Bike will only run on center 2 cylinders,it was woking fine and then it started to run ruff and now it only will run on 2 cylinders,the other 2 have spark.could it be a timing chain?or fuel? when i removed the plugs they are dry.

Check fire on the coil for that cylinder. Sounds like a bad coil pack. That was just one of the things wrong with mine.

Could be fuel pump pickup has come loose or ????

It sounds like your on the right track, the next step is to do a compression test to verify good rings in that particular cylinder.

if its a twin cylinder (2 spark plugs) one cylinder isn't firing...

possible issue on timing and or internal overheating.

KTMs vtwin timing is a little hard to decipher so i rather you have your bike brought to a KTM service center for overhauling.

please do not use the bike before it gets repaired. this king of issue may damage your cylinder

double check your firing order and make sure all wires and hoses are plugged in good. when you pulled the push rods out did you make sure they went back exactly where they came out because there are 2 different lengths.

scan check egr valve make sure its working. check plug wires and vacuum hoses +pvc valve make sure its not stuck open.bad or dirty fuel injections.causes rough idling.if all is good do a compression test to check for weak cylinders or low compression.

single cylinder engine doesn't have much adustment that you can play with. the best suggestion is to change the plug, since the mower starts and runs. that is most easiest and cheapest fix.

Can you confirm if the bike, once running, runs well below 3000rpm?

I've experienced this model not liking pilot jet usage due to an accumulation of fine particles in the fuel which build up and block the pilot jets.

Above about 3000rpm, it runs on mains jets.

If this is the problem, you can use a high quality fuel filter but it must be high flowing as this model drinks fuel.

Looking forward to your post.

Hi you should change the coolant temp sensor this is a white sensor on top of the intake and is part ot the computer system.