Bonneville America Forums Forums Technical Forums General Tech Backfire, misfire,deadspots ?

Hello people, after a good few thousand miles trouble free riding with my 04SM, lately ive been getting some problems, Backfiring and misfiring and deadbands in the throttle.
i have read some of the threads on here and checked the airbox and bleed lines , full of gunky crap, i cleaned out the airbox and the bleed pipes, checked spark plugs and ignition box, also had a quick lookie in the top of the carbs just to make sure they were not full of gunk also.
Anyhoo after all this put back together and started bike up, it sounded and ran lovely , i thought i had solved it but!!! nope about a mile up the road misfiring and backfiring come back.

Any suggestions would be greatly appreciated, thanks

I had something similar, but no gunk crap, anywhere, it disappered for a while then came back. My problem eventually sorted after two years was the CDI unit. I managed to get it off triumph under warranty as it had been in the dealers 3 times from new but they could not find the problem. Hope you get it sorted, try swopping the CDI unit with another, if you know of any other speedy/America riders close by..

Bad gasoline? I've had serious problems with my car in the past from getting a tankfull of contaminated fuel...

Gurus?

--Jaeger

Last year in Belgium i had different fuel problems , for some reason using Belgian fuel caused vibration and bad running.
Ill check out the CDI Unit.
Ive ordered the Air injection removal kit aswell.

Thanks guys!

Bad fuel caused the same problems for me, mis-firing, throttle not crisp, and excess popping on deceleration. I just drained it out of the tank and replaced it with the regular stuff and problem fixed!

Hope your problem can be sorted out easily.

will tell you something funny had same problem last week no idea what happened but checked every suspect, and this morning discovered that wire is loose on one plug .....just changed plugs (they were really old) sorted wire and runs like new, took bike for a spin after 10 miles backfire like battle ship ........... ok let's go home and time to balance carbs and..................................I still can't belive I lost pilot screw!!!!!!!!! spring and small washer were on engine case and screw was missing!!!!!!

and was there in the morning cos checked and set 3.5 turn open

hope that your problem is the same small as mine just slowly check everything

Check the vacuum plugs on your carbs for cracks. If you have a bad vacuum plug it will cause what you're describing.