The KTM 400 helps Sean Finley...
The KTM 400 helps Sean Finley get out of the office...waaaaaay out.
I have just over 60 hours on our 2009 KTM 400 XC-W now so I figured it was about time to share what I have learned about this bike and make a few suggests for modifications in case you are lucky enough to own one yourself. First off, the XC-W is a very versatile bike. I have competed in a couple of enduros and even took it to the motocross track, but mostly I have just used the bike for a wide range of trail riding.
KTM only makes the 400cc size in XC-W form (W for Wide ratio transmission and the W models also comes equipped with a kick start). I have had the opportunity to ride the 450 XC-W as well as the 450 XC for comparison. The 400 has a more user friendly power delivery that many people feel allows them to actually go faster in technical terrain. I tend to agree but on the flip side, I do like the extra burst that the 450 provides. For my taste, I favor the 450, but have had plenty of fun on the 400. For serious trail riding, especially anything with open terrain, the W model bikes are a better choice and provide the backup of a kick start (which the XC models drop in favor of about 10 pounds of weight savings). However, if you are into racing at all, I would suggest the XC model (which means the 400 is not an option) because the tighter ratio transmission is nice and the ten pounds saved is even more noticeable. I have never used the kick start on the trusty KTM, so I am not too worried about needing that as a backup.
It's not as light and feathery...
It's not as light and feathery as similar 450 XC models, but the KTM 400 XC-W still slips through the skinny sections with ease.
As for durability, the motor continues to purr like a kitten and starts very easily. My only service has been four oil changes with Maxima Maxum-4 10W40 www.maximausa.com (both in the transmission and engine, which are separate on the W models). I felt that it must be time to at least check the valves but Karel Kramer, our resident KTM guru, said that if the valves tighten up, it will become hard to start, which has not been the case at all. So I will keep riding it for awhile. Basically, I really haven't done a thing to it. Not even replaced the clutch plates!
The suspension has also held up very well and is surely due for an oil service but the performance is still extremely good for trail riding. When I took the bike to the Cahuilla Creek Motocross track (pretty old school MX with only a few jumps), the suspension was tolerable, but this is where the slightly stiffer XC model with a little less weight and tighter ratio transmission really shows its difference. But like I said, the 400 XC-W was good enough to have a great time at the track.
Top quality and solid performance...
Top quality and solid performance sum up the KTM Akrapovic systems.
Modifications
The single most important modification you can make to the 400 is to change the front sprocket to a 12-tooth. The stock (13-52) gearing is way too tall for trail riding and with the wide ratio transmission the bike still has plenty of top end even with the 12 installed. You can get sprockets from several sources but I got the Pro Taper 12-tooth from Rocky Mountain MC when I was ordering some other parts, www.rockymountainmc.com.
I have found that all of the KTM's have a bit of a lean feeling, especially on deceleration that can be a little irritating. R&D Racing (www.r1dean.com) makes an adjustable leak jet fuel pump cover that completely solves this. The stock FCR carbs that KTM installs do not include a leak jet and this fuel pump cover comes with the parts necessary to install a leak jet while providing external adjustability. I suggest this as a worthwhile modification for any KTM XC or XCW four-stroke. Even though it has adjustability, just installing the leak jet circuit and using the suggested setting has made this bike run great it all conditions.
The stock KTM Exhaust is a decent system but as I noted above, I was looking for something to give the 400 a little extra snap. I was using the FMF Q slip on (www.fmfracing.com) for a while to make the bike a little quieter than stock. Then I installed an Akrapovic full exhaust system. It is significantly lighter than the stock unit but remains extremely quiet, which should be very important to any of us riding on the trails. In spite of the docile sound, the system did provide a little extra power throughout the power curve. While the Akrapovic systems are not cheap, you will have a hard time finding a better quality exhaust. Unless you follow racing closely, you may not realize that Akrapovic is the choice of the KTM Motocross and Off-Road race teams in Europe so they certainly have experience with KTM. You can learn more at www.akrapovic.com.
Finally, I have gone through a few sets of tires on the KTM 400 XC-W and found Maxxis Maxxcross front and rear tires have worked well on a wide range of terrain and hold up incredibly well. More information is available at www.maxxis.com.
 Sean Finley has been using...  Sean Finley has been using Maxxis tires since last October on the 400. |  With minimal time you can...  With minimal time you can improve throttle response and performance on most KTM off-road models by installing carb mods such as the R&D racing adjustable leak jet accelerator pump cover. | |
Do you want more info about the KTM 400 XC-W? Check out these stories elsewhere on Dirt Rider.com.
First Ride impression
KTM 400 XC-W versus KTM 200 XC-W
 Defining the phrase "off-road...  Defining the phrase "off-road workhorse" our KTM 400 XC-W is living the high life with a constant diet of scenic off-road. |  If you want to increase the...  If you want to increase the versatility and usability of your KTM 400 XC-W, change the front sprocket from a 13 to a 12 as soon as you can. |  The slippery stuff and technical...  The slippery stuff and technical hill climbs of Moab were no match for Finley and his ultra-smooth KTM. |
 Wow, seems like we were riding...  Wow, seems like we were riding in this yesterday. Time flies when you're having fun. |  The smoothest power delivery...  The smoothest power delivery of any big(ish)-bore off road four stroke dirt bike makes tight trails a breeze. | |