KTM Parts On A Honda CRF250R? Yes, We Can!

This article was originally published in the December 2017 issue of Dirt Rider.

In last year's 2017 250F MX Shootout the Honda CRF250R placed fifth. As to why it didn't win, we wrote: "Every little bit of power helps, and the CRF's motor leaves something to be desired. And even with three chambers of air to mess with, we were never really happy with the fork." The winning bike was the Yamaha, and second was the KTM.

A well-known secret in the factory pits is that some teams use the KTM throttle body on non-KTM engines. We got to wondering what it would take to make this mod then see how it performed. While we were at it, we decided to throw on the winning bike’s fork to see what type of machine we’d wind up with. The Long Haul in this issue answers the performance question, but here’s the how-to on the way we did it.

The '17 250R is equipped with a 46mm Keihin throttle body that we opted to swap out for a 44mm Keihin throttle body that is standard equipment on a '17 KTM 250 SX-F. Not only is it 2mm smaller, but it also has a unique injector position that is mounted on the bottom of the throttle body. Many testers have reported that this injector angle and position has substantial benefit on throttle response and overall engine performance.

This mod requires substantial mechanical experience with a good understanding of how both the electrical and EFI systems operate. You will also need to have either the Honda PGM-FI programming tool or an aftermarket ECU along with its programming software.

Your parts list should include a complete throttle body assembly and possibly a wiring harness from the same KTM model the throttle body fits. You will need to have some fuel line available to extend and reroute the fuel line from the fuel pump to the fuel injector.

In addition to the throttle-body swap we decided to test a coil spring fork on the CRF250R. We felt that the Yamaha YZ250F KYB SSS fork is one of the best-performing stock forks on the market so selected it.

This fork swap, done this way with a complete front end available to us, was relatively easy. With basic to novice mechanical experience you could do this with a friend’s donor bike at the track one afternoon and test it yourself.

These are two mods that are slightly out of the ordinary for most people, but if you own a CRF250R that has been relatively unchanged for a few years now you might want to try. To see how the mods worked, check out the Long Haul update on page 74.