What is the best way to increase speed/power on lt230e? Without any motor work. Example: carb tune/exhaust/sprocket change. Any suggestions will be appreciated.

 

If you don't want to open up the motor, than exhaust and intake are your best mods. The little 230 isn't a powerhouse, so only expect some modest gains. Changing sprockets will either give you better acceleration or better top end speed. They don't change power at all, just how the power is put to the ground.