Help with G2 jet install

[sho305]

Someone has to make the cam, they reweld one and regrind it different than stock. You could try to port the head the ports are tiny, however you will cut through and have to weld that if you do much. I don't know who makes cams likely precision cams might or someone like that, maybe plowmans knows. It used to be expensive to get one made but I don't know really. A larger carb and header you would get more from it for sure. The problem is you can drop a clone in there for 250 plus a clutch or adapter, and you can get lots of performance parts for it. Even stock it has significantly more power it spins 22s up hills and stock engine has no chance of that. If you get a flywheel and rod and cam you can get an easy 20hp out of them and up to 30 if you go nuts. But by then you may have as much into it as a v twin lol. Go to NR racing and AGK they both have performance kits for clone gx390. To run high rpm you need a flywheel they come apart over 6K, and to run a cam you need a better rod also. You can mess with the stock engine just saying the only way anyone has really helped one is by making a cam, there are posts here about it someplace. I think they also raised the compression.

I hogged the jet with a torch tip cleaner, I filed it larger and larger until it ran right.

[DOOmsman]

I tow and play up in the mountains and I'm going to hog out my jet soon. You may not see any improvement at altitude with a larger jet?

[sho305]

Originally Posted by DOOmsman

I tow and play up in the mountains and I'm going to hog out my jet soon. You may not see any improvement at altitude with a larger jet?

Oops, this is correct you would need a smaller jet if the altitude were high enough. Or you could increase air flow, and that is easy to do if you still have stock airbox. Make sure you read the plug there to see where you are at. Air is thinner at high altitude so you need more of it, or less fuel for a fixed amount of air such as carb size would dictate.

You should not have to touch your jet normally unless you increase airflow with intake air flow or exhaust mods. These small engines do like to run a little rich to make the most power so I like to see some definite tan on the plug. Mine is darker tan lol but I jetted it when it was cooler out. I hardly ever use choke, but it does not stink either. Well it is starting to stink now when it gets hot but that is due to wear not carb mixture....and I should be putting a clone in there soon to address that problem.

[JcXtreme72]

Thanks guys. Altitude here on the benches is right at a mile. I just figured I needed to open up the main jet since I have to run the choke full closed to be able to push the throttle past 1/2. I have a briggs opposed I built for my ezgo but I'm selling that so I think I'm just going to drop that into my G2 and not worry. It's built to 27hp right now so it should do great in there. On my ezgo with 8" of lift and 24" tires it pulled wheelies if you weren't careful. That was before I rebuilt it and modded for more power.