KTM 450 EXC Enhancements

2011 KTM 450 EXC Motorcycle

This is part two of my 2011 KTM 450 EXC review. In Part 1, Deciding on the KTM 450 EXC, I talked about my research and decision process that lead me to buy the KTM 450 EXC.

When I bought my 2011 KTM 450 EXC a few months ago, I already knew it would require some changes. I’d read many blogs and discussion boards talking about how poorly it ran because of everything KTM had to do in making it street legal. Rather than jump into the changes, I wanted to ride the bike for a bit and decide for myself what needed to be done. I’ll break them down into mandatory changes from day 1, and other changes you should probably consider depending on your riding habits.

Mandatory Changes from Day 1

Fortunately for me, the Motor Cafe in Sunnyvale, CA delivered the bike to my home. The primary reason is that with the stock jetting it runs like crap. I don’t think that even KTM would be offended by this statement. They already know it. In order to pass emissions for street registration the carburetor jetting is very lean. My bike would hardly idle, hesitated like crazy on acceleration, and the exhaust popped like crazy on deceleration. Basically, it was unrideable.

I have a friend that owns a KTM 450 XC-W, the pure off road variant of the EXC. He was kind enough to mess with the carburetor settings to at least make it rideable, but the improvement is marginal. Greg,the KTM sales guy at the Motor Cafe, had told me I would want to put in a JD Jetting Kit. He was right. I also talked to Maico Bill at HT-Racing. He put the XC-W jetting into his EXC. In the end, it seemed like the JD Jetting Kit would be simpler to install, and be a little less edgy than the pure racing jetting of the XC-W.

The kit includes multi-tapered needles designed specifically for the 450 EXC. Installing the JD Jetting Kit was relatively easy, even for a novice like me. I was a little concerned about taking apart the carburetor, but the instructions from JD Jetting were quite good. Along with pictures from their web site, I managed to change both the main and pilot jets and the o-ring linkage. If you have tried to adjust the fuel mixture screw on the carburetor, you probably also found it impossible to reach with your hand, or any kind of tool. I also put in a new fuel mixture screw that is designed to be easily adjusted by hand.

Once the new jetting was installed, the performance was amazing. No more idling problems. No more hesitation. Hardly any popping on deceleration. This is a “must do” change to any new KTM 450 EXC. This is probably the only thing I consider a Day 1 change. There are other changes I’d considered highly desirable, but you may want to put on a few miles to get a sense for the bike, and your riding environment. I’ll talk about these next.

Highly Desirable Improvements

After riding the bike on the street and trail, I realized it is geared to do 75 mph on the highway. I don’t know about you, but for me, I wanted much better low-speed performance. I didn’t plan to do any long highway rides. In stock form, the 450 EXC comes with a 15 tooth front sprocket and a 45 tooth rear sprocket. This was fine for the street, but I hardly got out of first gear on the trails. I changed to a 14 tooth front sprocket and a 48 tooth rear sprocket. This allowed me to keep using the existing chain. This gearing was still reasonable for street riding, even highway speeds, but provided much better low speed performance. I could now get out of first gear at low speeds, and grunt around in second gear. Second gear provides much less abrupt throttle control than first gear for tight trails or tough conditions.

Is this the ideal gearing for the 450 EXC? That probably depends on your riding. At times, the gearing still seems a little tall. I’ve talked two other people with 450 EXCs and they have changed to a 13 tooth sprocket on the front, and a 50 tooth sprocket on the back. I may experiment with this gearing some day to see if it better fits my riding. I suspect it may, but I’m reasonably happy for now.

Now that the bike was running great, and geared for trails, it was a lot of fun to ride. This lead me to discover the next highly desirable change. Sitting on the bike for a couple of hours was a pain in the butt. The stock seat was quite hard. But even worse, had squared off edges that dug into my upper thighs. A friend of mine has an Enduro Engineering seat and a Guts set for his KTM. I decided to replace the stock seat with an Enduro Engineering Standard Height Soft Comfort Seat. This was a major improvement. Now my arms and legs get tired before my butt gives out.

Other Changes or Improvements

I’ve made a couple of other changes that I consider optional, but probably highly desirable. The stock mirrors on the 450 EXC are amazing. Very high quality. Very little vibration on the road. Very likely to break off in a crash. I bought a very inexpensive KTM mirror that folds away into the handlebars when riding off road. On the street it isn’t as good as the stock mirror in terms of visibility and vibration, but since I mostly ride off road it works for me.

The license plate holder had these funky reflector holder that sticks out the sides. It probably wouldn’t survive a crash. I removed it and put some stick on bicycle reflectors on the fender. I also mounted the license plate sideways to minimize the likelihood of it catching on something.

