KTM 250 SX-f SPLUTTERING

[ktmalltheway]

Hey guys,

I have been riding motorbikes for years from mini motors when i was younger scooters on the road when i come of age and then my XR 110 and now my beast KTM 250 SX-F with a few mods like a boost bottle to increase acceleration, off road tires and FMF fatty racing exhaust. She has been running well since purchase until now a few days ago my KTM started spluttering like it was running out of fuel but unfortunately this was not the problem, I have been looking at some classified ads KTM exhaust sites to find out some information to see whether the exhaust was the problem i don't think it is, there is barley any rust let alone holes and it sounds the same as normal when it's not spluttering. The spluttering occurs in the top end of gears and when i let go of the throttle it is driving me crazy!!!

Any help would be greatly appreciated!!




Thanks guys

[GS_in_CO]

Steady throttle while in a high gear? High or low RPM at that time?

When you let off the throttle- any gear? Any RPM?

Bike is new? Or just new to you with N previous owners?

[ktmalltheway]

It is new to me with one previous owner (2nd hand) and it splutters in the high RMP When i am supposed to hit powerband of every gear but when i release, High RPM it don't seem to be that bad in 1st-2nd but 3rd-6th it splutters on as the revs are dropping if that makes sense?

[GS_in_CO]

But it used to work?
Any chance you put old lawnmower gas from a dusty can in the garage in it?

Nothing real obvious suggests itself to me. Missing at high RPM can be weak battery / ignition system.
You should also check the spark plug for clean and correct gap. That doesn't change suddenly but is part of checking the basics. Check spark plug wire tight at both ends. Check 12V wires to coil clean and tight.
Then it might get harder with ignition trigger not working right at high RPM.