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BIG BLOCK GX340 - GX390, 420 Predators, and 13/15hp OHV, Stage 1

BIG BLOCK GX340 - GX390, 420 Predators, and 13/15hp OHV, Stage 1

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Choose your options:
Header & Exhaust Options(optional):
Add Silencer And Clamp(optional):
Additional big Block Options(optional):
Kit Filter Option(optional):
Add Heavy Duty Springs(Recommended)(optional):
Add Advanced timing Key(optional):
Add Flywheel(optional):
Add UT2 Coil(optional):
Product Code: STAGE1KIT390

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,

·Main Jet for Application (see Notes)

·Pilot Jet

·Choke Hold Down Bracket

·Choice Of Header/Exhaust

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

Filter should be sprayed with K&N type oil, especially in dirt applications. Oil not included

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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