Purple - Blue Gradient

Emissions Delete Kit  for 2012-19 Bikes.  Stop the backfiring

Instructions for disabling / removing the emissions and fixing the kickstand on 2017 - 2019 KTM 250 / 350 / 450 / 500 EXC and Husqvarna 250 / 350 / 450 / 501 FE. These instructions cover various models and various years. Even though the parts remain the same, the locations on your bike may vary from what is shown here.

      Removing or disabling the air injection valve, must be done on these bikes, to stop the backfiring.  It doesn't matter how much fuel you add to the bike, after you have opened up exhaust flow.  Until the air injection valve is removed or disabled, it's going to backfire.

What you have in your kit is, the shorter kick stand bolt, a plug to plug the cylinder head when air injection valve is removed. The bolt and aluminum sealing washer for plugging the intake tract and 9/16” ball bearing used just to disable the air injection valve hose.


If your kickstand doesn’t stay down, then the dealer didn’t remove the long bolt and collar from the stand before it was sold to you. 


Remove the stock bolt with a T45 torx wrench (included in your tool kit with bike) and replace with the shorter bolt from the kit. Uses 5mm allen head. You can use loctite on it if you want, but we have never had one come out.


If you just want to disable the air injection valve, to eliminate the possibility of popping when you let off the gas, but keep the appearance of all the emissions parts in place, then just use the ball bearing.


Remove the little plastic filter from the end of the rubber hose going into the valve (on the 450 and 500 it’s on the other side of the bike), put the bearing in the tube and re-install the plastic filter. This will plug the air from entering the valve and fix the popping.


The rubber vent line that leaves the gas cap plugs into this plastic Y fitting on the right side of the bike by the radiator. You will want to pull the gas tube from the Y so that it breathese freely to the air. THis will ensure no vapor locking problems with the fuel system. There is still a one way valve in the gas cap to keep fuel from running all over if the bike falls over.


To completely remove the air injection valve, you will need to remove the seat and gas tank. You will remove the 8mm bolt that holds the valve assembly, shown here, to the cylinder head. The bolt is found behind the coolant hoses that are in the way. This is the location of the air injection valve on teh 450, 500 and 501 bike.


This picture shows the plug (provided in the kit) installed where the valve was removed. It will seat on it’s own when tight. It doesn’t need to be super tight. You can use blue or red loctite on it if you’d like.


On the 250’s and 350’s, this is where the allen screw plug goes. You will have to remove the 2 bolts that hold the air injection valve backet on, to get to the threaded hole. You can add some blue or red loctite to the allen screw plug and install. It will not fall into the port and will tighten before it goes to far.


Next you will remove the brass spigot on the right side of the intake tract. Remove the hose going to it. Use an 8mm long socket to get to it and unscrew it.

Use the bolt in the kit and aluminum washer to plug the hole.


Remove the hoses from each side of the frame and from the solenoid valve, which is on top of the crankcase. 

You can’t unplug the connector from the solenoid or codes will flash on the computer, so you can just leave this part here, or remove and zip tie inside air box.