Hop Up Kit - GX340 - GX390, 420 Predators, and 13/15hp Chinese OHV, Stage 2/3
As step up from the Stage 1, this kit is designed to improve the power for the GX340s and GX390s along with improving the durability.
Race/Open Air Filter & Adapter
- Choice of Carbs
- HD Valve Springs
- Offset Timing Key
- 280 Lift Cam
- Reinforced Rockers
- Billet Rod +(.040 longer)
- Carb and Side Cover Gaskets
- Optional Header/Exhaust
- Optional Aluminum Flywheel
Picture for reference only and may show optional parts. See above description for actual content.
Header not included unless specified.
Note: Use of the Choke Bracket requires use of a stock Honda (or Chinese OHV) "Air Filter to Carb Gasket". This is not included in the kit. You can use the one that came with the motor, or can purchase one at
Filter should be sprayed with K&N type oil, especially in dirt applications. Oil not included click here
Billet Aluminum flywheel recommended. Stock flywheels, esp "Clone" are prone to
failure and very DANGEROUS
Note: UT2s series Hondas (2012 & up) or later have a built in Rev Limiter in the coil and will require a new coil to exceed 4000 rpm. The UT2 coils (4 wire) can only be used with stock flywheels.
If using a Billet Flywheel, you must run a UT1 style coil (single wire).
13/15 Chinese Engines (414, 420, 460) usually have UT1 style coils already. However some Lifans and 420s have a digital ignition and will need a Honda UT1 coil to run t he billet flywheel.