Hey all....well while i was away working up north for around a month my ds sat and never started. I get home and fire her up take off and she is sputtering and popping under half throttle......i can pin it and screem her wide open but as soon as i let off and try to open the throttle up again she spits and backfires......it is a colder here so i put in a larger main jet and adjusted my needle like i always do for this time of year.....NOTHING changed. After the quad warms up to say about 190 it runs great....any ideas?

 

Remove your pilot jet and check for fuel gumming in it. Clean it really well and reinstall. If this doesn't fix it, you might put a slightly larger pilot jet in it.

Typically if they won't run right off idle when cold, the pilot is not allowing enough fuel. The bike will run fine when at full temp of if you can stumble through the rough part and get on the main jet.

If a bike sits for a month, it is easy for the liquids to evaporate out of whatever fuel is sitting in the very tiny pilot orifice which can simulate an undersized pilot due to blockage.

 

Alright, i will pull her apart and check that out.