2015 KTM 250 XC-F

Introduction

• A do all 250cc four-stroke off-road racer.
• KTM modifies the motocross bike and makes an off-road racer for you.
• Full-race, not detuned. For closed course competition.

KTM’s 250 XC-F is built specifically as an off-road racing machine for closed course such as GNCC, GPs or Hare Scrambles type races. It is based off the SX motocrosser with only the proper modifications that set the bike apart for off-road. And these changes are things that are not the easiest to do if you were trying to convert a motocross bike--specifically the six-speed transmission. But having the larger fuel tank, kickstand, 18-inch rear wheel, suspension set up for off-road racing and handguards (as standard) makes the bike, like KTM likes to brag, “Ready To Race.” From the power producing point, the engine is an SX-F and produces an unrestricted near 14,000 RPM rev celling from the DOHC, four-valve Single. The chassis is identical to the SX-F except for a tap for the kickstand added.

The duty call of the XC-F is so versatile as well. For most skill levels the XC-F is actually a better motocross bike and it sure looks like one aside from when it is parked on the kickstand. By adding a spark-arrestor (and  hopefully a little quieter) muffler it has the legs to go off-road on trail rides. Just the nature of a good strong motor allows the bike to be used anywhere and the suspension setup sides on aggressive so it will work anywhere. Is this the one bike that can do it all?

Changes

• The orange frame and white plastic highlights stand out.
• Engine improvements for better durability.
• Suspension upgrades learned from the SX line.

For 2015 the visual change inspired from the factory race team bikes, specifically the orange frame really brightens up the bike. But they didn't stop there with a lot of updates to the engine and suspension. Both the WP 4CS fork and the WP rear shock have a little more suspension stroke. The new rear linkage provides less progression over the stroke and has the bike sitting lower while the front pinch clamp on the fork now carries a smaller 22mm front axle down from 26mm and moved back 2mm closer to the engine. The frame has a new crossover tube that attaches the linkage to the frame with less welding and more precision on the location.

Inside the engine the biggest change is to a plain bearing on the big end of the crank for claimed longer durability. Small changes to the clutch basket to lighten it up and a new spring for better feel, as well as a different master cylinder round out the major changes. Some O-rings inside the motor were upgraded to enhance durability.

On the outside a new black anodized Neken handlebar, two-piece hand guards with new material, softer compound grips, Giant black colored rims with Dunlop GEOMAX AT81 tires. Even the fork guards are changed to lighten the weight and attach to the new lower clamp.

Power

• One of the longest powerbands in the business.
• Very smooth and progressive build of power that gets stronger with RPM.
• Very light flywheel feel so stalling can be an issue.

While the reason for the 250cc four-stroke engine size is purely to fit into racing class size requirements, KTM is trying to squeeze every ounce of power out of this engine. On a dyno the 250cc 4T KTMs are typically putting out the biggest numbers. Yet on the ground they tend to feel very smooth and quite docile in comparison to the dyno chart, at least the horsepower line. The secret is the long and comparatively flat torque curve the engine produces. With a very light flywheel effect and spot-on mapping on the fuel mixture, the bike is responsive and crisp when warmed up. Starting was never an issue and we never missed the kick-starter one bit.

The power off the bottom is something that you would only find in expensive race-tuned engines with short fuses just a few years back. FI has cleaned up the bottom end and allowed the power to be produced at lower and lower RPMs, and this KTM is no exception. But with very little rotating mass to keep the engine spinning the point of stalling is also more dramatic and sudden should you have the throttle closed. Once building the KTM power curve is smooth, very linear and revs beyond what you’d feel is safe. There are no steps or hits in pure roll-on or twisting of the throttle, just lots of power for a smaller four-stroke. And whatever rev range you need or like to be riding in the XC is as good as you are going to get in power.

So the downfall of KTM’s linear power is that without any steps or changes in the powerband’s delivery characteristic a rider can get lost with such a wide range of useable RPM. And the power coming out of the 250F drops off quite bit in comparison. So a rider will have to practice being aggressive on this engine because it can easily let you get lazy and still work just fine. Think the third hour of a GNCC and here you won't be fighting a hard to ride machine. But don’t think that the XC can't be aggressive too. All it takes is a little clutch work and the bike will pick-up into the high-power zone and then whale along. It revs long and really uses the abundant length of RPM.

