Author Topic: backfiring?  (Read 670 times)

Offline jim-d

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backfiring?
« on: August 18, 2020, 06:34:17 pm »
what would cause a 2002 c-10
to backfire thrrough the exhaust?  it is imtermittent and not when pulling out.  more gliding to a stop.  bike was running a little funky then started backfirig. but the engine smoothed out.

had the carbs rebuilt in August.  then the bike ran great.  sat for a month and started acting up.

Offline Boomer

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Re: backfiring?
« Reply #1 on: August 19, 2020, 03:19:23 am »
If it is when you have the throttle shut, it's probably an exhaust leak.
Somewhere the exhaust is letting fresh air in and the un-burned or part-burned fuel is igniting in the exhaust.
So, either you are running very rich and still have the PAIR valves fitted, or you have a leak in your exhaust.
Check the balance pipe, where the headers bolt to the engine, and where the muffler attaches to the header.
George "Boomer" Garratt
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Offline Chrome Megaphone

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Re: backfiring?
« Reply #2 on: August 19, 2020, 08:34:49 am »
I thought popping on overrun was lean? 
http://www.mikuni.com/tg_backfires_in_exhaust.html
If no exhaust leaks maybe there's still junk in the carbs, Check the intake boots by spraying carb cleaner and listen for RPM changes.

Offline VirginiaJim

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Re: backfiring?
« Reply #3 on: August 19, 2020, 10:31:41 am »
Could also be sitting for a month and something got gummed up.  Something I don't experience anymore with FI.
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Offline Chrome Megaphone

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Re: backfiring?
« Reply #4 on: August 19, 2020, 10:46:36 am »
If you paid for the carb job take it back.  I would. If the tech didn't soak them long enough and chase the passages with a strand of throttle cable before blowing them out he didn't do it right.

Offline Chrome Megaphone

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Re: backfiring?
« Reply #5 on: August 19, 2020, 10:49:58 am »
Quote
had the carbs rebuilt in August.
Last August?  Sat through the winter?

Offline DC Concours

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Re: backfiring?
« Reply #6 on: August 19, 2020, 11:00:27 am »
I haven't had carbs cause backfiring issues after a long storage period. Just hiccups and low speed rpm issues. Redo the carbs after you eliminate any exhaust problems.

Offline Daytona_Mike

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Re: backfiring?
« Reply #7 on: August 19, 2020, 03:47:57 pm »
One month??... I have had jets blocked from sitting 3 weeks. You may have to dump that fuel ..drain the bowls... and try fresh fuel. Are you adding  a capfull of two stroke oil to each tank of gas? Stabilizer?  Anything? Ethanol free fuel?

If you still have fuel in the tank, you are not lost yet
Most motorcycle problems are caused by the nut that connects the handlebars to the saddle

Offline jim-d

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Re: backfiring?
« Reply #8 on: August 20, 2020, 12:56:26 pm »
I'm done with this bike.  I believe it was severely damaged by leaking carbs.

When I got the carbs back it ran like a top, that was May.

last week I started it up, there was a decided thump, like one cylinder wasn't firing.  made a mental note

last night started it again & things got ugly.  Started backfiring, the thump went away but I stopped for gas & it wouldn't start and run without the enricher on full.  No power in the throttle.   There was a metallic ping when it ran.

So I am tired of this machine and an offering it to anybody who wants it for free.  I live in Marlton NJ, come get it.
If transportation is a problem I will gladly get the sawzall and chop it up into manageable parts for you.

Call me, come get it.


Offline Chrome Megaphone

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Re: backfiring?
« Reply #9 on: August 20, 2020, 01:44:57 pm »
Why are all these free bikes always in the NE? :(

Offline DC Concours

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Re: backfiring?
« Reply #10 on: August 20, 2020, 04:22:42 pm »
Who did your carbs? Were overflow installed? You may have a bent rod.

Don't throw away your bike. It still have lots of valuable parts on it.

Offline gpineau

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Re: backfiring?
« Reply #11 on: August 20, 2020, 04:41:11 pm »
If I lived in NJ I would take you up on it. Lots of good parts still on it. I'm in colorado so I cant.
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Offline DC Concours

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Re: backfiring?
« Reply #12 on: August 20, 2020, 04:45:07 pm »
Me too. If I had a truck i would drive to him. Damn.

Offline jim-d

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Re: backfiring?
« Reply #13 on: August 20, 2020, 05:01:11 pm »
carbs were done by popular person on this board.  thought i was home free.  valve is on run and been leaking for 2 days. nowthe neighbor is complaining about the smell.  i have just had enough.

Offline gpineau

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Re: backfiring?
« Reply #14 on: August 20, 2020, 07:18:27 pm »
So do you think you hydro-locked and bent a rod ?

Bummer.
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