GX340 & GX390 PERFORMANCE PARTS

Air Filter Adapter, 390 Code: AGK190 Price: $21.00 Available for delivery Quantity in Basket: none Fits GX390 & GX340. Precision CNC machined from billet aluminum. Incorporates venturi design. Accepts filter with a 2 7/16" ID.

Air Filter Adaptor & Air Filter Code: AGK190-CE4245ST Price: $35.00 Quantity in Basket: none Air filter adaptor with air filter. Our air filter adaptor is made from billet aluminum and incorporates a venturi design. The UNI filter is a dual layer, foam filter. This is a great washable filter suitable for all racers.

Main Jet, 390 Code: HON*** Price: $6.00 Quantity in Basket: none Choose from the following main jets for the stock GX390 carburetor: 100, 102, 105, 108, 110, 112, 115 & 118

Carburetor, GX390 Bored .925" Code: CS390CB Price: $99.00 Available for delivery Quantity in Basket: none GX390 carburetor bored to .925". Idle circuitry reworked. Great carb for GX390's needing more power.

Carb Insulator w/Vacuum Takeoff Code: HON16211 Price: $10.00 Available for delivery Quantity in Basket: none Replaces stock carb insulator. Use the vacuum takeoff to run a fuel pump.

Carburetor Adaptor With Pulse Fitting Code: AGK292 Price: $39.00 Available for delivery Quantity in Basket: none Precision CNC machined from billet aluminum. Very light weight. A section of hose is needed to attach carb (not included). Adapter is 2" in length. Hose mounting surface has a 1 9/16" OD. Drilled and tapped for a pulse fitting to run your fuel pump. Pulse fitting and two mounting bolts included.

32mm Mikuni Carburetor Code: AGK7320 Price: $150.00 Available for delivery Quantity in Basket: none This high quality Mikuni carburetor works great on modified GX340's and GX390's. This carburetor offers more horsepower and torque over the Honda carburetors along with the adjustability of a performance carburetor. Easy to install due to Mikuni's simple throttle cable setup.

Main Jet for 32mm & 34mm Mikuni Code: SUD*** Price: $6.00 Quantity in Basket: none Main jet for 32mm & 34mm Mikuni carburetor. Choose from the following sizes: 175, 180, 185, 190, 195, 200, 210, 220, 230 & 240

Pilot Jet for 32mm & 34mm Mikuni Code: SUD***PJ Price: $8.00 Quantity in Basket: none Pilot jet fits our 32mm & 34mm Mikuni carburetor. Choose from the following sizes: 30, 32.5, 35, 37.5 & 40

ARC Billet Rod, 390 Code: ARC6272 Price: $145.00 Available for delivery Quantity in Basket: none The stock rod is the weak link in your engine. Protect your investment with this high quality rod and bearing set. A must have with all big horsepower and high rpm applications.

Bearings, Replacement for Billet Rod 6272 Code: ARC6391 Price: $22.00 Available for delivery Quantity in Basket: none Replacement bearings for billet rod 6272.

Piston, Flat Top, Standard Bore 390 Code: HON390FT Price: $138.00 Available for delivery Quantity in Basket: none GX390 flat top piston for a standard bore. Piston rings not included. This is a stock GX390 piston that has been milled to a flat top.

Piston, Forged Flat Top, 390 Code: ASFFT390 Price: $150.00 Quantity in Basket: none OUT OF STOCK. PLEASE CALL Forged flat top piston comes with wrist pin and clips. Uses factory piston rings (not included). Use a finished bore size of 3.465".

Rings, Standard, 390 Code: HON130119 Price: $25.00 Available for delivery Quantity in Basket: none Standard ring set for the GX390 piston. Fits the flat top piston listed above.

Rings, File Fit, Standard Bore Code: HON130109 Price: $28.00 Available for delivery Quantity in Basket: none Over size rings used for file fit in a standard bore.

Cam, Custom Ground .315" Lift, GX390 Code: AGKCAM315 Price: $168.00 Sorry, we are currently sold out of 'Cam, Custom Ground .315" Lift, GX390'. Please check back later. Quantity in Basket: none GX390 Racing Cam .315" lift and 260* duration @ .050" lift. Hard face welding is used for protection against lobe wear. This cam has a great balance between low end torque and top end power. Upgraded valve train is recommended. You may need to clearance the inside of the cam lobes for the crank to pass.

Cam, Custom Ground .350" Lift, GX390 Code: AGKCAM350 Price: $168.00 Sorry, we are currently sold out of 'Cam, Custom Ground .350" Lift, GX390'. Please check back later. Quantity in Basket: none GX390 Racing Cam .350" lift and 223* duration @ .050" lift. Hard face welding is used for protection against lobe wear. This is the ultimate low end torque cam. Be prepared to upgrade your clutch to handle this cam. Upgraded valve train is recommended. You may need to clearance the inside of the cam lobes for the crank to pass.

Cam, Custom Ground .360" Lift, GX390 Code: AGKCAM360 Price: $168.00 Sorry, we are currently sold out of 'Cam, Custom Ground .360" Lift, GX390'. Please check back later. Quantity in Basket: none GX390 Racing Cam .360" lift and 260* duration at .050" lift. Hard face welding is used for protection against lobe wear. This is a big cam for the hardcore GX390. Upgraded valve train is recommended. You may need to clearance the inside of the cam lobes for the crank to pass.

ARC Racing Billet Flywheel, 390 NEW Code: ARC6623 Price: $195.00 Available for delivery Quantity in Basket: none This billet flywheel is very light at 4.7lbs. ARC flywheels use a Neodymium (rare earth) magnet which is the most powerful magnet on the market. Non-adjustable hub. Use flywheel key to adjust timing. Flywheel does not come with a ring gear. Without the ring gear, you will either have to use a handheld starter, or install the starter cup to be used with the pull starter. Uses stock Honda coil. No need for coil bracket and aftermarket coil. Just bolt-on and go! Very high quality. Must have item for any serious GX340 or GX390.

