2013 KTM SXF Range Ridden & Reviewed
By Mark Willis
KTM has gone all out for their 2013 SXF range of motocross machines, with the 250 SX-F, 350 SX-F and 450 SXF all getting an overhaul. The 250 SXF and 450 SXF receive the majority of improvements with the 350 SX-F going on a diet and receiving some more horse power
There is no doubting KTM’s commitment to the motocross scene, with the signing of Ryan Dungey late last year to spearhead the all-new 450 SXF in the AMA Supercross and Motocross series. The results so far this season have proven they are on the right track with Dungey picking up multiple Supercross wins. He is currently on the verge of taking KTM’s first ever open class championship win in the AMA Motocross series where he is the series leader. Over in Europe, Antonio Cairoli continues to crush the competition aboard the KTM 350 SX-F.
For 2013 KTM have focused intensely on the handling of their bikes and the chassis has come in for a major revamp. The swing arm is cast aluminium and has been reinforced in the rear arms with a 25mm rear axle, up from 20 mm in previous models, offering improved stability. While all the Japanese manufacturers have opted for aluminium frames KTM has stuck to its chrome –alloy-steel for its mix of stiffness and flexibility. The new model 4-stroke frames receive additional reinforcement in the steering head for higher torsional stiffness while thinner profile tubes around the engine offer a saving in weight. There have also been further improvements to the CNC machined triple clamps to aid greater stability with a focus on the fork clamping to reduce friction in the front suspension.
Suspension is again supplied by WP with 48mm closed cartridge forks and reworked settings in the shock. The 250 SXF and 450 SXF receive heavier front springs while the 350 SXF receives the same modification in the rear. Adjustments are good with high/low speed compression and rebound on the rear and easy adjustable compression and rebound on the forks.
The fuel injection system has been radically reworked for the new MY2013 four stroke range with Keihin supplying a new EMS with an increased throttle body size up from 42mm to 44mm. It also has improved injector and injector position (spraying upwards) instead of down which is integral to power gains across the three models.
Another feature across the board on the new generation SX-F engines in is introduction of a new connecting rod (supplied by Pankl) which features a pressure lubricated plain bearing on the big end which allows for higher rpm as well as increased (i.e. doubled) service life.
— 2013 KTM 450 SX-F
Along with the above mentioned chassis updates, the 450 SXF has a completely new engine. The previous model KTM 450 SX-F was a beast of a machine to ride, with no shortage of horsepower but incredibly hard to put it to the ground, so I was super keen to see how they have changed and how much better the new 450 is.
The new engine is based on the latest generation 450EXC engine and is a SOHC with newly designed ports, combustion chamber and valve train. It has lightweight titanium valves which allow for an increase in rpm limit to 11,500 and HP figures of 60+! The crankcases are now die-cast instead of sand cast, allowing a thinner wall thickness and a saving of 2.5kg over the previous model.
Power is delivered through a newly designed, four- speed transmission and this engine receives the DDS clutch system that has worked so well in the EXC engine. It is electric start only.
I guess the first thing that I noticed when I rode out onto the track on the new 450 SX-F is its ergonomics. The bike – although a 450 – feels nice and slim, not big and bulky like some of its competitors. After a brief dart back in to the waiting mechanics to adjust lever positions, it was time to see if the machine lived up to the hype! The first thing I noticed was how smooth and balanced the engine felt. On the track I was able to let the 450 lug around in 3rd gear everywhere and it was just so smooth. It produced a nice even and very controllable spread of power and although it accelerated it was not trying to tear you off the back of the bike.
I was impressed with the gearbox and clutch with the bike shifting between gears effortlessly while the super light feel from the hydraulic clutch allowed me to get out of a couple of the tight corners in third gear. I also did a race start on all bikes and connection between throttle and clutch was sensational. The bike tracked well under brakes with the Brembo brakes offering good feel and initial bite and the suspension absorbing what little braking bumps I could find. The suspension felt good, but there wasn’t much for it to do on this track. It absorbed the jumps without issue and makes the bike feel quite light and easy to manoeuvre for a 450. It would have been nice to be on a track that allowed the 450 to stretch it legs a bit more and maybe with some bigger bumps, but first impressions on this track were great. It is a very rideable bike and will suit a far greater demographic than the previous model.
If you want to adjust the ignition or fuelling on these bikes, there are a couple of options that are available as an option from KTM stores. A map switch that has three maps inbuilt or you can buy the tool that allows you to customize within parameters but you need a laptop to do this.
