backfire

[chris6888]

I put the stock airbox and filter back on my bike and it runs so much better. I resynced the carbs and it runs really good but has a backfire sometimes when i let off the throttle. It also accelerates good through first second and third but infourth and fifth it hesitates will adjust jets on top of carb will help with this.

[Mercaholic]

What type of exhaust is on the bike?

[chris6888]

4-1 hindle header

[tom203]

I put the stock airbox and filter back on my bike and it runs so much better. I resynced the carbs and it runs really good but has a backfire sometimes when i let off the throttle. It also accelerates good through first second and third but infourth and fifth it hesitates will adjust jets on top of carb will help with this.

Did you ever doublecheck that main jet size (150 ?) ?
Anyways, on my bike about a month ago, I noticed a backfire when I backed off throttle, but it ran well otherwise, so I figured a carb cleaning was calling this winter. But two weeks ago, it stumbled in mid range- pulled plugs, #2 was fouled,so I sucked on vacuum hose and found it was leaking to #2 carb. Plugged carb fitting, ran in prime and no more backfire- apparently the unburned fuel was igniting in exhaust at low throttle settings. So check your petcock to rule this out.