher octane gas. I have 21cc domes I can put on that puts me at about 160psi. I mostly ride long trails where I can run wide open 50% of the time. What do you think? suggestions.

I would guess you have to big of a pilot. I would also experiment with less timing. In my experience too much timing would make the power really on off.

[elwilliams13]

I was sort of thinking that after a few more rides. What about the fuel octane, so far all the guys told me has been OK just don't want to thrash this motor.