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Hop Up Kit: GX340, GX390, 420 Predators, and 13/15hp, Stage 1
Hop Up Kit: GX340, GX390, 420 Predators, and 13/15hp, Stage 1


 
Our Price: $59.99

Stock Status:In Stock
Part #: STAGE1KIT390

Choose Engine Type

420 Hemis
420 Old Style, 460s, & 13/15 Clones
GX390 UT1, 2011 or earlier
GX390 UT2, 2012 or Later
Header & Exhaust Options

No Exhaust
Add Header, Kart & Mini-Bike [+$37]
Add Header, Muffler, and Clamp: Kart & Mini-Bikes [+$75]
Add Mud Motor Header & Muffler (390) [+$42]
Additional Options

Add Twister Cam [+$56]

Add UT2 Coil w/o Rev Limiter, for UT2 Hondas Only [+$67]

Qty:
Description -
 

Basic kit for improving the performance of GX390s, 420 Predators, 13/15 hp Chinese OHVs. Simple to install, you can expect significant performance increases.

Stage 1 Kit includes

· Race/Open Air Filter & Adapter,

· HD Valve Springs

· Offset Timing Key,

· Main Jet for application (see Notes)

· Pilot Jet

· Choke Hold Down Bracket

· Optional Header/Exhaust

· Optional Carbs (includes insulators)

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


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