Backfiring just a little

[Thenewguy]

Hello again guys! I just wanted to tell everyone so far it's being a great riding season and my 83 gs 750t is handling it well!

The other day I was out riding for about 4 hours and I noticed for the first time that my bike backfired a little bit. By a little bit I mean one, maybe two small pops from the exhaust pipes. It happened when I was riding at higher speeds (maybe around 50-60 mph, 4-6 rpm). When I let off the throttle and just let the bike naturally de-accelerate, it will let out the pop(s), What is the cause of this? I had my carbs redone at a professional shop at stock configurations, new sealed airbox, new plugs, etc. I've being riding this bike with the same setup, no changes for about 2,000 miles now. Any thoughts? I'm guessing crud from the tank due to me running the gas level way down or it needs a valve adjustment. Any ideas are welcome. Thanks!

 

[tlepac]

If you don't know what the valve clearances are and the bike has more than 4000 miles on it then that would be a good place to start -----from what I have read on the site

 

[tmacey45]

Backfiring through the exhaust is usually due to a lean condition. I would start with a plug check first, see what the carbs are doing. You want to see a dry, light brown/tan color on the plugs. If they appear grey or a bit white, it's running lean. It's a good place to start....

 

[bradleymaynar]

Not that this is any way related to what you're hearing, but reading a Motorcycle Consumer News years ago, a Ducati rider asked basically the same question to the editor about the popping on deccel. The answer was to hold in the clutch. :lol:

Brad bk

 

[Guest]

If it just started tighten down your headers

 

[rideOn]

after adjusting the valves and rebuilding the carbs, mine backfired a little. I replaced the plugs and set the gap to maximum tolerance. I also began to run 93 octane, which burns a little slower. I took about a 4-hour trip sunday in the mid-90's and no backfire. After she cooled, I checked the new plugs and all had a good color to them (light brown / tan)except #4. It was a light gray, so I turned it about 1/4 turn to richer. hope that helps

 

[Guest]

I am running a Vance and Hines 4 into 1 exhaust with K & N pods with a stage 3 jet kit on a GS1000E. It is my understanding that some muted pops on deceleration are normal for my setup with everything adjusted properly. I don't think your stock setup should do it much, but air leaks in the exhaust as chef1366 indicated could cause it. It would be a good opportunity to remove your exhaust bolts, making sure there is anti seize lube on the bolts. They are easier to deal with, with the bike warm.

 

[Thenewguy]

I just wanted to let everyone know the progress of finding the cause. I spent a little time yesterday inspecting everything. The air/fuel mixture is good, I have a brownish plug. No leaks in the exhaust or intake setup. At this point I'm betting it needs new exhaust gaskets where the manifold is or it needs a valve adjustment, or both. I say the gaskets because I did a valve adjustment about 1500 miles ago.