Cylinder Head, 390, Ported & Milled Code: AGKHPM390 Price: $178.00 Sorry, we are currently sold out of 'Cylinder Head, 390, Ported & Milled'. Please check back later. Quantity in Basket: none Cylinder head ported and milled. Increased flow and velocity from our porting makes this head an excellent choice for performance and value. Highly recommended performance upgrade for the racer looking to take his/her GX340/GX390 to the next level.

Robertson Straight Header Code: SM390H Price: $47.00 Available for delivery Quantity in Basket: none Robertson Straight Header (1.025ID x 15"IL). Accepts 1 5/16" silencer.

Robertson "Supersnake" Header Code: SM390SUS Price: $64.00 Available for delivery Quantity in Basket: none Robertson "Supersnake" Header (1.050ID x 23"IL). Accepts 1 5/16" silencer.

Silencer, RLV Code: SM410*** Price: $37.50 Quantity in Basket: none RLV silencer. Choose from three sizes: 1", 1 1/8" & 1 5/16". High quality clamp on silencers. Clamp sold separately.

Clamp for Silencer Code: SM414*** Price: $8.00 Quantity in Basket: none Clamp for RLV silencers. Choose from three sizes: 1", 1 1/8" & 1 5/16".

Stainless Steel Intake & Exhaust Valve, 390 Code: AGKS31EX-AGKS35IN Price: $65.00 Quantity in Basket: none These stainless steel valves replace the stock size valves. Longer than stock (+.250") to accomodate high lift cams. Must use aluminum retainer/keeper set and lash caps.

Retainer & Keeper Set, 390 Code: AGKSRET390 Price: $32.00 Sorry, we are currently sold out of 'Retainer & Keeper Set, 390'. Please check back later. Quantity in Basket: none This retainer and keeper set is designed to be used with our stainless steel 390 valves. Will not work with stock valves.

Lash Caps, 6mm, 390 Code: AGKE207 Price: $15.00 Available for delivery Quantity in Basket: none Lash caps are required for our stainless steel valves. These are 6mm lash caps designed for our OLD stainless steel valves. Will not work on stock valves. Price includes two lash caps.

Valve Lash Caps, 390, OEM Honda Code: HON14781390 Price: $10.00 Available for delivery Quantity in Basket: none Lash caps help prevent valve wear. They also provide a larger surface area for the rocker arm. Use with stock exhaust retainers on both stock valves. Price includes two lash caps. OEM Honda lash caps.

Retainer for Exhaust Valve, 390 Code: EEVR390 Price: $5.00 Available for delivery Quantity in Basket: none Stock exhaust valve retainer. Use on stock intake valve to accomodate lash cap.

Rev Roller Rockers, 390 Code: AGKRR1*390 Price: $215.00 Quantity in Basket: none 1.3 ratio is on backorder. Honda (or clone) GX340/GX390 billet roller rocker arms designed and engineered to withstand the valvetrain stress of a modified motor. dyno tested and race proven ratio rockers choose 1.2 or 1.3 rocker arm CNC machined from 7000 series alloy low rotational inertia mass due to super light arm design bearing grade brass bushings reduce rotational friction precision ground and hardened roller tip provides ultra smooth rotation ground and hardened alloy steel rocker shaft design eliminates valve train deflection cupped lash adjusters with ARP 12 point fastener

Valve Cover Spacer, 390 Code: AGKRR390S Price: $55.00 Quantity in Basket: none Use this valve cover spacer to provide clearance for our roller rockers. New bolt included. CNC machined from billet aluminum.

Chrome Moly Push Rods, 390 Code: AGKPR390 Price: $30.00 Available for delivery Quantity in Basket: none Chrome moly push rods are highly recommended when using an AGK racing cam.

Chrome Moly Pushrods Unassembled, 390 Code: AGKPR390U Price: $30.00 Available for delivery Quantity in Basket: none Cut to size chrome moly pushrods. Assembled length is 6.680".

Guide Plate, Push Rod Code: AGKE317 Price: $12.50 Available for delivery Quantity in Basket: none This guide plate has larger slots to accomodate the chrome moly plush rods.

Valve Spring, 32lbs Code: AGK32LBSVS Price: $10.50 Available for delivery Quantity in Basket: none The 32lb valve springs. Recommended for mild motors using stock cam. Change quantity to two if you want two springs.

Valve Spring, 55lbs Code: AGK55LBSVS Price: $10.50 Available for delivery Quantity in Basket: none 55lb single spring. Install height 1.200" with 90 to 95lbs open pressure. Use with mild cams. Change quantity to two if you want two springs.

Valve Spring, Dual, 50lb Code: AGK50LBDVS Price: $15.00 Available for delivery Quantity in Basket: none Dual valve spring for high output motors. Install height 1.300" with 50lb seat pressure. 120lbs open pressure. Coil bind at .600". Change quantity to two if you want two outer and two inner springs.

Shim, .029" Code: AGKE356 Price: $1.15 Available for delivery Quantity in Basket: none Use these shims under the valve spring to obtain proper install height.

Lifter, Stock GX390 Code: HON14441 Price: $11.00 Available for delivery Quantity in Basket: none Genuine Honda GX390 lifter. Big block motors in the 50hp range are wearing out the stock clone lifters. Use this genuine Honda lifter as a replacement. Sold individually. Change quantity to 2 if you want 2.

Gasket Set, 390 Code: CS390GS Price: $26.00 Available for delivery Quantity in Basket: none Complete engine gaskets set for GX390. Includes head, side cover, valve cover, exhaust and both intake gaskets.