carb jets on green plate

I’d say he means the manufacturer and how well your particular carb flows... those are mass produced from two different companies so you are guaranteed to have good, bad and average carbs
 
You didn't mention where you're located at, it's important. Although the recommended sizes seem reasonable and close, how would you know without the posters barometric pressure and temperature? The other poster might be at sealevel, and hot. You might be at a different altitude, and cold. An Air density reading is how you tell the difference. A 1% change in air density calls for a 1% change in jetting. With the jet recommended, a .039", if the air density changes 1%, you have to change the whole size 1%. In this case 1% change in air density calls for a .0002" change in hole size. That's right at 1%. Some of this information was taken off the Longacre website.
It's called tuning, and tuning is tough. (Al Nunley)
 
You didn't mention where you're located at, it's important. Although the recommended sizes seem reasonable and close, how would you know without the posters barometric pressure and temperature? The other poster might be at sealevel, and hot. You might be at a different altitude, and cold. An Air density reading is how you tell the difference. A 1% change in air density calls for a 1% change in jetting. With the jet recommended, a .039", if the air density changes 1%, you have to change the whole size 1%. In this case 1% change in air density calls for a .0002" change in hole size. That's right at 1%. Some of this information was taken off the Longacre website.
It's called tuning, and tuning is tough. (Al Nunley)

Al,

The exact wording of the response was ".038 main .026 pilot will get you close depending on casting". Do you see that part "get you close"? Id say he can figure it out from there. You're consistently trying to make things more complicated.

As for my advice. Once I find a decent jetting that works in what would be 75% of your races, I leave it alone unless something extreme happens with the weather. I actually only change jets in the early or late season. Everything else is ran on what I find to be the best for those 75% days.
 
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