Triumphrat

bmca · 12-02-2012, 11:16 AM

I recently bought a 2007 Bonneville with Staintune mufflers on it. When I'm moving and I release the throttle, it starts to backfire and sputter. If I maintain just the slightest bit of throttle, it doesn't backfire. But as soon as I let go of the throttle, I get the backfiring.

This is my first motorcycle, so I have no idea if this is normal. Is it? Is this something I should get fixed?

clydeturbeaux · 12-02-2012, 01:09 PM

Is it actually backfiring through the carbs or are you experiencing a few pops and burbles from the exhausts?
If it's the latter, it's quite common and can be minimized by turning the air bleed screws out a little at a time.
Has your AI system been removed?
There's a wealth of information on here regarding this. Maybe look for "popping on deceleration" or "popping on overrun" in the search function.

Good luck!

bmca · 12-02-2012, 07:31 PM

Thanks for your response! I have found a few other threads on this topic, as you suggested. But I'm so new to this that it's hard to make sense of a lot of them. How can you tell the difference between backfiring through the carbs and the "pops in the exhaust?" I think it's in the exhaust based on how it sounds, but wondering if you can explain the difference.

How would I tell if my AI system has been removed?

Sorry for the super-basic questions.

KitNYC · 12-02-2012, 09:33 PM

It's very hard to explain the differences between sounds over the 'net. You ever go to Doc's on South Congress for bike night on Tuesdays? I know there'll be at least a couple people there who can listen to your bike and tell you which it's doing.

Cheers,
-Kit

clydeturbeaux · 12-02-2012, 09:36 PM

I'll try to explain the difference as best I can:
Backfiring through the carbs is rather loud by comparison and happens a lot closer to the seat/sidecover area. It is sometimes accompanied by an unpleasant smell (if the air cleaner element gets singed) and poor running.
The popping or burbling in the pipes are more closely associated with the sound your uncle makes breaking wind on a leather couch,
(more subdued, but still embarrassing) and usually only happens upon deceleration.
It's pretty easy to see if your AI system has been removed by looking for two silvery pipes right next to your spark plugs (just outboard of the plugs). They'll have rubber hoses connected to them which disappear up under the tank.
If you find only two little plugs there, your AI system has been removed. This is by no means a completely definitive answer as some folks disable it without removing the pipes by blocking the larger (unseen) hose up under the tank with a marble.
See if you can find some local RATS to friendly up with for better advice. Usually they'll be more than happy to provide guidance for the low price of a beer...

Good luck and keep us posted!