I run a GX690 on a backwater SWOMP frame, and love it, except for thr fact that i can find ZERO performance parts for this engine most likely due to it being a fairly new model, and not widely used in kart racing .

even a high flow air filter adapter would be better than nothing. any knowledge out there?

go buy a gatortail!

shhhhh... jet jon. and the only reason i need performance parts is for when your boat is "too heavy" or gets stuck in a hard bottom and i have to give you a ride.

fair enough ill leave you alone but ill swim before I ride in your tin can!

That engine isn't a new model. Good luck finding perf parts for it. Woodiebuster had headwork and some other stuff done to his, I think. I ran one stock for 16-18 years (it all runs together, I don't remember anymore lol). It's still going. Easily well past 1000 hours with no mechanic work done to the engine cept for plugs and oil and a new switch.

Good luck, everything we did was shade tree custom work.

There are a few parts in the mini tractor pull and cart racing world. But they are for high rpm and rebuilt pretty regular.
I decked heads, port and polish, jetted the carb out, and built an exhaust.
It ran 23 on a heavy 3/16" 18x42