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Buell Forum » 1125R Superbike Board » Archives 001 » Archive through May 04, 2009 » Backfiring? Fuel in exhaust? « Previous Next »

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Jdugger
Posted on Sunday, April 26, 2009 - 08:04 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

08 1125r w/ 34,000 miles.

I've taken to running it on the track mostly, and I'm noticing some things going wrong.

The bike will backfire when downshifted or if revved while standing. It's not a giant "gunshot" backfire, but you do hear the "pop.bbrrr.pop.brrrrr. pop", and it seems to be coming from the muffler, as in you hear the "pop" as if it's small explosion in the muffler.

100% stock.

Honestly, I sounds like fuel is getting into the muffler.

I can also stall the motor easily and consistently simply by quickly blipping the throttle from idle.

Anyone else noticing this?

I'd had HUGE surging problems, as in the bike would literally buck between 7 and 9k violently at open throttle, but that was seeming fixed by an entirely new fuel systems and new plugs.
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Jmr1283
Posted on Sunday, April 26, 2009 - 10:34 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

entirely new fuel system? is there possibly a air leak in the intake? now the bikes compansating by pouring fuel in.
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Easyrider
Posted on Monday, April 27, 2009 - 02:38 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sounds like some poor fuell cells, when you put the throttle down ons the gas return maps. I assume you always close the throttle when you shift and then open the throttle full.
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Jdugger
Posted on Monday, April 27, 2009 - 12:08 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I should add: The bike was doing this before the new fuel system.

Up Shifting: I don't notice because the bike's RPM don't reall drop... I'm either clutching/shifting (generally) very quickly or simply floating the transmission into the next gear with a throttle blip.

It's on DOWNshifting, where I'm using a little engine braking going into the corners that I notice the backfiring. You can feel it in the pegs -- at first I thought it was actually a belt tension issue until I noticed I could get the same sensation simply by revving and then closing the throttle while on the side stand.

I'm also fouling plugs every 3k...
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Chevycummins
Posted on Monday, April 27, 2009 - 12:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Check out the Baro sensor to see if it has the nipple pointed up and full of water.
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Jmr1283
Posted on Monday, April 27, 2009 - 12:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

good luck. maybe go to a dealer and have them reflash ur ecm. maybe something got screwy with the last map. also live chevy said, check all the sensors.
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Jdugger
Posted on Monday, April 27, 2009 - 01:01 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

> Check out the Baro sensor to see if it has the nipple pointed up and full of water

Thanks. Just looked. Installed correctly as per page 4-5/6 in the service manual and dry.
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Easyrider
Posted on Monday, April 27, 2009 - 01:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

100% sure it is the gas return map don't wurry too much when they added more fuel in a reflash the problem is gone check the flash too see what version it is and if possible upgrade.
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