CUSTOM YAMAHA RAPTOR WITH AN MT-07 ENGINE

The road to "numb bum" glory: One man's build of the ultimate endurance racing quad

On Apr 15, 2023

THE ROAD TO NUMB BUM GLORY: ONE MAN’S BUILD OF THE ULTIMATE ENDURANCE RACE QUAD

“I saw your article with the 300SX powered Yamaha and I though I’d send you our version of an awesome Raptor that we feel Yamaha should make!” wrote Taren Krisher. We quickly agreed that it was an impressive build that deserves a story. Krisher and his team have been ice racing ATVs for many years now. In fact, he’s been at it for 22 years on his own. In that time the team has raced a variety of machines, but mainly racing the same two Raptors since 2011. More power without sacrificing reliability has always been the goal. They salvaged a 2019 MT07 engine and put it into a Raptor frame. The result is a high-performance ice racing machine that they call the Veloci-Raptor.

yamaha raptor with mt 07 motor — ***It took a lot of extra work and creativity to get this engine to sit in here nicely and look almost just like a stock Raptor.***

Ice racing is an exhilarating winter sport where bikes and quads with studded tires race around an F1 style track on a frozen lake. “These Raptors have been ideal for endurance racing with their flat torque curve and approximately 50 horsepower, achieved with intake and exhaust modifications,” said Krisher.

yamaha raptor frame — **The chassis had to be modified to accept the new street mill.**

“A 740cc big bore motor was sitting in the Blue Raptor, which gave us great power, but the bottom end couldn’t hold up and it failed on us twice, splitting the case and destroying the engine,” Krisher continued. “So, we returned to racing stock engines. For many years, we wanted to build a machine with more power, but not a monster machine like an R1 that gives you 180hp that you can’t really use.”

With the MT07 engine removed from the wrecked street bike, fabrication began to stuff the new powerplant in the frame cradle so that the plastic bodywork and tank would still fasten in the stock locations. At a glance, it still looks like a regular Raptor. “After cutting the frame apart and building new motor mounts and frame rails, we completely stripped down the MT07 wiring harness, removing the ABS circuits, signal lights, and numerous sensors, and wired all required systems back to the stock Raptor handlebar switches,” claimed Krisher. “Lining up all of the electrical components and wiring was one of our biggest challenges.”

But the build wasn’t finished yet. “We used the Aftermarket Fuel Customs intake and airbox that works so well to feed air to a Raptor, and modified it to accept the dual intakes of the MT07 throttle bodies,” said Krisher. “We kept the MT07 exhaust header, but cut out the restrictive cat and muffler, running a straight pipe to a monster exhaust can. The result is a very distinctive roar when you roll on the throttle.””

The modifications to the intake and exhaust, as well as a CPU flash to increase fuel delivery, have resulted in a machine that pulls smoothly and strongly. After making adjustments to the gearing as needed, Krisher’s team competed in a few winter events and managed to place 2nd overall after three races.

Krisher told us the goal for this machine is to make an ultimate Numb Bum racer. “The Numb Bum is a Guinness world record 24-hour endurance ice race where teams compete, one rider at a time, swapping out to run the machine non-stop for 24 hours. One lap is typically 10 miles long, so in a 24-hour period we normally rack up about 1000 miles, so having a machine that can run reliably is essential,” claims Krisher. “We still need to make suspension adjustments and other minor tweaking before the next Numb Bum, but we believe we have built a very solid, reliable racer that will help us achieve our goal of making the ultimate Numb Bum racer.”