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Hop Up Kit; GX340 to GX390, 420 Predator, & 13/15hp OHV; Stage 2
Hop Up Kit; GX340 to GX390, 420 Predator, & 13/15hp OHV; Stage 2

Our Price: $177.00

Stock Status:In Stock

Part #: STAGE2KIT390

Select Flywheel

No Flywheel
Add Aluminum Flywheel - Recoil Start [+$166]
Add Aluminum Flywheel - Electric Start [+$211]
Ignition Coil Option

Add UT2 Coil without Rev Limiter, for UT2 Hondas Only [+$65]
Add Genuine Honda UT1 Coil [+$38]
None Included
Header & Exhaust Options

No Exhaust
Add Header- Kart & Mini Bike [+$43]
Add Mud Motor Header & Muffler (GX390) [+$46]

Description -
Stage 2 Hop Up Kit for GX340-GX390, 420 Predator, and 13/15hp OHV Engines
As a step up from the Stage 1, this kit is designed to improve the power and durability of GX340s and GX390s.

  • Race/Open Air Filter & Adapter
  • 23.5mm Honda Race Carb (Bored)
  • Heavy Duty Valve Springs
  • Offset Timing Key
  • Twister Camshaft
  • Carb and Side Cover Gaskets
  • Optional Header/Exhaust
  • Optional Aluminum Flywheel
  • Optional Valve Cover Gasket for Hemis
*Note: Use of the choke bracket requires use of a stock Honda (or Chines OHV) "Air Filter-to-Carb" gasket. This is not included in the kit. You can use the one that came with the motor, or you can purchase one from us here.

UT2 series Hondas (2012 & up) or later have a built-in rev limiter in the coil and will require a new coil to exceed 4000rpm. 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 the billet flywheel.

Header not included unless specified.

Filter should be sprayed with a K&N type oil, especially for dirt applications. Oil not included - click here.

Picture is for reference only and may show optional parts. See above description for actual content.

Warning: Billet aluminum flywheel recommended. Stock flywheels, especially "clones" are prone to failure and are very dangerous!

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