GS Backfires

[PBBoxer]

Only on over run normally, did it about 20 times in 200 odd miles today. Runs well but backfires every so often.
Y piece, standard can, otherwise standard I think.

Not overly concerned, just wondered if anyone may have an idea regarding whether its just rich or may have a known issue.

Its done 56k, fsh by bmw, last done this april at 54k

[bigblackfalco]

I give the HT leads a close inspection. Try doing the 'bike running in the dark' routine to see if it's arcing/ shorting anywhere.
Bailey.

[PBBoxer]

will do, ta.

Only bought the bike this week and generally very pleased with it at the price. Will check leads in the next day or so

[johnl]

i have an 1100ss standard but with y piece fitted. It backfires on occasion on roll off. It did not do it before the y piece was fitted. Like yourself i'm not overly worried and half expected it as a consequence of fitting the y piece.

Anyone else have the same problem? is this normal? other than going down the power commander route any solutions?

sorry to hijack your thread a little.

John

[r550s]

Mine (1999 s) backfires all the time on the overrun with a completely closed throttle. It started doing this when the BBchip was fitted, and the Power Commander hasn't changed anything. The a/f ratios look fine on the print-outs, but the tail pipes are always sooty and it'll actually manage a flame from the exhaust on a big overrun.
Isn't the motronic supposed to cut the fuel on the overrun to prevent this/aid economy? - the early K-bikes (LE Jetronic) used to do this, they had a microswitch on the throttle plate that had to be set properly to prevent backfiring, with a cigarette paper etc etc.
Any ideas?

[paulR]

What GS have you got? I've got a 2002 1150GS and mine used to backfire the same as yours when I had a Y-piece and the standard can. However, when I fitted a Scorpion can the backfires went away. I've had the Scorpion on there for two years now and cannot recall a single backfire. Whether that is down to the can or because it seals better to the Y-piece than the standard can, I don't know.

[PBBoxer]

It's a 2000 1150.
Has done 56k but looks like it's been looked after and has FSH etc etc.
It came with a remus that the guy removed, owing to being told by his I.A.M buddies it wasnt a great idea, so I intend to fit that tomorrow. Ive also a new set of 1150 RT air pipes to stick on, then maybe it'll go away. Got the bike as a year-round and touring hack and pretty sure it'll do the job fine.
Seems to be a litle play between off and on the thgrottle somewhere in the drive train, but again, very minor

[Gromit]

My 2001 R1150R (identical motor etc) used to backfire all the time with a Remus y-piece and can. Got to quite like it actually.

[Archie]

My 1200gs backfires all the time on the overrun, and it is completely standard.

If was a piece of software they'd document it as a new feature!

[PBBoxer]

We're off for a ride on Sunday, who's coming hehe

Devil's Bridge, Kendal, Teebay, Shap, Kirkstone, then maybe wrynose and hardknott just for fun

[johnl]

i bet the hardknot pass is fun this time of year!!

[nab 301]

Only on over run normally, did it about 20 times in 200 odd miles today. Runs well but backfires every so often.
Y piece, standard can, otherwise standard I think.

Not overly concerned, just wondered if anyone may have an idea regarding whether its just rich or may have a known issue.

Its done 56k, fsh by bmw, last done this april at 54k

My s never backfired (or should that be afterfired?) (backfire in theory being through the throttle bodies ) until I fitted a y piece.At that stage I removed the cat code plug and it was really popping and banging in the exhaust . It felt like it was running really rich so I replaced the yellow cat code plug and it was / is almost perfect. I discovered that one of the y piece connections was leaking and after curing this I've only had the occasional pop in the exhaust.
(If by backfiring you mean back through the throttle bodies normally valve clearances and balancing throttle bodies will sort this (and possibly the feeling of play in the transmission on an on off throttle.)
Nigel B

[johnl]

with what did you replace the yellow cat code plug?

[Boxadog 2000]

Funny that my 1200GS backfires as well with the Remus can.


But only when I have garlic

[nab 301]

with what did you replace the yellow cat code plug?

Running w/out the cat code plug defaults to the richest setting (which was too rich for my bike .), Which was why I replaced the original (yellow)
Nigel B