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  Hop Up Kit, GX340, GX390, 420 Predators, and 13/15hp Clones, Stage 4



 
Our Price: $759.00

Quantity in Stock:9991
Product Code: STAGE4KIT390

Choose Engine Type

GX390
420 Predator ( $30)
GX340
Head Casting (Application)

13 Hp Clone Head (Large Port)
Genuine Honda GX390 UT1, Large Port (Max RPM) +$30
Genuine Honda GX390 UT1, Large Port (Max RPM) w/40mm Intake $80
Genuine Honda GX390 UT2, Small Port (High Torque) +$30
Select Carburator

GX390 Bored - Gas
GX390 Bored - Methanol (+$10)
34 Flatslide Mikuni - Gas Only (+$130)
33 Mikuni Pumper - Gas (+$210)
33 Mikuni Pumper - Alky (+$274)
GX390 Marine Carb - Gas (+$60)
GX390 Marine Carb, Bored - Gas (+$80)
Header & Exhaust Options

No Exhaust
Add Header (+$45)
Add Muffler and Clamp (+$35)
Select Valve Springs

Single (250, 280, 306 cams)
Dual (307 and higher cams, Must cut the head)
Select Rocker Arm Type

Billet 1.3 Rockers (included in Kit)
Roller Rockers (includes Spacer) (+$170)
Select Camshaft

280 RPM (Mild cam for larger tracks)
280 TQ (Pulling cam)
306 RPM (Med to large tracks) BEST
306 TQ (Small Tracks)
307 RPM (33mm Carbs or Bigger Carbs)
320 0807 (not recommended)
250 Lift (OEM 390 cam) (+$90)
Select Flywheel Type

No Flywheel
Add Aluminum Flywheel - Recoil Start (+$180)
Add Aluminum Flywheel - Electric Start (GX390 Only) (+$220)

Add UT2 Coil w/o Rev Limiter, for UT2 Hondas Only ( $85)

Qty:
Description -
 

The 3 kit starts with package similar to that of the stage 2 kit but adds a Ported and Milled Head with stainless, stainless valves, stud kit, & HD valve train components.

Includes

  • · Race/Open Air Filter & Adapter,
  • · Choice of Carbs
  • · Choice of Cams
  • · Ported Head, Milled .100" (Clone)
  • · Stainless valves
  • · Aluminum Retainers & Split Keepers
  • · Chrome Moly Pushrods
  • · Single or Dual Springs
  • · 8 degree Timing Key,
  • · Billet Rod
  • · Carb, Head, & Case gaskets
  • · Stud Kit
  • · Billet 1.3 Rocker Arms
  • · Optional Roller Rockers
  • · 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.

Due to head work required, allow 1 week to ship.

Note: Use of the Choke Bracket requires use of a stock Honda (or Clone) "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

Aluminum or Honda flywheel recommended. Stock flywheels 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

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