2015 KTM 250 SX-F


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2015 KTM FACTORY EDITION 250 SX-F AND 450 SX-F UNVEILED

KTM invited the media out on Thursday to unveil their 2015 Factory Edition motorcycle and to introduce the supercross race teams. The evening got very interesting when not one, but two covered bikes awaited the announcement – KTM then unveiled two Factory Editions – a 250 SX-F and a 450 SX-F (this is the first year for a 250 SX-F Factory Edition). Then things got even more interesting than two covered bikes rather than one when the list of changes started getting explained – these bikes are radically different from the ‘standard’ SX-Fs and look like a jump ahead in several model years. The short version is that these bikes are practically all new, and the focus was on weight savings. Dirt Rider hasn’t received either bike yet, so all information was provided by KTM – but the bikes look great and all the KTM employees looked extremely proud. Jon-Erik Burleson, President of KTM North America, said when introducing the bikes and discussing the Factory Edition models, “The coolest part about this new Factory Edition bike is it really represents – I think in all of our opinion – this is really the first true Factory Edition that Roger and Ian asked for when they first came to KTM. This thing is revolutionary. ” Then the KTM crew hit on some of the highlights of the new bikes, in addition to handing out technical specs.

The big news – these bikes are light! The 450 dropped 10.3 pounds and the 250 dropped 6.9. That puts the 450’s claimed weight at 226.2 pounds and the 250F’s claimed weight at 221.6 pounds.

The engines on both bikes are all-new, inside and out.

250 – The clutch has been raised 26.9mm and moved back 11.1mm, the crank is moved up 6mm and the connection rod is 6mm shorter. The motor is two and a half pounds lighter than the standard 2015 250SX-F motor, and is 20mm shorter overall. (The photo below shows the new and old engine cases together for comparison).

450 – The motor is also entirely new and has three more horsepower. It is four pounds lighter than the 2015 450 SX-F motor. The motor’s external size is shortened by 23mm, lowered by 9mm, and narrowed by 23mm. Internally, the crankshaft up 7mm and back 9mm and the clutch shaft is up about 20mm and back, and the cylinder is shortened 6mm.

Here’s something interesting – In the 250’s transmission, second, third and fourth gear have a new treatment aimed at increasing durability, and in the 450 it’s first and fifth gear that get a new treatment. Both bikes get a new coating on the shift forks and the 450 gets a “reworked” shift drum.

Both bikes have redesigned clutches. The 250 has a CSS (coil spring steel) clutch that has 7 plates now instead of 8. The 450’s DDS (damped diaphragm steel) clutch gets a new basket. Both are designed to better flow oil to keep the clutch and therefore the motor cooler.

The R&D team didn’t want to increase the size of the radiators (keeping with the weight savings goal), so they improved the airflow with new grills (which are protectors, too) and a new exit route (check out the tank/shroud to see the new exit channel for hot air. This is claimed to help cooling by about ten percent.

The new battery weighs 1.1 pound. It’s the first time KTM has spec’d a lithium ion battery on a bike. Yes, in the weight reduction program KTM kept the electric start.

The exhaust is new on both bikes, but different. Both machines have a different head pipe and their muffler is now 40mm shorter. The new exhaust moves the muffler a total of 60mm closer to the center of mass (forward). With internal muffler changes, the new muffler is also said to be quieter.

450 – the bulged 450 head pipe is called a Flow Design Header (FDH), and it looks wild. It basically looks like a small two-stroke expansion chamber, and is designed to improve power and throttle response while helping reduce sound.

450 – The rubber seals on the 450’s crankshaft are replaced with metal shims that provide a better sealing surface and allow the engine to be narrower.

Both bikes use a new 44mm Keihin fuel injection system; yes, both bikes use the same 44mm throttle body. The new throttle body does not have a linkage, which KTM says is now more ‘direct controlled from the operator,’ they have new throttle cables with the adjusters up at the throttle housing (up at the handlebar). Below, the Factory Edition throttle body is on the left, the standard body (with a linkage) is on the right.

