hey guys,

I was riding into work today and got a mile and a half from the house, riding in 2nd then the bike back fired and the speed-o went down to 0 then back to speed. I went about 100 more yards and it did it again, and then again in about 20 yards. I turned around and rode home and it didn't happen again.


Any ideas?

 

could be a loose battery connection.....could be alot of other things but this sounds alot more like battery, or at least electrical system.

 

I just put a new battery in it last Tuesday and remember tightening down the leads, but that was going to be the first thing I checked.

Also, the lights were still on and the bike never lost power, just the speedo dropped.

I've read about pinholes in the tube in the tank, so I think I'm going to check that next.

 

One other thing... after it back fires when I slowed to a stop it seemed like it took awhile for the bike to get back to idle.

 

What might be helpful is what bike you have, how many miles, mods, etc.
When you installed the new battery did you check the ground connections? You could have an intake or exhaust leak causing the backfire, a dirty IAC can make for a bad idle.
Check to see if it threw any codes.

 

Thanks man, it's an 09 FXDC, about 14.5k miles, stock AC, vance and hines slip ons.

I didn't check the grounds when I put the battery in, but I rode every day last week and it didn't have this issue.. I'm at work right now but I'll try and pull codes when I get home.

 

I doubt it's the battery. It should run just fine off the charging system. It sounds like a loose or bad connection somewhere to me.

 

Check the coil. Make sure it's properly connected everywhere.

 

You report changing the battery.
Any chance you have a short to ground from the positive post/cable to frame/cover.
Rather tight area.
A slight bump and you get a temporary short...system farts and then regains composure.

 

Vehicle speed sensor, or battery loosing connection. More than likely vehicle speed sensor if you get a check engine light