Photos – Donnie Bales  @donniebales28

My buddy Donnie Bales has really embraced his KX500 & was very excited to try the Rekluse Radius X Auto Clutch on our Motocross Action bike build.  

Check out the video to see us all having some good fun on an amazing bike.

For this build we started off with a very good used KX500 and went straight to KX Guru to find out what to do. I have worked with KX Guru on other KX500 custom projects over the years and trust their advice as they have learned some of the best ways to make a thirty-year-old machine perform close to a more modern bike. The KX500 stayed very similar over its years in production and was a desert and Baja championship machine. KX Guru has learned that when setting up a KX500 up for Motocross there are some somewhat easy modifications you can do to help make it more moto friendly.

Rado @dirtniron uses the throttle to warm me up with some KX500 Klotz smoke.

Since we shot this with Motocross Action our latest step was to add on a Rekluse Auto Clutch — that would help us keep the power to the ground and be much easier to ride on the track without stalling. It has changed the beastie bike to be just what we were hoping for. It is now easier to ride while still enjoy that 500cc’s of power.   

KX Guru starts with the swing arm modifications that enables the use of the larger 240mm KX450 rear rotor replacing the 220mm stock rotor which is one of the KX500’s weak links. Braking duties up front are handled by KX450 components that replace the antiquated stock equipment. All braking systems front and back are handled by top quality Galfer components.

Tom Morgan knows 2-Stroke engines and has the KX500 mastered. A De-Compression button makes starting the KX500 easier than a 250cc bike.

KX Guru took the frame and had it reinforced and strengthened in key locations with gussets copied from the old Team Green off road days and a few gussets designed and placed by KX Guru Racing. To keep the riders feet planted, custom foot peg mounts were machined and the stock right side KX500 peg mount cut off and a new custom mount fabricated and welded to the frame to accommodate the Raptor peg on the right. Rear brake lever mount modified for strength, durability and to utilize newer style KX levers.

V-Force Reed cage is a must on all 2-Stroke builds.

For the suspension, KX Guru Racing made up new Dogbones/linkage that were Team Kawasaki spec 132.5mm Dog-bones. They raise the back of the bike 10mm to place more weight on the front end to aid in cornering and also helps reduce the rate of speed at which the rear shock travels through its stroke in relation the rear wheel travel. This then reduces the bucking effect of the rear.

The Rekluse cover is off a KX450 that KX Guru modded to work. FMF still has pipes for the KX500.

For the front of the bike we bought 2011 KX450 forks and front end set up off of ebay for a good deal with the entire front brake set up. We had Applied Racing make up some custom clamps that are Hybrid clamps: KX450/KX500 Hybrid Triple clamps accommodate a KX450F front end swap while keeping the factory 22mm KX500 offset, uses the stock steering stops.

We also got a 1994 shock that is slightly more updated that Race Tech rebuilt and modified.  

The Faster USA wheels are for a KX450 but with our changes we can run them with ease.

KX Guru Racing makes their trademark two-piece clutch cover which allows easy access to the clutch (KX 500 stock cover requires lots of disassembly to perform this task). They also make a cool piece to replace the stock clutch arm and replaced it with a two-piece splined billet arm. This gives an additional 10mm of length which reduces the amount of force required to pull the clutch and provides more of a gradual clutch action at the lever. The clutch cable aluminum 90 degree sleeve was straightened out to approx. 45 degrees to reduce the number of sharp turns heading up to the lever. This results in reduced clutch pull effort.   

Decal Works custom graphics with a MotoSeat cover give us a great custom look.

KX Guru Racing Signature custom KIPS (powervalve) bolt modification. The factory KX500 exhaust valve drums sit over rotated in their normal state which result in the Aux. exhaust ports to be slightly open to help make starting the bike slightly easier.  This causes a slight hesitation in initial throttle response. The modified KIPS bolt prevents the drum valves from over rotating and keeping the Aux. exhaust ports closed when the power valve is not active.  This eliminates that initial hesitation resulting in snappier initial throttle response. 

Galfer Lines, rotors and pads are all updated to KX450 and have us with much better stopping power than a stock KX500.

Engine Modifications – Tom Morgan (TMR) took over the Engine Modifications by re-balancing the crankshaft, porting the cylinder and head mod. The head also gets a very cool decompression mod that not only aids in easier starting but reduces forces and load on engine internals that are no longer available from the OEM.

