MXA RIDES THE 72-HORSE KTX500e TWO-STROKE: ONE-THIRD KX500, ONE-THIRD KTM & ONE-THIRD HAND-MADE

The KX Guru Racing crew built this third-generation big-bore KX500 two-stroke—they call it the KTX500e. Everything about this machine was custom. KX Guru Racing took the blueprint from Sean Collier’s championship winning KX500 and tweaked it to make the power a broader, four-stroke-like powerband. They called it the “Sean Collier Stage 3” engine. They started with a set of TSR crankcases (which included a hydraulic clutch) and a two-piece clutch cover from Australia. The crank was also stuffed by the Rouse family, then sent to Parris Concepts for the induction modifications. After all the crank work was complete, it was mated to a hand-polished Wossner rod. Then, they added a Boyesen KX250 water pump and impeller. Adam Miller built them a custom head for the KX500 that used the KTM radiator hose fittings and re-chambered it to KX Guru Racing’s specifications. A bulletproof Hinson basket was used with all its supporting hardware to support the extreme power of the 500cc powerplant. For the carburetor, they went with a Keihin quad-vent Air Striker and a custom MRE reed holder system for the Moto Tassinari V-Force 2 reed cage. This beast produced 72 horsepower on the dyno. And yes, we felt every bit of it on the track. The eye-watering power was intense to say the least. It was a total adrenaline rush to hold the throttle to the stops heading into Glen Helen’s steeply banked Talladega first corner.

You might have guessed that the “e” stands for electric start. DeCal Works customized the graphics. Works Connection supplied the titanium fasteners, skid plate and more. Renthal supplied the chain and sprockets. TuBliss tubes were used. Faster USA laced up Excel A60 rimes on their custom green hubs with stainless steel spokes. Twin Air provided the air filter. Motomaster added in the oversized front rotor and braided stainless steel brake lines. Guts Racing built the seat. TM Designworks added the bulletproof chain guides. CRM Karbotank did the tank, and Motogear Speed shop pitched in. MXA’s Josh Mosiman did the riding for the video and is here to tell you what it was like to ride.