I have a couple questions on the proper way to tune a Raptor on a dyno.

1) Do you change jets and needles based on air/fuel ratio at "throttle position" or "RPMs"?

2) Does needle position affect 1/2 throttle fuel delivery or mid-RPM fuel delivery, or both.

3) After you get a flat A/F curve at full throttle, do you check 1/2 throttle on the dyno, and how?

My main question is, if my full throttle dyno run gives a rich A/F in the midrange (4000-7000rpm), and lean A/F at high rpm (8000-9000), what do I change? Do I drop the needle to lean out the mids, and increase the main jets to richen up the top?

One last Q? What would increasing only the right main jet one size do to my A/F curve? Thanks for any info you can provide!

RR1

 

Thanks Airraptor! I do remove the front plastic and rubber stuff, and set the gas tank on. I am buying a second set of stock carbs so that I can change jetting on one while the runs are being done with the other.

As you can see, I am running MUCH larger jets than anyone else with stock engine internals that I've talked to in here. I just want to make sure that I make the most of my tuning time next visit to the dyno.
It looks like I am going to be around 195/205, needle on 2nd clip from the top. Has anyone heard of this setup?

RR1