We’ve been riding the KTM300SX two-stroke for a few weeks now. It’s really fun and really fast. We love a bike that scares us a little! This is a very new bike; frame, engine, everything. One of the most superficial changes is the new displacement. There was no 300cc motocross two-stroke in KTM’s American line-up last year. There were 300cc off-road bikes and a 300cc kit for the 250SX motocross bike. More importantly, the new motor was designed around throttle body fuel injection. Transfer Port Injection and oil-injection remains only on the off-road bikes. Then there’s electric start and an electronic power valve, neither of which has b een used on KTM motocross two-strokes.

You would swear that the new 300SX is at least as fast as a modern 450 motocross bike. At low rpm, the 300SX has incredible pulling power. It’s almost startling, but that’s nothing compared to what’s waiting later. In the mid-range the 300 goes a little crazy. It hits hard, so you better be prepared. The motor pulls so hard and goes through the middle rpm level so fast that it’s usually best to chicken out and upshift early. For many parts of the track, you can upshift and let the torque do all the work for you. Then, once you’re strapped in and ready to go, you hit the clutch once or just wait for the fireworks to commence. It’s an absolute blast when you do it right. We all can’t do it right all the time which is why the 300SX has a maps switch. There are two buttons; one activates a green map and the other is a white map. Ride with the green map when you’re feeling strong and wanna have fun, then go to the white map when you’ve had enough. The white map tones down the hit considerably. It also shaves a little power off the top.

Pete Murray on the 2023 KTM 300SX two-stroke.

Interestingly enough, the 300’s peak power still isn’t a match for most 450s, even in the green map. According to the Pro Circuit dyno, the 300 makes 55 horsepower. That’s exactly the same as the Suzuki RMZ450, but about 5 horsepower less than the KTM 450SX-F, which was the dyno king in our 2023 450 shootout. Both of those 450s are easier to race than the 300, but probably not more fun to ride.

The Pro Circuit dyno revealed that the 300SX is still about 5hp shy of a 2023 KTM 450SX, which was the dyno king of our 450 shootout. The 300SX equaled the peak power output of the Suzuki RM-Z450.
The Pro Circuit dyno revealed that the 300SX is still about 5hp shy of a 2023 KTM 450SX, which was the dyno king of our 450 shootout. The 300SX equaled the peak power output of the Suzuki RM-Z450.

The 2023 KTM 300SX sells for $9199. That’s $1700 less than the 450SX-F four-stroke. You can read the full test of the 2023 KTM 300SX-F in our April, 2023 print issue of Dirt Bike.


Not all project bikes are good ideas. They are, by definition, experiments, and sometimes experiments go wrong. One such example was the Terrible’s Town XR650R, built by Gary Jones for a Best In The Desert race in 1999. The XR650R was a design success as a Baja racer, but weighed 288 pounds. We tried to shave off weight and improve performance as an off-road racer. One of the modifications was the installation of an inverted 47mm Showa dual-chamber cartridge fork. In the end, we worked like crazy and only lost 10 pounds. At the end of the story we said “You can go semi crazy and lose 10 pounds or you can go bonkers and lose 15. Or, you can leave the XR650R stock and just enjoy it. For what it is, it’s the best.”
We thought that was the end, but when the story was published, it ignited a firestorm of criticism from within Honda. It all revolved around the fork. Prior to the release of the bike, Bruce Ogilvie at Honda R&D had gone out on a limb, insisting on the conventional fork. He said it was superior for the bike’s mission. He was right, of course. When our project bike appeared on the cover of the March, 2000 Dirt Bike, memos flew back and forth within Honda. We met with Honda executives who told us we were not to build any more project bikes using Hondas without written approval beforehand. It all blew over, of course. It only took 10 years.


Travis Fant has been on a mission to expose all the factory secrets in 2023. This week he digs into RJ Hampshire’s Rockstar Husqvarna FC250. Husqvarna has had more time to test, figure out, and massage their FC250 heading into the 2023 season. Travis met up with mechanic Anthony Amos to go over all the trick parts, unique products, and custom pieces that make up RJ’s bike. He will have a complete report up on Monday. Check it out!


Saturday is the last day of the 2023 Mecum’s Las Vegas Auction. Prices are still high, but not as bad as they were in the middle of the pandemic. This Honda CR500 sold for $4950. The descriptions says it’s freshly rebuilt but does not have spark.

Sometimes bidding wars make things a little crazy. This 1976 RM250 was rebuilt entirely with original parts. It went for $19,250.  You can check it out for yourself at Mecum.com.

See you next week!

–Ron Lawson




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