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420 Predator jetting question..

Evolution Clone

Evolution Clone

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Putting a 420 in a golf cart burning mid grade gas,have to run the kart type airfilter and robertson pipe for cart and a stock rvl muffler ..what size should my jets be..thanks in advance...
 
Are you planning lots of high rpm running ?
You running the governor ?
Whats the intended use golf , round the neighborhood or crusin the beach .
 
I wouldn't go crazy on the sizes .
No idea whats in it but a .020 and .034 .
A couple thousandths bigger on each to start is my guess .
Shoot it may work fine with stock .
If it don't get too hot .
 
Have you done anything to increase the compression ratio? If not, there's no need for the midgrade fuel, it might even run better on the regular. Octane is not a measure of a fuels performance potential. It's a measure of the fuels resistance to detonation, with a stock ratio, there's no need.
Aftermarket air cleaner let's more air in, aftermarket exhaust pipe let's more air out. That means you need more fuel. I would start rich rather than lean. It's possible to hurt the engine if it's lean, if it's rich, you're just gonna go slower. Thing about that is, it's real easy to go leaner. You want to change the low-speed jet along with the high-speed jet. Their balanced now, you want to keep it that way.
Are you going to run it with a clutch? What kind? That motor probably reaches peak torque at a low RPM, don't spin your clutch at too high of an RPM.
 
alvin l nunley said:
Have you done anything to increase the compression ratio? If not, there's no need for the midgrade fuel, it might even run better on the regular. Octane is not a measure of a fuels performance potential. It's a measure of the fuels resistance to detonation, with a stock ratio, there's no need.
Aftermarket air cleaner let's more air in, aftermarket exhaust pipe let's more air out. That means you need more fuel. I would start rich rather than lean. It's possible to hurt the engine if it's lean, if it's rich, you're just gonna go slower. Thing about that is, it's real easy to go leaner. You want to change the low-speed jet along with the high-speed jet. Their balanced now, you want to keep it that way.
Are you going to run it with a clutch? What kind? That motor probably reaches peak torque at a low RPM, don't spin your clutch at too high of an RPM.
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It's a golf cart stock everything ..I'm a small engine tech all I want to know is what size to drill jets for the changes...I can guess..thanks
 
Wow if you run the aftermarket filter you got to jet it... where's the engine builders on here...I know I've been gone a few years but basics are basics....
 
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