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2017 KTM 250SX | Back End | Bike Reviews | Features

TWO-STROKE MOTOCROSS tragics who’ve been lying awake at night worrying about the future of their beloved smoke machines must have heaved a sigh of relief.

News came through from Austria that the SX two-strokes were not getting injection, at least not yet. Ditto the Huskies.

“Transfer Port Injection does not improve performance so there is no reason to run it on the motocrossers,” wrote Editor Mitch Lees. Plenty of racers who’ve been scared off by the electronic tuners, rider aids and map options of the four-bangers lined up at dealers’ doors almost immediately.

KTM’s 250SX is a basic machine compared to the four-strokes but it still copped major changes for 2017 thanks to Kato’s tireless R&D department. We rounded up ADB’s resident two-stroke fan, Wes Mills, and former Australian junior champion Rhys Budd to test it at Oakdale Junior Motocross Track.

“The 250 is a torquey engine. You can ride it a gear higher and use the torque a lot more than you used to be able to on older 250 two-strokes,” explained Wes. “It gives you the option. You can smash the clutch and ride it aggressively or just cruise.

“Overall it was a very safe bike, even though the power was a bit scary because there is so much, it’s pretty tame.” Coming off his 125, Rhys took a while to adjust to the 250 but found his sweet spot eventually.

“For me at first the power was pretty scary. It’s not what I’m used to riding but after a few laps I got comfortable and it was a great bike to ride. The power was there when you wanted it and it was pretty smooth.

“The only thing I would change out of the box is the jetting. It was sluggish off the bottom and up the top it wasn’t really crisp.” This was a minor issue throughout the day and KTM’s on-hand mechanics played around with the needle to make the throttle response crisper.

“After a few laps we came in and raised the clip to drop the needle,” said Wes. “It was still very rich and we could have changed the needle but it was fine. It’s better to be too rich than too lean.”

The 250SX engine features the same counter-balance shaft as the EXC enduro range, which is designed to reduce the vibration that comes with two-strokes. “Its disappearance is incredible, it feels like you’re on a 125 until you get halfway through a corner and realise how much more power you have,” said Wes. “It’s changed so much from having something that rattles your arms off.

“I noticed straight away from kicking it over. I’m used to getting off a 250cc two-stroke and my hands would be tingling, I didn’t have that at all on the KTM. When everything isn’t vibrating it makes the bike feel newer and tighter.”

KTM’s trademark chrome-molybdenum, backbone chassis was appreciated by both test riders. “The frame is nice, it gives you a little flex compared to rigid alloy frames,” said Wes. “The footpegs are a massive improvement. The seat is very firm but it’s all right because the cover is super tacky and grippy. Overall it’s a well finished bike.”

The WP AER 48 is new for 2017 and both Wes and Rhys thought it performed extremely well. “It steered really well,” said Wes. “The front wheel gripped well on the hardpack track we tested on and the overall balance of the bike felt great. Normally you find a 250 won’t turn as well as a 125 but the 250SX is almost as good.

“I had the impression it would be something I would have to learn to ride with but you can use the same riding style as you do with a traditional fork. If no one told you, you wouldn’t know (it was an air fork). The only thing you would notice is how plush and smooth the fork feels. Plus, the option to adjust the spring rate with the little pump is unreal.

“You can ride the air fork at any pace and it works where some traditional forks that are specially set-up for a rider won’t work unless you’re going flat out. I over jumped and landed on the up-ramp of the next jump and it blew through the stroke but that’s to be expect and I was amazed how straight the air fork kept me. Usually you get bucked around after over-jumping but I stayed pretty straight on the KTM.

“The shock handled the track well today. There wasn’t much grip and through the whoops it was doing a great job of getting as much drive to the ground that the tyre would allow. Usually I would get a bit out of shape over slippery whoops but the thing just kept pushing straight.

“If I was to buy the 250SX right now I wouldn’t take it to a suspension guy. It’s good enough for most people and good enough to race.”

Rhys found the fork to be better than the 4CS version on his previous KTMs. “I thought the air fork was much better. It would soak up rough braking pumps a lot better. Even after doing work to the 4CS on my old bike, the stock air fork still feels better.

“It felt light coming into corners, not what I was expecting, and through turns it felt really stable. It soaked up over-jumps well and kept me pretty straight. It didn’t bounce too much. “Going over the rhythm sections the shock wasn’t kicking around and through the stutters it didn’t kick around.”

Both riders found the brakes to be excellent, commenting that the Brembos had nice feel, especially after the pads bedded in. The hydraulic clutch also was popular.

There were minor things that could be changed to make the KTM 250SX perform better but they were all quick fixes. “Any issues I had today with the bike could be easily fixed,” said Wes. “A little bit more time with the jetting would get it perfect and the stock tyres didn’t suit the hardpack.

“They would have been good anywhere else but the blue-groove track needed a hardpack tyre. There still wasn’t much front wheel push but the back was struggling for traction.

“There are going to be a lot of older guys who raced when they were younger but left the sport to do other things are going to take a serious look at two-strokes to get back into riding.”

2017 KTM 250SX Specs

Type Reed-valve, piston-port
Displacement: 249cc
Bore & Stroke: 66.4 x 72mm
Cooling: Liquid
Compression Ratio: N/A
Fuel METERING: Mikuni TMX38
Tank Capacity: 7L
Transmission: Five-speed
Clutch: Wet multi-plate, Brembo hydraulic

Wheelbase: 1485mm
Seat Height: 960mm
Ground Clearance: 375mm
Weight: 95.4kg dry

Front: WP AER 48, 310mm travel
Rear: WP AER monoshock, 300mm travel

Front: Brembo, 260mm wave
Rear: Brembo, 22mm wave

Running Gear
Handlebar: Neken tapered
Front Tyre: Dunlop Geomax 100×90/19
Rear Tyre: Dunlp Geomax 90×90/21

Price & Contacts
BILL $11,495rrp
BLOWER 1800 644 771
WARRANTY Three months parts