Predator 212 main jet sizes

Kartracer93

New member
Track rules allow for the governor to be removed, 10.8 pound valve springs and the low oil sensor to be removed. but yet they allow a main jet change, is there any need to change the main jet from factory to a bigger size without changing the stock air box and muffler? cant be no bigger than .35
 
Track rules allow for the governor to be removed, 10.8 pound valve springs and the low oil sensor to be removed. but yet they allow a main jet change, is there any need to change the main jet from factory to a bigger size without changing the stock air box and muffler? cant be no bigger than .35
Hard to say for sure, but nothing wrong with experimenting. I know for a fact that air density has something to do with it. High air density needs more fuel in the engine. Longacre says a 1% change in air density calls for a 1% change in fuel flow. With a .035" jet, there's a given supply of fuel. With a 5 point changing in air density, you would need to change the jet by approximately .001". Trust me, that's significant!! That would be a 5% change in fuel flow. Here in Austin Texas, over a years period of time, I've recorded air density changes of 13 points. I've seen changes of over five points in one day. I've recorded data daily for a 2 1/2 year period. I'm retired, I have time on my hands. lol
 
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