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Friday, January 7, 2011

ktm dirt bikes 2011 colections

There really is no doubt that the KTM 350 XC-F and its sibling, the 350 SX-F, are the hottest news in the dirt bike world this year. I got my first look at the motocross bikes earlier this year at the USGP where Mike Alessi and Tony Cairoli made impressive debuts. Now, the XC-F off-road version quietly arrives just as the year comes to a close.

The concept of building the ultimate mid-size bike is not a new one. In fact it is almost a staple of the motorcycle industry to bring the concept back around every decade or so. The goal of course is to take the handling of a small bike and mate it to an engine that performs like an open-class bike. Perhaps the most successful example would be the Honda XR400 that went on to have a very successful career.

The real difference here is that current generation 350’s were designed from the ground up as new technology bikes. Nothing borrowed and everything new. It is probably more correct in this case to say that the 250 and 450 were designed around the 350. So will it really bring us the best of both worlds or will it be another victim of too many compromises?

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The rumor mill had been talking about the XC-F versions for a while and everyone seemed convinced that they would feature a PDS shock. As it turns out this is only for the EXC versions which won’t come to the States. For the U.S. market these bikes are just lightly reworked versions of the motocross models. That means they get the latest KTM reinvention: linkage.

Essentially the chassis for all new KTM SX-F and XC-F models is the same. The engine cradle for the 450 is slightly different but everything else front to back is identical. Up front the 48mm WP closed chamber forks receive the same valving updates as the rest of the line and get specific off-road settings. The .48 N/m is the same as the SX-F model. The KTM linkage is quite an eyeful for the orange bike lovers. The shock is long and the linkage hangs quite low. The WP shock has the full range of clickers and uses a .54 N/m spring - again the same as the moto version.

ktm dirt bikesktm dirt bikes sx off road

The XC-F conversion to cross country race bike is minimal. The fuel tank capacity is up to 2.5 gallons (from 2.0). The 19” rear wheel is replaced by an 18” that runs a 110 series tire. A kickstand and moto style handguards finish off the list of off-road specific parts. The XC-F models are not intended to run lights and have no other amenities such as spark arrestor or odometer.

Like the chassis, the fuel injected engine is nearly identical to the SX-F model. The entire top end, including the cam and piston, are the same. Ignition mapping is unique to this bike and features a standard map plus two optional settings. These require the KTM hard equipment accessory switch to change maps. The 42mm Keihin EFI throttle body is the same for all the 250/350 line up.

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Also new is the addition of a kickstarter to back up the electric starter. KTM claims the racers wanted this feature for dead engine start races. It is nice to have the security of the backup starting. Also new is the transmission with an added cog and all new ratios for the off-road model. As you can see in the graphic, the ratio changes are pretty significant and give the XC-F much longer legs.

Gear 350 SX-F 350 XC-F
1 14:30 15:31
2 15:24 16:25
3 18:24 20:25
4 21:24 22:23
5 22:21 25:22
6 26:20

During the official new bike presentation KTM made it pretty clear that this bike is designed to win the GNCC title. That is where much of the company’s off-road race resources will go this year. I have also talked to a number of the orange team riders and it seems that nearly every one of them wants to race the new 350 next year.

So it looks like it’s a hit with the pro level riders, but what about for the rest of us? KTM has almost gone out of their way to keep any enduro type amenities off of these models. Based on the spec sheet this looks to be pretty much just a motocrosser with a wide ratio transmission.

Everyone’s first question when seeing this bike is about the motor. What is it like? Well, the short answer is that it feels much closer to a 450 than a 250. Probably 50% of the time it feels like it does everything on par with the larger bikes. My first ride was on the vet motocross track and the engine was an absolute
The addition of another cog in the transmission gives the XC-F wider gear ratios that the SX-F.
The addition of another cog in the transmission gives the XC-F wider gear ratios that the SX-F.

The great thing about this bike on the track is it almost always seems “just right.” For coming out of a corner, just turn the throttle wide open. Gear selection is optional, for most situations it will let you run in a tall gear or a low gear. Carry a tall gear through the corner, feather the clutch just a little on exit and save two shifts in the process. It does not require the all-out commitment of riding a 250F. It may be just the perfect engine for the average track rider.

Once off-road it shows a little more of a split personality. At slow trail speeds it will plunk along perfectly happy. The EFI response is crisp and it’s happy to trail ride at any speed. I expected it to be too aggressive for this type of riding, but not so. It’s almost like riding a 300 two-stroke with a nice, gentle personality.

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