i need more power any advice?????

[thatoneguy]

well i got the big bore kit in its runnin awesome but im a guy and most guys want more power in their off road toys and i was wonderin if you guys knew of any way i can get more power/torque outta my motor do i change the roller weights go lighter like 10-9 gram weights or what? but at the same time i dont want to sacrifice too much of the top end maybe a high lift racin cam, ported head, idk everything on motor is bone stock except exhaust, carburator, and cylinder/piston. if you have any tips or advice i would love to hear it thanks

[90GTVert]

Transmission/roller tuning doesn't really make more power, just makes better use of the power you already have. Lighter weights keep the engine revs higher and can improve acceleration. Too light can lower your top speed. Way too light will keep the revs higher than the powerband and decrease acceleration. Heavier weights ensure that your variator reaches it's full travel to get more speed. Too heavy can decrease acceleration. Way too heavy can make it an absolute slug that has no power to get to a higher speed.

You could change one or both of your drive sprockets (axle and engine output) to change your gear ratio to get more acceleration or more top speed, depending what you're looking for and what your engine can handle.

A higher lift and/or duration camshaft could help and they aren't too expensive.

A ported head is another good option. Even if you don't feel safe tackling a port job, maybe port match your intake, spacers, gaskets, head, and exhaust. Making more compression will create more power. If you check you piston to valve clearance, you might find that you are able to have the head milled to increase compression. This may require the use of higher octane fuel. It's pretty common to see people milling head .010" - .015" using premium pump gas without issues. You definitely wanna check clearances with whatever cam you'll be using first though.

You could advance the ignition timing to get a little more power and throttle response. You can do that using an aftermarket advanced timing CDI or by modifying your pickup coil's mounting holes so you can move it to change the timing. This may also require a higher octane fuel. Always etch the coil's mounts so you know exactly where the timing was stock.

Spend some time tuning the carb. Dropping in a jet per someone's suggestion is often a great starting point, and sometimes is the best jet for the job, but not always. Sometimes even going the next size up or down in main jet size can make quite a difference. Of course spend time getting the idle settings and needle settings correct for good response and low-mid throttle power as well.

[90GTVert]

Here's some info from stepthrutuner that you might find interesting. It's about the 50cc version of the GY6, but much of it pertains to the bigger 125cc+ versions as well.

49ccscoot.proboards.com/index.cgi?board=4ttech&action=display&thread=407

[Fox]

Yeah, an engine is just an air pump if you get down to the basics of it. The gas just powers the pump. The only way to increase performace is to increase displacement (of air) so like Brent said porting is how you increase air flow coupled with a camshaft that opens the valves a little more and a little longer and a bigger carb/pipe and taller gears in the rear etc...but when you get into all of that stuff it has to be a labor of love otherwise it's cheaper and easier to just get a 250 or bigger and be done with it. They even make a 4 valve head for 125/150cc GY6 but they are like $200.

There's some good info here too:
www.rc-trucks.org/gy6-engine-performance.htm