Rado loved the KX500 power and would have kept on riding it all day long if we let him. He was scaring us so we had to get him to stop before something bad happened to him or even worse to the bike.

ODI Champ Bend Podium Flight bars with V2 lock on Grips has us feeling way comfy at the controls.

John Duffy at Applied Racing made us some clamps a year or so before he passed away for this build and this is a great way we will be able to keep his memory close.

Race Tech took on the suspension work to somehow come up with a good KX500 setting with modern KX450 forks and they accomplished it very well.

KX Guru Racing/Alex Ward

38mm Keihin Quad Vent Airstriker. — — Keihin N82D needle Middle 52 pilot and 165 Main

Frame reinforcement/gussets- Scar Peg mounts welded on — Skid plate mounts

Rear brake lever mount modified to utilize newer style KX levers. 

Swing Arm mods to make KX450 rear wheel &brake work  

Clutch 2 piece splined billet arm 

Clutch Cover mod to accept Hinson cover for easier clutch access 

KX Guru Racing, Team Kawasaki spec 132.5mm Dog-bones— 

KX Guru Racing custom engraved ignition cover— 

KX Guru Racing Signature custom KIPS (powervalve) bolt modification 


Radius X Auto Clutch 

Outer Cover KX450

Pro X Racing Parts   

Clutch Basket

Clutch Inner Hub

Clutch Inner Hub Dampers

Steering stem bearing kit       

Linkage rebuild kit

Swing arm rebuild kit 

Carb Rebuild kit

Chain Rollers 

Throttle Cable

Clutch Cable

Chain Rollers 

Main Bearing kit

Front 14 Sprocket 

Rear 49 Sprocket  

MX Chain

Applied Racing                  

Custom KX450/KX500 Hybrid Triple Clamp to fit 2020 KX450 fender/number plate 20 or 22mm offset to fit 2011 KX450 forks 


Cylinder porting 

Head Mod and Decomp install 

Head De-comp Mod

Crank rebuild & Balance for less Vibration 


FMF Racing                                    

Exhaust and Custom modified silencer      

Wiseco Performance Products         

Piston Kit  

Clutch basket

Inner hub 

Pressure plate  

P3 Carbon  

P3 Carbon Skid plate-Modified to fix with custom welded on tabs

Cometic Gasket 

Engine gaskets

Galfer USA

Oversized Rotor/Adaptor Bracket KX450

Rotor rear KX450

Brake line rear  KX500

Brake line front KX450 2012

Brake pads KX450 Front & rear 


Faster USA  

Complete KX450 Wheel set  


Dunlop Tire  

MX33 front   

MX33 Rear  

Race Tech             

Suspension Re-Valve and set up— 1995 KX500 Shock & 2011 KX450 Fork

Uni Filter                 

Two-stage Air Filter   

MX Plastics 

Full plastic kit —

2020 KX450 front fender

2020 KX450 Front # plate  

Fork guards 2011 KX450

Shrouds KX500

Side # plates KX500

Rear fender KX500

Mud Flap KX500

Works Connection  

Hour Meter and Mount 


Clutch Perch assy 

Brake lever

Chain Blocks KX450

Brake caps front off of KX450  

Stem Nut

DeCal Works                                                  

Semi-Custom Graphics kit                    

Preprinted number plates backgrounds   


Ti Foot pegs off of KX450— Mounting kit welded on 

Klotz Synthetic Lubricants                   

R-50 Two-Stroke Pre-Mix


V-Force 2 Reed Cage – 


Radiator straightening and bracing

San Diego Powder Coating             

Sandblasting, powder with super-durable clear, and “race prep masking’  

Moto Seat                                         

Custom Cool seat cover

Fasst Co

Rear Brake Return Spring

Rear Clevis 

Specbolt Fasteners  

Engine and Plastic complete bolt kit 

VP Fuel  

C12 Fuel 


MX V2 Lock On Grips

Handle Bars  

Custom Bar Pad 


Hydroblasting and Cerakoting


Clarke Manufacturing

OEM style/sized Fuel Tank 

OEM or other Parts we need to buy that we have already —   

Carburetor from Sudco— 

KX450 Rear brake pedal  & rear brake lever, caliper -carrier from kx450f

KX450 forks- 2011 —with front brake set up

1995 rear shock 

Jay Clark/DBTV  

Parts to buy  RM ATV/MC -DBTV Shopping 

Instagram: @dirtbiketv1