The six-speed semi-wide ratio transmission is a perfect companion to the power character. Along with a great hydraulic clutch they make easy work of putting the power to the ground. Standard gearing got us a top speed (GPS indicated) of 98.1 MPH with a decent tail wind at one point. More often we saw 89-90 MPH consistently and sixth gear is a little bit of a step from fifth, which is a good thing for high-speed racing. For tighter racing we'd consider adding a couple teeth to the rear sprocket or dropping the countershaft a tooth which would largely eliminate the use of first gear and use more of third and fourth, not second and third. The clutch pull is light and consistent but you don't need it as much as you'd think. We were really surprised by how well the XC shifted and pulled wide-open clutch-less shifts too. And it will do it till the engine oil needs changing and them you'll feel the need to use more clutch on shifts.

Oh yea, there is no kickstarter. Don't worry, your car hasn't had a crank starter since they put electric starters on them years ago, motorcycles are finally catching on. Don't worry too much about insignificant things. And one other standout point about this 250F was that it was really efficient with its cooling system. Where a lot of other bikes seem at the limit of what the radiators can handle, this KTM barely spit a drop of coolant during testing even when we were hard on the clutch and not moving that fast.

Suspension

• Set up for aggressive off-road, meaning it can motocross just fine.
• The WP 4CS forks have a unique feel and are not typical. But they do work well.
• Having a rear linkage gives the KTM more flexibility in more ways than one.

Suspension seems to be the area that the KTM XC-F line defined. And it has been a struggle from different suspension setups, from linkageless PDS to a few different versions of closed-cartridge forks. Now pulling from the successful improvements made to the SX line, the XC-F takes identical components and has them valved and set up for off-road racing.  And as personal as suspension is and for the wide-ranging intended uses of this bike, KTM has nailed it.

We rode the bike on everything from a jump-filled MX-SX style track to a few very natural outdoor MX tracks. We raced it around on GP-type courses and even took it out on long trail rides. There wasn't anything the suspension could not handle, but it was not really perfect anywhere. Hence the nature of extreme flexibility.

If there is a place where the XC-F seemed most suited, it was a rough motocross track. The bike’s softer setup than a typical motocross bike allowed it to have an added level of comfort while never giving up anything on outright performance. If anything the XC-F got better traction and stayed planted on the ground where a stiffer motocross bike would get kicked and deflect. There were some setup changes that really helped this out too.

The WP 4CS forks are still a newer system and they do not quite have the same feel as more conventional cartridge forks and certainly they don't act like current air forks. Initially they have more stiction than we'd like--a feeling that transmits the some of the sharp impacts to the rider whenever the front wheel hits something.  Some like this feeling as you get a sensation of the ground, for others it is uncomfortable. And it is more noticeable on hard ground. Aside from that the action of the fork is stiff for an offroad bike and it holds the balance with the similarly set-up rear end. The single side adjustment atop each fork leg does not act conventional either. Both compression and rebound adjustments work more on the mid-speed damping force on the fork and not on the typical low speed damping. It takes a good 3-5 clicks to get the fork to act stiffer or softer where you would typically feel the change. In used the adjustment seemed to adjust the ride height of the front end as much if not more than the damping. Very similar to the changes a high-speed adjustment on the rear shock makes to the way the bike rides.

All-in-all the fork is has a very consistent stroke and good progression, just stiff feeling all the time. The bottoming control is great for a spring fork.  Allowing some oil to wet the seals really helps the comfort and making sure there is no air built up in the fork is critical. We even compressed the fork slightly and released air to create a negative pressure inside the 4CS and it reduced the initial stiffness/stiction, especially in technical off-road.

The rear shock is very typical WP and rides through the linkage setup, revised for 2015 on lessons learned on the SX models. The shock matches the performance of the fork but the adjustments are much more familiar. One to two clicks make a noticeable change. Like all bikes setting the sag is critical and on this bike knowing your setting to match the way you like a bike to handle will pay dividends. The true advantage of the linkage is allowing the shock additional stroke and isolating its mounting off the major stiff frame and swingarm components for a better feel. You can have this stiff setup without the bike feeling like a steel plate.

Even with heavier riders we were running pretty stock setting on the motocross tracks. In our opinion riders lighter than 165 pounds might even be looking at softer springs. Off-road we had both compression and rebound on the fork clicked out 3-5 clicks softer and used a matching softer setting on the shock with an additional 1/2 –turn less high-speed compression than standard. This was just to the point where the bike got more comfortable without getting to soft or spongy. How the linkage KTM works in comparison to the PDS system seems to be a common question and we can offer this information. Initially learning and finding a good setting for a picky rider on the linkage bike will take longer and be more work, but once you have the setting adjusting it is pretty straightforward and not needed as much. With the PDS getting an initial setup is simple but you’ll also have to change it more to keep it working properly.

Chassis - Handling

• A very neutral handling bike that can be set up for almost any rider.
• Roomy with a wide-ranging ergonomic package.
• light like a two-stroke, planted like a four stroke, stable all the time.

