Back Firing

[Snoek]

I installed a Y-pipe on my ADV about a month ago and have since experienced some problems with back firing. It only happens when the exhaust is hot and when I decelerate. I commute in central London on a daily bases and the bangs are so loud
(I mean loud) that I see people jump a mile or in some cases, jump for cover (not kidding). At the begging it was fun being a GS hooligan freighting the life out of London pedestrians/road users but the novelty has worn off and I want to get rid of the
back firing. How can I resolve/decrease the back firing? Is back firing bad for the bike?

 

[Steve]

You need to make sure that all the joints are well sealed with exhaust sealant. The slightest air gap can lead to some wonderful backfires on the overrun.

 

[Greg Masters]

Snoek

Your options would appear to be:

1. Fix any leaks in the exhaust system
2. Remove the Y-piece and replace the cat
3. Don't ride the bike
4. Put up with it
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   Greg

 

[Hedgehog]

Yup.....

Numerous threads on this subject if you use the search option.

Basically... Yes it will backfire without the cat.... even the old 1100 with standard, well fitting exhaust did.... but making sure the new pipes joints are well sealed will reduce the problem.

There has been some talk of backfiring damaging the valves on some jap bikes, but never on a beemer. Not a worry.

Brill for getting rid of couriers/scooters/tailgaters.
Currently working on obtaining that FP1 flamethrower effect to go with it.

 

[Gecko]

Yep , my standard 1100 let's rip now and again - I have even frightened myself sometimes Lovely big BANG !!!! then on up the road with a big grin and a glance back in the mirrors to view the aftermath of old ladies shaking their umbrellas and overweight business men clutching their hearts in shock

 

[Strangelove]

Had the same effect with the y-piece and original end can set-up. A high velocity 7.62mm sniping rifle type noise. I sorted it out by fitting a remus end can. I now have a sort of menacing "artillery on the edge of Baghdad" type rumble where the backfire used to be. Of course the bike is now generally noisey all the time. swings and roundabouts really!

 

[mikyh]

Backfire

The symptoms are of lean mixture in idling/low throttle. You need to manipulate the ignition/injection mapping with whatever is available to oilheads (I'm not familiar with oilhead details).
Miky

 

[Zwerver]

According to Wunderlich, the lack of volume in the y-piece
is the main reason for the backfiring...

 

[Madmountainman]

Booming bangs are a safety feature...

They let dumb ass myopic pedestrians know you're coming so they stay on the pavement instead of wandering out into the road before looking! However, if you do want to reduce the backfire try this; A mad Welshman passed this on during the Rhayader weekend. Take out the fuse which protects the engine management (No 5), turn on the ignition and open/close the throttle twice, turn off the ignition, replace the fuse and hey presto things should have improved. Apparently this works, so i'm going to try it out on mine... Two Bros blue flame belching and ear drum bursting delights will hopefully be reduced, but not entirely!!!