 Backfire
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Joined: Sep 2006
Posts: 231
Adjunct
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OP
Adjunct
Joined: Sep 2006
Posts: 231 |
Every once in awhile my bike backfires, usually after I fire it up after a short (5 -10 minutes away). Otherwise it runs great. I removed the AI and rejetted the carbs after putting on some reworked pipes I bought from Hermys a couple of years ago. I am a dumbass and didn't write down the jet sizes, so I don't know what they are. The bike has about 27k on it.
Any suggestions before I pull the carbs (not a fun task) and try to rejet?
Thanks,
Ted
Send lawyers, guns and money, cause the sh*t has hit the fan!
-W. Zevon
2020 Bud Ekins T100
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 Re: Backfire
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Joined: Aug 2007
Posts: 10,730 Likes: 6
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,730 Likes: 6 |
Mine backfires on occasion too, I don't worry too much about it. Re-jetting is a lot easier if you just drop the bowls and take the jet collar out with an 8mm wrench and then put your jet on that.
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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Re: Backfire
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Joined: Jan 2005
Posts: 8,639 Likes: 3
Old Hand
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Old Hand
Joined: Jan 2005
Posts: 8,639 Likes: 3 |
Is it backfiring through the intake? If so, make sure that you are leaving the throttle completely closed when starting.
Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python
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Re: Backfire
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Joined: Jan 2005
Posts: 121
Adjunct
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Adjunct
Joined: Jan 2005
Posts: 121 |
Don't know if this is related, but mine never backfires, but last week it backfired twice on starting and while coasting to a stop, through exhaust. I wondered if it was due to the gas I bought. I usually try to buy 89 octane gas without ethanol. This time I bought 87 with 10% ethanol. Coincidence?
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 Re: Backfire
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Joined: Jun 2006
Posts: 2,626
Loquacious
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Loquacious
Joined: Jun 2006
Posts: 2,626 |
If you touch the throttle while starting, the throttle position sensor alters the ignition timing. This can cause a backfire and, worst of all, the dreaded AIRBOX KA-BLOOEY. 
Steelheart- '03 Speedmaster Black/Yellow
The Hayabusa Killa
16" Shorties/140 mains/Airbox drilled
Procom CDI
"There is no cure for Celibacy. But we can treat the symptoms."
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Re: Backfire
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Joined: Sep 2006
Posts: 231
Adjunct
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OP
Adjunct
Joined: Sep 2006
Posts: 231 |
Ah well, I said I was a dumbass, didn't I. After reading the replies to my post and then mining the performance posts, I decided to check my air filter. Well there was some crap in there, including an intact leaf.(don't ask what kind, I am a dumbass after all) So I blew out the filter with my compressor for a short term fix. Am ordering a new one tonight. Don't think I am up for a $300 airbox refit or the one described on the ghetto freak site. If this doesn't work, I'll think about rejetting.
But, my Haynes manual talked about pulling the bungs and checking for debris, etc. I scoured the entire airbox and couldn't find any.
BTW: A led booklight with a gooseneck is a fine tool to use to see into small spaces.
Ted
Send lawyers, guns and money, cause the sh*t has hit the fan!
-W. Zevon
2020 Bud Ekins T100
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Re: Backfire
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Joined: Jul 2008
Posts: 1,440
Learned Hand
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Learned Hand
Joined: Jul 2008
Posts: 1,440 |
Quote:
If you touch the throttle while starting, the
throttle position sensor alters the ignition timing.
AH HA! So that's the reason! If the TPS is unplugged, does the backfire issue go away?
'08 America Blue/White; Custom Headlamps, Custom Lowers, Clearview 20", Bafflectomy
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