KTM has nailed the ergonomics package to a point there is nothing to complain about, even the seat is so much better than in the past, they are setting an ergonomics standard other bikes will be compared to. With handlebar adjustability through the top clamp allows four positions and overall the chassis is roomy, thin and with nothing to hamper the rider in doing what needs to be done. Even while packing a bigger gas tank.

Working on the bike is plain and simple for the basic maintenance and durability from all accounts and our experience has been great for a 250F, if not any size of machine. The attention to detail has a very high level and that carries over to the characteristics of how the XC-F handles.

Like all 250Fs the KTM has a very light feeling but not the twitchy or jumpy light feeling of a two-stroke. It has a planted feel at the same time. Since the rotational mass in the engine is less, the bike does not gain weight when the revs go up so it stays light and flickable all the time. With a scale weight of 247 pounds, full of fuel, (about 15-pounds lighter when empty) the XC-F weights the same as a typical 450cc MX bike, but you'd never feel that without checking the scale.

The XC can handle almost any way you’d like it to with just some simple and basic changes to the ride height of the bike. Very neutral with a standard 100-105 mm sag setting, you can get the bike to be a front-steering bike by going a little tighter on the rear spring or by adding some high-speed compression. Conversely you can drop the rear a little and then the bike will slide and track off the rear wheel like a champ. Yes, light 250Fs always seem to handle excellent but this one is special. Where the KTM really shines is that the stability stays excellent as long as you are in the ballpark, it isn't finicky like a lot of other bikes. It has a little bit of a long bike feeling when it needs to.

So when you really push the bike the confidence stays high--when getting bounced it tracks straight. It is easy to put the weight on the rear end and drive forward. In tight and technical riding the bike likes to have the front lifted over the stuff that will depict the stiffer front fork, but that is easy to do with such a long powerband, then the rear will track across the bumps clean. In really technical stuff the long and smooth power matches with the easy to ride chassis. This makes for a bike that is so confident on the track work like no motocross bike could off-road.

The brakes are the standard most dirt bikes are judged by, especially in a light 250F. Though some MX bikes are going to oversized rotors, the KTM has the same amount of power and a higher level of feel on the front. The rear brake can be a little on the touchy side for some. Again it is strong with decent feel. Bonus for the ease of adjustment on the front brake lever as well as the hydraulic clutch.

If we get picky we'll say that the Dunlop AT81 is a good all-around tire but it did not like the transition onto harder surfaces, mostly the rear. The handguards are a bit on the fragile side and discolor easily when getting used. KTM makes nice skidplates, and save yourself an expensive mistake and put one on this bike, we think it should be standard. The XC-Fs kickstand is a great touch for off-road and you hardly know it is there unless you need it. With 2.4-gallons of gas which can get almost 70-miles on a trial ride if you are conservative and at the same time guzzle that gas in an hour at a race pace. And there are plenty of tank options out there should you need more (or less).

Conclusion

• The answer: this one race bike does it all.
• Built tough and just how it should be equipped.
• Setting the bar for a popular market segment in the US and elsewhere.

The KTM XC line is purpose built for the typical American rider. A guy who wants to do all kinds of riding but want to do it on one bike. A bike that he or she does not have to make any excuses for in terms of performance or perception. Yes, that means a rider who wants the best and most exciting bike they can get their hands on. Most of the time that was the motocross bike, since it was perceived as the top of the line even if there were tons of downfalls with a specific (excessive, usually) performance criteria. KTM has taken that formula and high-end parts to make a bike tuned to do as many different types of riding as possible. Doing the tough modifications for you KTM has defined a class of bike other manufacturers are looking at very clearly. The 250F category is the stepping stone into the big bike world for younger riders and for smaller or lighter riders a size that fits them nicely. There is nothing like a light bike that is truly fast, this KTM fits that criteria.

Looking across the KTM line one might ask whether the XC is right for you. The XC-W does not like the track. The SX does not like the trail (or much else than the track, really). The XC-F bridges that gap with a setup that will work everywhere and for anything in between, like GP style events, where a mix of motocross and off-road is common. Here the XC is the right choice. But the whole time we are constantly reminded how well the XC-F works on the motocross track. For all but really fast intermediates and faster, it is likely a better choice.

Then you might want to know how the KTM 250 XC-F compares to the other bikes like it, mainly the Husky (very similar in many ways) and the all-new Yamaha YZ250FX. Well we did a lot of testing in conjunction with the Yamaha which we'll post about later. Just like flavors of ice cream or colors of the rainbow, they are personal choices, not better or worse.

If you can handle a stiffer riding off-road bike the XC-F will make you happy in every way you can expect out of a 250cc four-stroke. At $8599.00 bikes at this level are not cheap but you are getting performance that is pretty impressive.