Wondering what you guys with mods are running for a main jet. I pulled my plugs last night and they were pretty dark. I'm running a 165 main right now do I go back to the 160 or will adjusting my air fuel mix screw lean it up a bit. I dont want to go to lean and fry the motor but you can tell its a little rich. Thanks

There are several circuits to tune in the carb and your main only affects the top 1/4. The PILOT AIR adjustment screw affects the bottom 1/4. Read the tuning manual, you are talking about two different things as far as adjustments. If you want to adjust your main by reading your plugs there is a procedure for that.

I thought that the air fuel screw helped through alomost all the throttle range except right on top end. I did do the test with the plugs. I ran it wide open for maybe a couple hundred yards and then shut it off and pulled the plugs still dark. Is the 160 to small, am I better to just run it a little rich???

I think to do the plug test you wanna put new plugs in and run it wide open for 10 minutes or so, then shut it down without idling and check em. Someone will correct me if I'm wrong but I'm pretty sure you need a new set of plugs, and need to run more than a couple hundred yards.

ok thanks

and look for this:

Matt.....i got your message....lost your number though. Put a 160 in it......you'll be fine!