Today for the first time, I noticed backfire. Happens while shifting up between gears.

Am wondering if this could be caused by an exhaust leak.

Also wonder if I could need new sparkplugs. Have 17,000 miles or original plugs.

Any other thoughts?

Bike is a 2008, 1200 custom, with screamin eagle mufflers, but no other mods.

Thanks,
Balloo

 

Occasionally I will get the popping in my exhaust on my 08 custom with cycle shack mufflers. It seems pretty random and I have not yet figured out exactly what I am doing that causes it. That said it is more likely to happen when its cold, but still occasionally when fully warmed up i'll get a pop when decelerating or when i let off to change gears. I don't think its anything to worry over. Plugs may be in order at 17k miles, but that really depends on their condition, and they are cheap so I would go for it.

 

first define "backfire"
If it pops out of the carb/EFI/aircleaner is a backfire .
If it pops out of the exhaust it is "stackfire" ,or exhaust pop.

lean cause's backfire ..i/e coughs/jerks pops out of the aircleaner.
can be a incorrect setting of acclerator pump,(or virtual fuel pump in the EFI) or CV boot leak.
also a aircleaner problem..(leaking) not enough restriction.

popping out of the exhaust can be caused by lean condition , carb/efi settings, or exhaust leak.
too low idle
wrong needle in slide /efi not calibrated correctly
pilot jet too small
straight through exhaust, (without proper adjustment to the intake system ) sometimes backpressure is good

these are just a few things , there are others ..
.
OK you just asked "what time is it ?"
Now you have to know how the "watch works " ..