- Pros – KTM 450 SX-F
Smooth and tractable H.P
Easy adjustable suspension
- Cons – KTM 450 SX-F
Little flat up top
Four speed gearbox. (Wasn’t a problem at this track but potentially may be an issue)
Would be nice to have the map mode switch as a standard feature
CONCLUSION – The new KTM 450 SX-F is an amazing step forward for KTM. I won’t be surprised to see plenty of these sold over the coming months as it’s a model that has been languishing for some time in their range. The build quality is great, good components, great user-friendly engine, and a well handling bike straight out of the crate.
— 2013 KTM 350 SX-F
The obvious focus for KTM with the new 2013 KTM 350 SX-F is in the engine room. Although the new bike gets the same upgrades in the chassis department as its siblings, KTM have gone about increasing HP and shaving some weight from the already impressive 350 SX-F engine. This bike was an absolute favourite of mine when it was released two years ago so I am interested to see how they go about making a great bike even better.
The engine has had a range of improvements including a reworked cylinder head, new intake and exhaust ports, stronger intake valve springs and an increase in the rpm limit to 13,400. The engine cases are also die-cast like the 450 SX-F and the removal of the kick start casting have helped to reduce the overall weight of the engine. It also has a new piston and improved water jacket design in the cylinder to help keep things cool. The 350 SX-F also has updated exhaust with new hydro formed sections with HRS (Header Resonator System) that improves HP while reducing noise.
Out on the track, I rekindle my love affair with this bike. It really is the best of both worlds. You get the lightness and ease of ride that you expect from a 250 and the bonus of having some grunt and HP like a 450!
The power delivery is very smooth and once you realise you can leave this bike in a higher gear and use the torque of the engine, it is so easy to ride. The biggest difference to the 450 is just how early in the corner you can crack the throttle. Most bikes feel better once suspension is loaded and the 350 SX-F allows you to get on the gas incredibly early. The added HP and torque is nice, although it’s been nearly two years since I last rode the 350 SX-F so it’s hard for me to compare to the last generation of 350 SXF engine.
The chassis package is sensational and this bike is so easy to stop. It has barely any engine breaking and you don’t get that propulsive feel that the bigger pistons seem to give, pushing you deeper into the corner. The 350 SX-F tracks so well under braking allowing for precise turn in and corner exit set up. The bike is light and very easy to throw around and you can basically change line by looking at where you want to be on the track! Brembos have no problem in slowing your momentum and the suspension worked a treat.
A race start was similar to the 450 with the connection from throttle to clutch just magic. If I had to be picky, about the only thing I would change would be maybe adjust the fuelling a little bit right off the bottom. The connection from off the throttle to on was a little bit crisp for my liking. We did make it a little better by repositioning the throttle.
- Pros – KTM 350 SX-F
Too many to list
- Cons – KTM 350 SX-F
Like the 450, it would be nice to have the map mode switch as a standard feature
Conclusion – I still love this bike. It is a great handling bike that is easy to ride. It’s got enough mumbo to put a smile on your face without making you look like a swapper!
— KTM 250SXF
The 250 SX-F has received a radically improved power plant for the 2013 model. The figures speak for themselves with KTM claiming a staggering 5 HP more with this new engine. That alone is exciting, as anyone racing in the Pro-Lites class would understand the costs associated with increasing HP to that level!
Just about all of the major components in the engine are new. It features a new cylinder design with a 2mm diameter larger piston, new Pankl crankshaft with a shorter stroke, newly designed head, die-cast cases, and the list goes on. It has a standard rev limiter set a staggering 14,000 rpm!
It has a new six-speed gearbox and is fitted with the same proven clutch that is in the 350 SX-F featuring a lightweight one piece CNC machined steel basket. Brembo once again take care of the hydraulic activation of the clutch and also the brakes.
It receives the same suspension and chassis updates as the 350 SX-F and 450 SX-F and out on track it is easy to see the improvements.
The engine is incredible for a 250. In a lot of situations in order to gain an increase in top end or outright HP you will have to take it from somewhere else in the power range. This is not true with the new 250 SX-F. It still has the nice low-to-midrange power from the previous model and then just keeps on producing power right through to the limiter. The gearbox is precise and the clutch feels great.
The suspension does a great job and while it doesn’t feel quite as planted on the track as its bigger brothers, it does feel nimble and agile. Like the 350 SX-F it was a little bit crisp from off the throttle to on but that might be me just being a little bit picky! It turned really well and was as comfortable in ruts as it was on flat corners, offering confidence inspiring front end feel.
- Pros – KTM 250 SX-F
Super powerful 250 four stroke engine
Turn in and mid corner stability
- Cons – KTM 250 SX-F
Fuelling from no throttle to opening of throttle
Conclusion – The 250 SX-F is a power pack to be reckoned with in the quarter-litre class. It has a great engine and chassis and is nimble and easy to ride. The improvements to the engine in regards to service intervals should be great for the consumer’s pocket.
— Pictorial – High-Res Image Gallery featuring the 2013 KTM SX-F machines