2010 KTM 450 SX-F – First Test – Dirt Rider Magazine

The KTM 450 SX-F is in a class by itself. As the only electric-start motocross-specific machine, it clearly holds some interesting conveniences and advantages over the rest of the bikes in the crowded, often cookie-cutter world of moto. Looking back a couple of years you might think you see an identical match to the 2010 model, but you’d be greatly mistaken. This year’s SX-F has a host of changes that work and work well. These are improvements to a machine that nearly won our 2009 450 MX shootout. Depending on the polarity KTMs seem to ignite among riders not accustomed to riding them (it’s a love-hate thing) it could be the bike to beat in 2010. And who’s to say it isn’t for you?

This bike is well known for a few things, first of which is its motor. Unlike Kawasaki’s arm-ripping snap, the KTM is regarded as a smooth producer with a linear pull and a never-ending top-end carryover. The bike makes gobs of power and dishes it out in a wide swath. What it hasn’t had is snap or hit. What it has had is ultimate traction. This transfers into the handling as well. Corners are rarely done more smoothly than on the KTM, and the front end seems ultra-planted for almost every test rider who jumps aboard.More good traits follow KTMs across the country. There are the incredible durability track records, tales of supreme ease-of-use-especially when wrenching (note: add 13mm wrenches and torx bits to your toolbox)-and the impressive list of eye-catching stock parts that will be bolt-ons for the other brands. Want a magnetic drain plug? It’s stock on the KTM.For 2010, KTM stayed close to its 450 past but made a push forward in a few key areas. Most noticeable on the track is the addition of a five-speed transmission. The four-speed was more than adequate on the Katoom since the bike produces such good power-lugging corners in third and letting it pull out was easy. But with the XC line’s five speeds a new sort of aggression unfolds. The bike is able to rip or lug through a turn. The bike can rev high-so high you’d swear you’re on the rev-limiter-or you can short-shift and enjoy the healthy midrange. The 2010 450 SX-F is two words better than the 2009 and previous versions: more versatile. However, second gear does seems a little short for multiple corner use, and if you’re in it, get ready to shift soon to third on any exit with a hint of straightaway. You could always stay in third and forget about shifting, just use the brilliant hydraulic clutch.The next noticeable change is in handling. KTM changed some dimension on the new 450 by welding the frame 10mm lower on the head tube. That, combined with a 4mm shorter shock, brings the back of the bike 10mm lower when measured from the axle. The seat-to-peg dimensions are the same, but the line from shock tower to head tube is less straight. KTM says this helps absorb energy from shock impacts as they travel to the front of the bike. Only a few years ago the fork felt ridiculously harsh on these models.With the addition of more flex in fork tube material a few years back and changes like this backbone bend to the frame, KTM has virtually eliminated the harsh feeling. There are also internal changes to the fork that KTM is staying tight-lipped about. In all, the bike provides a nice ride with less bucking and rear-wheel influence felt in the handlebar. In fact, the shock is probably the best we’ve felt on a KTM in a while. It really shines while accelerating out of corners. It eats acceleration chop and nasty holes and keeps the tire on the ground and moving forward.Don’t forget about the carburetor. Yes, the 450 SX-F still has one. Why? We don’t know. But our guess is KTM is building a bike around fuel injection and is not in a hurry to simply bolt it on. Remember: this bike lost a pound when it gained electric start as part of its transition from ’06 to ’07. But what the carburetor gains is a leak jet and updated jetting to go with it. The combo produces a power delivery that has more snap and hit than previously but manages to keep the rear wheel behind you. The power feels pumped up for sure thanks to the new jetting specs. Or maybe it’s that thing on the header pipe…Actually, that “thing” on the header pipe is claimed to be a noise resonance chamber. That means it’s for sound, and KTM says it’s not a “power thing.” The bike does sound great-quiet but with plenty of muscle.Specifications

MSRP: $NA

Claimed dry weight: 231 lb

Actual weight (no gas): 236 lb

Seat height: 38.8 in.

Seat-to-footpeg distance: 21.0 in.

Footpeg height: 17.8 in.

Fuel capacity: 2.1 gal.What’s Hot!

Traction (front and rear)

Power (bottom and top) and the five-speed gearbox

Cornering (flat track or tight ruts)

Beautiful SXS brake caliper, hydro clutch, e-start, easy-access air filter, captive wheel spacers, durability, quality, stickers, etc.What’s Not!

Can stall if you try hard enough with your whacky throttle hand.

Ultra-cool EFI is missing.

Remind me to charge my battery before cold mornings…no kickstarter!

5’10″/165 lb/Pro

The first thing that I noticed on the new KTM was the turning characteristics. For me, last year’s bike had some front-wheel tucking issues on flat track turns as well as the front-end feeling busy. This year’s bike is a lot more stable and has really good traction control and feedback in the front end as well as the rear. Another thing I noticed was how well the rear of the bike tracked under a load on acceleration bumps. Very confidence inspiring when you’re approaching those doubles through massive acceleration chop! The next thing is the new five-speed transmission. The motor on the KTM 450 has always been super strong and easy to ride. It has good response and delivery as well as great top-end overrev. But I felt that having a four-speed transmission hindered the bike on certain tracks. It was great on more wide-open tracks, but it was a lot of work trying to use the horsepower on smaller, tighter tracks. With the new five-speed it was easy to control and trim the endless horsepower the KTM motor puts out-even on tighter tracks such as Perris Raceway. Overall, my first impression of the 2010 KTM 450 SX-F is that it’s a definite improvement!Jimmy Lewis

5’10″/185 lb/Vet Expert

This may be shocking news, but the 450 SX-F may just have the best 450cc motocross engine I’ve ever ridden and that includes works bikes I’ve sampled, too. High praise, you bet ya, but some of the small changes the engineers did really complete the package, fifth gear included. The pipe and muffler (really quiet, too!) somehow make the motor more aggressive when you want it and smoother when you need it. Plus, I love electric-start anything. Add to that the chassis changes that go way beyond what I thought they’d amount to with extra weight on the front wheel. Accomplished with I don’t know what, since they coppered out the bike with a shorter shock in the rear. It is a go-where-you-steer-it package that’s more stable than ever. Slow it all down with a works-quality front stopper (which I love) that will do nothing but draw complaints for being too strong come shootout time and you have the best KTM motocross bike ever. So I’m guessing they have an all-new one coming out next year? Exactly the plan when you get an old design refined to top level…