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Main Jet Performance Upgrade Kit For GX390 and Predator 420cc Main Jet Performance Upgrade Kit For GX390 and Predator 420cc

Our main jet kit is a must for the Honda GX390, Predator 420cc engines that have had the performance K&N style air filter setup installed on the engine. Maximizes the engine for best performance and air fuel ratio.

Our Price: $8.14
Header Kit, GX390 Mud Motor Header w/Muffler Straight Header Kit, GX390 Mud Motor Header w/Muffler Straight

Mud Boat header kit that fits the big block Honda GX240, GX270, GX340, GX390, Predator 420cc and 460cc engines. Our header kit features 1 1/4" O.D. header tube and is TIG welded for best durability. Our header kit includes the following components:

  • Straight header tube to fit mud motor specifically
  • Our custom TIG welded header flange
  • Screw on muffler

Our Price: $36.00
Header Kit, GX390 Mud Motor Header w/Muffler Angled Header Kit, GX390 Mud Motor Header w/Muffler Angled

Mud Boat header kit that fits the big block Honda GX240, GX270, GX340, GX390, Predator 420cc and 460cc engines. Our header kit features 1 1/4" O.D. header tube and is TIG welded for best durability. Our header kit includes the following components:

  • Header
  • Our custom TIG welded header flange
  • Screw on muffler

Our Price: $38.00
Bullfrog Pro Velocity High Performance Air Filter Kit for Honda GX390 Bullfrog Pro Velocity High Performance Air Filter Kit for Honda GX390

Our Pro Velocity high performance air filter kit fits Honda GX340, GX390, Predator 420cc and 460cc big block clone engines. Upgrade your go kart, mini bike or drift trike with our high performance air filter kit. Our kit includes the following items:


  • High flow racing style air filter 4" filter length
  • Foam Pre-Filter
  • Radiused air filter adapter
  • Choke hold bracket

Our Price: $44.95