Any bolt-on upgrades that would help squeeze a bit more power out of my GX motor? It looks like this is a fairly popular karting engine, have found a few parts, carbs, cams etc. online... anyone have any experience that can vouch for the results of these upgrades? - Im not looing for 1/10th of a second on the track but hopefully some noticable difference in speed and push through the muck...

Get a candy cane header and rejet the carb. Also add an aftermarket air filter/more open. Then pull out the governor if you haven't already.

I have looked at this question long and hard for several years. If you're going to mess with your motor:

There are some good tutorials on affordable go karts web site

put a tack on it. stock components will generally go to 5,000 Rpm with out a problem. A tack will keep you out of trouble , they are cheep and give invaluable feed back.

up grades are worthless with the governor still in the motor.

the most bang for the buck comes from a more free flowing exhaust.This is next after a tack.

You should rejet the carb to get the max out of exhaust improvements. This is just a bit of fiddleing to do and costs maby $5 - 6.

after the above you will probably need a new prop to take advantage of the difference. This is likely to be the most expensive part of the up grade.

Mark F. Cheney