Both machines have engine mapping switches on the handlebar. They also both have an integrated launch control. These work together with the engine map and the gear sensor (so it knows what gear you are in). The launch control had a different max rpm for each engine map you are running for the track – and that rpm max is different for each gear. The engine mapping is also gear-specific for each map.

The cam chain and guides are all new to decrease drag and weight.

The frame on each bike is all new. The new head stay mount positions (on the sides) are told to help with handling and to reduce vibration. The new frames have 20% more torsional rigidity (twist) and 30% less longitudinal stiffness (to help with impact absorption). The frames are also designed to better isolate the shock so it can work better. Below, the new Factory Edition frame is in gray, the standard SX-F frame is in orange.

The new rear shock linkage curve is similar to the ‘standard’ 2015 linkage but gives the rear suspension 10mm more travel and also, because the leverage ratio is what KTM calls “optimized,” the bikes can now run with lighter shock springs (from a 5.7 to a 4.8 on the 450) and run 5mm less preload. The new chassis/swingarm/linkage combo is claimed to make the shock spring rate and shock valving set up less critical than on past KTMs. That is to say, the new system should work better over a wider range of riding styles, rider weight, and type of riding compared to the previous design. (Below is a cutaway of the FE’s new swingarm)

The new chassis allows the 4CS fork to come set up with more progression to the valving and is said to have more comfort.

Both bikes get a new rubber mount system for the handlebar, and the lower triple clamp is designed with more flex as well. There are two mounting positions for the handlebar clamps.

Compared to the standard SX-Fs, the seat above the pegs is 10mm lower, the back of the seat is 20mm lower and the handlebar is 10mm lower. All of this with what looks like a good amount of padding on the seat, even at the back. The design goal was a flatter and more compact rider cockpit, and a more natural riding position.

The footpegs are lowered and moved back. They are a new cleat design (larger than the previous peg) and their pivot is engineered to scrape away any mud that could clog up the peg’s movement.

The brake pedal and shift lever are new, and look very light. The shifter’s tip is designed to prevent mud from getting into the pivot. That shift tip is a rounded square shape; the engineers spent three weeks on designing just that component. The KTM crew used this as a good example of how everything on the bike has been considered and improved where possible – with their weight reduction goal front and center.

The bodywork is all new. The side is designed to be very flat to allow the rider to better grip the bike. The side panels are now removable, not part of the subframe. And the tank/shroud is designed with a large air exit channel for better airflow through the radiators.

The new bikes have a new airbox cover. It’s still a ‘no tools’ filter replacement system, but now it lines up and locks in better. The air boot/intake velocity stack got a lot of attention (and a new material) and while it was getting tuned it also gained stiffness and lost nearly a pound of weight.

The 450’s retail price is $10,199, and the 250F’s price is $9,299.

MXA’S 2015 KTM 250SXF VIDEO

SPECIFICATIONS
Year 2015
Manufacturer KTM
Model 250 SX-F
Engine Type Single-cylinder, four-stroke
Engine Displacement 249.91cc
Bore Stroke 78 mm x 52.3 mm
Cooling Liquid-Cooled
Compression Ratio NA
Fuel System Electronic fuel injection
Ignition Contactless, controlled, electric ignition system w/digital ignition timing adjustment
Starting System Electric starter
Transmission Six-speed, claw shifted
Final Drive 520 X-ring Chain
Rake Trail NA
Seat Height 39 in.
Wheelbase 58.8 in.
Front Suspension WP Suspension Up Side Down 4860 MXMA 4CS 300 mm
Rear Suspension WP Suspension 5018 BAVP DCC 317 mm
Front Brake Disc brakes, brake calipers on floating bearings 260 mm
Rear Brake Disc brakes, brake calipers on floating bearings 220 mm
Front Tire Dunlop Geomax MX 52
Rear Tire Dunlop Geomax MX 52
Fuel Capacity 1.98 gal.
Dry Weight 225.3 lbs.

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