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need some help with predator 212 carb

B

bunk

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I've got a new predator 212 and I put a header and muffler on it removed governor but left stick air filter in place due to rules..I bought an arc jet kit that comes with a .036 and .037 can someone tell me which one would be best for dirt oval tracks...I don't know which would produce more power or less power or what?
 
have to agree...like screamer said...pick one and hope it was the right one! i would look at the plug after you've changed the jet and put a few full throttle laps down. that will help tell you if your running rich or lean...
 
With stock airbox try .035-.036". It will only want that .037-.038" jet if you've got a filter/adapter on there.
 
Thanx for the info ..I put the .037 in it and it kinda spit and sputters a little bit at full throttle I'm gonna try the .036 like u said rkcarguy...I'm new to this but you guys on here have been a great help
I've built this kart from frame up by myself its an old phantom gauntlet but man it runs great and drives great ..no track yet but well soon see
 
With the stock airbox, you will be really lucky if you even get a .035 jet to work, the biggest jet iv ever been able to use with a stock airbox was a .032, along with a .022 low speed jet. I cannot see the .036 working, maybe it will if you have the stock low speed jet in it. Alot of people dont realize, most predators come with a .575 bore carb, compared to the .615 bore clone carbs, so the carb is really gonna limit the power you get with the predator engine, and is gonna limit the amount of air you can get to the engine also. You need to upgrade the carb if yours has the .575 bore carb, check it and see.
 
But the difference in area between a .032" jet and a .036" jet is 26.6%. I would be afraid to make such a big jump in jetting. I suggest making .001" changes.
 
In my opinion you may get along with a 36 Jet with the stock filter during colder weather....however a 36 Jet will be quite a bit too much during warmer weather with a stock filter. With a K&N type filter on a Predator the 37 works good in cold and 36 when its hot, but since you are confined to using the stock filter I would also suggest a 32 Jet .
 
alvin l nunley said:
But the difference in area between a .032" jet and a .036" jet is 26.6%. I would be afraid to make such a big jump in jetting. I suggest making .001" changes.
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Al, sometimes you have to ignore the numbers and difference in jet size percentages and just tune the engine by what works rather than what the math says should work. Not trying to be rude, but those of us offering advice on this have done it enough that we know what works and what does not work. I was not the one who suggested the man to try a .037 jet in a carb when the engine came stock with a .028, i knew it would not work when he is using the stock airbox. Even in cold weather the biggest jet i ever had work with the stock airbox has been a .032, .030 would actually be closer to the right size. These stock airboxes just do not have enough air coming into them for you to be able to use anything bigger than a .032. While it may run on a big jet, it will run better and make better power on a smaller one. I can get my AKRA clone to run good with a .024 low speed and .040 main jet, but that same engine makes better power with a .038 main and .026 low speed jet. Why? I do not know, but i know what works.
 
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