KTM 350SXF long term report

Back in August of 2011 I wrote an article entitled “KTM 350SXF could this be the ultimate MX/Trail bike?”  Well three years later I have some answers.

Yes I still have the bike some one hundred sixty plus hours later. I can tell you one thing it was not for me, and that’s a motocross bike. The handling was not the issue the way I ride and the power was. I’m a bigger guy at 210 plus gear and it just didn’t have enough power down low to mid range for me. The bike needs to be ridden more aggressively like a 250 in order to get 450 like power out of it in those high RPM ranges, I’m more of a torque it around rider. 

But as a trail bike, cross country race and enduro bike it has been nothing short of great. I usually only keep a bike a year or so, but I haven’t gotten tired of this bike and quite frankly haven’t ridden anything else that would make me want to sell it. Because of KTM’s new generation frame the 350 feels very light and nimble, the four stroke motor has little fly wheel effect so when you back off the throttle for a corner the motor doesn’t push you into the corner, but it still has more engine braking than a two stroke. And like most four strokes it feels very planted especially in the rocks and going up hills.

I bought the SXF over the XCF model because of price, the XCF was just being introduced at the time so there weren’t any deals or used ones around. SXF’s were and still maybe easier to find, have less hours on them and cheaper to buy. And for the type of riding I do the five speed close ratio transmission works very well, you have a motor that rev’s to the moon so you’ll have more than enough top end in short bursts unless you need to run it wide open in the desert.

I’ll recap the things I did to it initially in 2011.

Rekluse Core EXP (I found for me the bike was extremely hard to ride in real tight terrain where you needed to use the clutch a lot)

Enduro Engineering Tall soft seat (I’ve actually gone back and forth between the tall seat and the stock seat I’m currently back on the tall seat)

Factory Connection Suspension (Expensive but a great investment)

Scotts Steering Damper (Pretty much a must for a KTM)

Rear brake rotor guard

Works Connection (Rubber dampened) skid plate

IMS 3.1 gal gas tank (Today I would purchase an Acerbis, much easier to install)

Pro Moto Billet kick stand.

And after having the option of trying out two different brand exhaust systems Dr. D and Leo Vince (Headers and mufflers) I settled on the stock set up, with a Pro Moto billet spark arrestor end cap, it was quieter and I couldn’t feel much difference in power.

Since 2011, I’ve installed a set of Air Cells, (They help soften the initial few inches of travel and work especially well in real tight technical sections). A KTM odometer /Speed odometer and I am still using the original 19” rear wheel. I came up with a hand operated rear brake by using another hydraulic clutch and with time found the right position for all this to fit and work; I still have the foot operated brake as well. I have a couple of friends who have hand operated rear brakes only and swear once they learned to use it can go faster especially in the tight stuff. Personally I don’t want to give up the security of the foot operated brake. I also didn’t give up my clutch either even though I have the Rekluse. There are many times when the ability to use a clutch comes in handy. Rekluse now sells a kit that will allow you to keep the clutch and have a hand operated rear brake as well.

Another thing I’ve experimented with is a set of Fast Way foot pegs the kind you can install in a back and down position.  I’m over six foot tall and for me they made a huge difference, it puts me back and more centered on the bike especially when I stand up. It also makes it easier for my size thirteen boot to shift the bike. When sitting it makes me feel more like I’m sitting in the bike as opposed to sitting on top of the bike especially when using the tall seat. And the ability to stand up is much easier no real effort. I’m not sure this set up would work at all for shorter riders and riders who stand up and like riding over the front end of the bike. The other concern was because of the lowered position would they hit rocks etc, for me the answer has been no.

My bike has always smoked on cold start up and has always used a little oil but after one hundred fifty hours I thought it was time to look at the motor besides I had decided I wanted to make a 400 out of it. After researching kits I decided to go with the Thumper Racing 390 kit. It was a simple exchange of cylinders.  The kit came with a piston, rings and gaskets. For an extra forty dollars they changed the mapping to match the new power output. One of the things I liked about the Thumper Racing kit was the cylinder was bored and coated which means better heat transfer and dissipation that you wouldn’t get with a steel sleeve.

I was curious when the motor was torn down what condition it would be in. I’ve used non synthetic Rotella oil since I installed the Rekluse (Rotella is designed for diesel motors is good, inexpensive, making frequent oil changes more affordable) The motor was in excellent condition, it didn’t need anything other than valve guide seals. Unfortunately the bike still smokes on start up and still uses a little oil.  After a few tests the conclusion was it’s a valve guide and at this juncture I’m going to put up with the start up smoking and a little oil use. As a side note my riding style of lower RPM never on the REV limiter no doubt has contributed to the longevity of the motor but it just goes to show that even smaller displacement four stroke motors can and do last a long time. 

 

So why the 390 kit?  First of all I was happy with the  350 power for my riding purposes I just wanted a little more torque out of the corners because of my size. My initial impression was wow more low and mid range power and it still revs to the moon. I didn’t feel any more vibration than before.  It didn’t change the engines pulse and as a result the nimble handling is the same. I’ve experienced only upside not a single down side to this point, the only thing I can see is it perhaps generates more heat. Its summer time and I’ve ridden the bike on real tight trails first with a stock coolant mixture and had some overheating issues. I’ve since put in waterless coolant and haven’t experienced and issues.

Before I went with the big bore kit I looked into just updating my 2011 motor with newer motor components because they are supposed to have seven or eight more horsepower than mine, turns out that’s wasn’t possible even the cases are different.  A friend of mine bought a 2013 350SXF to convert into a trail bike like mine and I was anxious to compare the two horsepower and torque wise. Before we were able to hook up I had the chance to ride a new 2014 350SXF on a MX track. I was anxious to see if the new bike had more low end power than my stock 2011 350. For me anyway it felt as though it didn’t have much or any more down low power. I also had the chance to ride on the same day a 2013 350SXF with a steel liner 390cc kit. That bike was a different story it had a lot more low end torque and I came away feeling I could use this bike for MX.

Wayne and I finally hooked up, he rode mine and I rode his and the results were interesting. Just like my rides on the MX track with the new 2014 350SXF and the 2013 350SXF with a 390 kit my  2011 350/390 has so much more low end torque than his 2013 350SXF it just reinforced my decision the make mine a 390 a good one. I won’t have to be thinking about buying a new bike again for awhile. The next thing I want to try is a tubeless tire set up. I recently bought a 2012 KTM 500EXC and it came with a Tubeless set up and I’ve been very impressed so far. I have a few friends who use the tubeless set up on their race bikes and swear by it. They race cross country, enduros and desert. One of my friends works closely with the Tubliss people testing various tire combinations. He rides almost exclusively in the woods and has gotten his set ups down to as low as two to five pounds front and rear and he rides a 450 and is like six four and 230. I tried a trials tire on the back of my 350 in the woods and it didn’t work for me for two main reasons I only had my 19” rear wheel to put a trials tire on at the time and the choice of tires was very limited. I’m a rear brake dragger and tend to steer with the rear end. For me the trials tire didn’t stop nearly as well and tended to push the bike into the corners.

Who knows what will happen in the next three years, hopefully I’m still riding and maybe I’ll write another article about the long, long term KTM 390SXF.

Doug 21J