Predator 420 Stage 1 Performance Kit, fits GX340/GX390, 420cc Predators

  • $129.95
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Stage 1 Kit

GX340/390/420 Predator

Basic kit for improving the performance of GX390s, 420 Predators. Simple to install, you can expect significant performance increases.


  • Race/Open Air Filter & Adapter
  • HD Valve Springs
  • Offset Timing Key
  • Main Jet for application (see Notes)
  • Pilot Jet
  • Choke Hold Down Bracket


  • Exhaust Header (Optional)
  • Camshaft (Optional) 

Picture for reference only and may show optional parts. See above description for actual content. Header not included unless specified.

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) have Rev Limited coils and will require a new coil to exceed 4000 rpm. The UT2 coils (4 wire) can only be used with stock flywheels or 6693 ARC flywheels. If using any other Flywheels, you must run a UT1 style coil (single wire). Most 390 clone, 420s, and 460s have UT1 style coils already (However some Lifans and 420s have a rev-limited digital ignition)

The difference in the Kits is the main jet. We recommend you check the check your STOCK main . If stock main is a :

· #92 thru 97, use a UT1 kit,

· #98 thru #102 use a Hemi Kit

· >102, Use a UT2 kit

Manufacturers have been know to use different jets on the same models. So it is important to know the stock jet size