Although you may hear about problems with turns signals, the 2011 KTM 450 EXC has improved rear turn signals over previous years. They are now flexible and won’t break in a crash. Trust me on this, they don’t break in a crash. I’ve also had people ask me about changing the exhaust, or removing some of the packing in the stock exhaust. At the moment, the bike has more than enough power for me. If and when that isn’t the case, I may explore an after-market exhaust for some more horsepower.

And that’s it. The KTM 450 EXC is now a much better off road motorcycle than I am a rider.

In part three, I’ll talk more about my riding experience and performance of the KTM 450 EXC, both on and off road.



  1. Scott Wilson says:

    Where did you get the fold away mirrors for the KTM 450?
    Thanks in anticipation.

    • I bought mine at my local KTM dealer. It is a stock KTM folding mirror, but it is actually an Acerbis mirror. It rotates on a ball within a bracket you mount on the handlebar. I put mine on so if I rotate it to face backwards it then can be rotated sideways behind the front number plate. Here is a link to the mirror at the motorcycle superstore:

      • I just uploaded a post on the Acerbis mirror mounted on my KTM 450EXC. It includes two pictures showing the mirror rotated upwards for street riding, and rotated behind the front number plate for off road riding. Here is a link to the post.

  2. Hey there, I gotta tell you some other great things I’ve done on my ’09 are: trailgear step up stator with dc conversion kit (charges much better no need for a step up battery after this), h4 headlight upgrade from pmxtec (essential if you ride at night at all) pro motion bead locks and a wheel balance (before the tires wear from the imbalance) . I upgraded all the lights from sicass racing’s stuff to give it more of a dirtbike rear fender look and I prefer led’s. Zeta turn signal hand guards and removed the stock ones. I too just got some cheap fold in mirrors. Keep the tires, I don’t care what people say those sixdays are great with good wear for a dirt dot. I also changed the gearing 14 front and 50 rear sprocket with an xw chain. Oh and I almost forgot the best one!!! Akropovic carbon tip exhaust, surprisingly not as loud as I thought it would be, only loud at higher rpms. I too did the jd jet kit and removed the air pump and all the emissions, runs much cooler but then I opted for the factory rivet on ktm cooling fan, this thing rocks of you find yourself in tight trails!!
    Anyway enough bragging, sorry about that my everyday car is a pile this is my pride an joy
    Cheers and good luck!

  3. Sorry, the stator kit was from trailtech not trailgear, trailgear is the Toyota stuff I put on my truck lol

  4. What made you choose the 450 model over the other sizes, (250-520)?
    I am trying to figure out what size to buy, but cant really find any guidance anywhere.

    • Hi Nikolaj,

      The only two 2011 EXC models available in my area are the 450 and 520. From reading discussion boards prior to buying the 450, it seemed like the 450 was most popular in areas with lots of trail riding, particularly low speed, single track. The 520 seemed to be more popular in areas like southern California where there’s lots of open desert riding. In northern California, most of my riding is trail riding. Even with the lower gearing, the 450 still has more power than I typically use. I rarely have a long enough open trail to crank the throttle fully open. If I truly used the bike as a dual sport, and wanted to ride it on the highway, I might have considered the 520. But, I ride almost exclusively on trails, so the 450 seems fine. I previously had the Yamaha WR250R, and thought 250cc was too small for some hills around here. If I was buying a bike today, I might seriously consider the new KTM 350 EXC. It might be closer to the actual amount of power I really need for trail riding. There are definitely two different philosophies around here regarding engine size. I like smaller engines such as the a 250 or 350, because you can crank them wide open and not worry about getting into trouble. I’m a relatively heavy guy, so the 250 is a little under-powered for me. The 350 might be ideal. Since my only choice was the 450 or 520, I went with the 450. I’m very happy with it, but I do need to use self restraint on the throttle. Others I know, like to have lots of extra power in reserve, and so prefer the 450, even if they rarely use all the power. Hope this helps. What type of riding do you expect to do?


  5. Hello All.
    I have a 2004 KTM450exc that I recently bought used. It has an older Rekluse clutch that seems to work fine but the bike pops a lot after letting go of the throttle? It seems to not decelerate all the way down but will do so after 3 to 5 seconds? Could this be a fuel mix issue? I have tried to adjust the throttle backlash and idle adjustment but no changes? Also thinking about trying the JD Jetting JDK002 Jet kit? Any input would be helpful…

    • My KTM ran very lean when I bought it. It popped a lot. I couldn’t fix it by just adjusting the carb. I installed a JD Jetting kit. It helped a lot. I still get some popping, but it is dramatically better. That may be your problem.


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