2017 KTM 500 EXC-F: Uncorked and Retuned

with 11 Comments

There is no doubt that the 2017 KTM 500 EXC-F is one of the most powerful and best performing dual sport bikes on the market right now. Even right out of the box it blows away the competition with it’s 62 horsepower. The crazy thing is, there is even more power to be had if you own one in the United States. The noise and emission restrictions set forth by the federal government are so strict, the bike is actually restricted.


FMF Pipe & Euro MAP: I’m Done Right?

The first thing I, and most people do, is add a pipe for better sound and more power. I went with an FMF 4.1. Upon installing an aftermarket pipe, more fuel is required when you let the bike breathe better. I had the Euro map installed at a KTM dealer afterwards and the bike felt great with the exception of some occasional popping from the exhaust on decel.


Why Go a Step Further?

At this point I thought I was done. What more could I possibly expect from this bike? It rips! Well, for one I wanted it to live. And two, I hoped the Euro map was enough fuel for the FMF but I really had no idea if it was actually dialed in properly. I also read a ton a people were desmogging theirs and pulling the reed cage from the air intake boot. At first I was against this until I saw just how restricted it was. The only problem with pulling the reed cage would mean the bike would require even more fuel to run properly. Well after speaking with Chris Blais from Blais Racing Services, he told me he could remap my ECU which would allow me to pull the reed cage and have the proper air/fuel ratio for my FMF. Even with the Euro map installed, these bikes run about 16:1 air/fuel ratio which is lean! That is dangerous for a motor at 7000-8000 rpms. I was sold on giving it a shot, but I didn’t want a bike that ran rich and got crappy fuel mileage. He reassured me that would not be the case.


Uncorking My 500 to It’s Full Potential


Blais remapped ECU

I shipped Chris my ECU and he had it remapped and back to me in no time at all.

DeSmog & Breather Relocated

After the newly mapped ECU was installed, it was time to demog. I installed the Blais block off/ delete kit and relocated the crankcase breather hose. It is a very simple kit and easy to install. I won’t go over every single step because the instructions are so easy, but you just pull the air valve out of the cylinder head and block it with the supplied plug. Then remove the fuel vapor and vacuum lines and block off the canister valve vacuum hose fitting in the intake. Once that was done, I relocated the crankcase breather hose so there wouldn’t be any more dirty crankcase air contaminating the airbox with oil. I capped the airbox port and ran a new line from the valve cover to outside the airbox. The kit comes with all the vacuum caps, hoses and plugs needed to do all of this. There is also a 6 page instruction sheet so there is no guesswork.

Note: According to Blais Racing, the canister valve can be unplugged and completely removed without throwing an engine light if you already have the Euro map since the Euro model does not have the valve. Therefore, I will be removing the valve all together!




Pulling the Reed Cage

KTM started putting a reed cage in the air boot in the 2017 models. It is designed to reduce noise. That is it’s only purpose. They look just like the reeds out of 2 stroke. To pull them out, I just had to pry the rubber boot away from the airbox. It is cemeted on and doesn’t take much effort. A 90° pick did the job. Once the rubber boot was removed, I grabbed the reed cage with some pliers and pulled it right out. It took a little prying towards the end, but it was much easier that I thought. After that…that’s it. You’re done. Some companies sell a fancy tube to install in the air boot claiming the rubber intake boot can collapse on itself under heavy throttle. This is not true.

2017 KTM 500 EXC-F Reed Cage
Removing the Reed Cage
Much better flow!
Desmogged, breather relocated, and reeds pulled



The Results

  • more throttle response
  • still gets 54 mpg
  • piece of mind knowing my A/F ratio is correct
  • no decel pop
  • pulls hard throughout all rpms

On my test ride I could feel a difference right away. The bike was snappier and more responsive. This is mostly from pulling the reed cage and having the proper air/fuel ration to do so. The bike screams. Before, with just the Euro map, it seemed to make it’s peak power in the mid range. Now the bike pulls hard throughout the entire rpms. There is no more popping on decel anymore either. On top of it all, I calculated my mileage after a 109 mile ride with a mix of highway, hillclimbs, hard acceleration, and trail cruising and I got 54 miles per gallon. I’m very happy with how my 500 runs!



Product Links

BLAIS RACING: 2011-2018 KTM & HUSQVARNA Custom ECU Bike Mapping

BLAIS RACING: 2017-2018 KTM 450/500 EXC/ 2017-2018 Husqvarna FE450/501 Block off/ Delete Kit & Breather Hose Relocation for Racing


Disclaimer: these mods are for off-road use only and are not street legal. 



Follow Pete:

Do more with less! That is my motto lately. I love getting outdoors and exploring new places, usually on my KTM motorcycle. My wife, Anna, and I recently bought and built out a Sprinter van to do more of the things we love. Traveling and seeing new places is always at the top of our to-do list.

11 Responses

  1. Chris Blais
    | Reply

    Glad you liked it Pete. There is a lot of potential left in these bikes with the right tuning. Have Fun and Ride Safe!
    Chris Blais
    Blais Racing Services

  2. Dickie Doyle
    | Reply

    Thanks for the write up and pictures. I’m very curious where you got the 62HP number. The 500’s and 501’s I’ve had on a Dynojet dyno show nowhere near that. A fully restricted one is showing right around 40HP.

    • Pete
      | Reply

      That is the factory horsepower rating for the 17 KTM 500 EXC-F. That number is at the motor and is obviously going to be less at the rear wheel.

  3. Leo
    | Reply

    Thanks for the write up. I wanted to know how you like the bike after removing the reed cage. It’s been a couple of month since your write up and wanted to know if you still feel as if there is no need to install a fancy tube. Have you had the boot collapse on itself. I have a 2018 Ktm 450 exc and would like to do the same.

    • Pete
      | Reply

      Hey Leo, I am absolutely loving the bike and the power it makes. There is still no need for a fancy intake tube. The intake boot will never collapse on itself.

  4. David LeBlanc
    | Reply

    Great write up, I have a question. My bike 2013 KTM 500 EXC, Euro Tune/FMF/de-smog/Airbox Mod/49 tooth rear sprocket. So my bike doesn’t lug, will straight die on any rock and boulder I’m tractor over, unless I’m riding the clutch and keep the rpms high, which is annoying.

    Will the Blais ECU tune solve this problem?

    • Pete
      | Reply

      Hey David. Thanks. That sounds exactly like what my 690 did before I re-tuned it. My 500 never flamed out like that, but it sounds like a tune issue. It wouldn’t hurt to give Blais a shout. He is very knowledgeable about these bikes.

      • David LeBlanc
        | Reply

        Hey, thanks for the quick responce. Got the ECU in the works. What did you notice with the addition of the clutch weight?

        • Pete
          | Reply

          I didn’t change anything with the clutch.

  5. Daniel Hall
    | Reply

    I have a 2018 500 excf and went thru just about the same process to derestrict it. I added a FMF 4.1, removed and plugged all emission equipment, added a Vortex Ecu and pulled the reed cage out of the intake. The bike started making power all the way to redline, and it makes a lot of it. 4th and 5th gear power wheelies. You got to love that. This is definitely worth the money and hassle. If you can do it all at once the difference in power is astonishing. What a great bike.

  6. Paul
    | Reply

    My 2017 450 six days I put a titanium Mega Bomb 4.1 on refuses to knock down RPMs and a lot of Poppin daring deceleration need help too much money in it

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