My dads V-force 700 backfires when you start it up, it is pretty cold around here, could that have somthing to do with it, should we be conserned about it, we just put a HMF pipe last summer right before winter hit and we havent rode it for a while then the other day we went out to ride it and now every time we start it it backfires. is this a problem, and if it is how can we fix it.

 

Fired up the P650 yesterday after it was hydrolocked with fuel (after changing oil, filter) and the backfire sounded like a 30-06 went off in the garage, yeeeowww.

 

yea i know when we fire it up in the garage it sounds like a shotgun

 

haha.

 

The backfire is most likely due to a lean condition. Does it do it when cold and going on the throttle? Any vacumn leaks in the intake area? Did anything in the intake area change? like kn filter or removing air box lid?
When the pipe was put on, did the instructions say anything about jetting richer?

 

well when we put the pipe on we took it into a action motorsports for a check up and they rejeted it cuz the pipe didnt come with directions. it backfires goin down the road when it is cold and when it gets warm it still does it just not as much

 

If you'vealready jetted it/Plug Chopped & checked and it was running perfect before winter try turning out the mixture/pilot screws 1/4 more turn. Should clear it up. Bikes tend to want a richer fuel mixture setting when the temps plummet[img]i/expressions/face-icon-small-happy.gif[/img]

Tuff

 

I've got an old John Deere 175 with a 14 hp Kaw motor in it that sometimes backfires and sounds like my 12-gauge a second or two after you turn the key off when finished mowing the lawn. Nice flame comes out the muffler too! [img]i/expressions/face-icon-small-shocked.gif[/img]
My new BF750 does a little backfiring/popping too, but I just got it Saturday and it kind of seems like it mainly does it when it isn't fully warmed up yet. I do have a copy of the TSB though, so I'll take it back in for the needle replacement if it keeps it up.