What are the common causes of a backfire on a Hawk?
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running to rich but when is it doing it???
durring acceleration or deceleration1988 & 1991 hawkgt, 2005 rc51 -
Mine does it on deceleration, what does that indicate?Originally Posted by jaysun0neDamn right it's a Hawk GTComment
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some slight backfire pops are normal and nothing to worry about. for severe cases you should maybe fit new anti-backfire valves (little round diaphrams( THAT SCREW INTO SIDE OF CARBS).[/u]"It's only getting worse."
MY rides: '97 VFR750, '90 Red Hawk, '88 Blue/Black Hawk, '86 RWB VFR700 (3), '86 Yamaha Radian, '90 VTR250, '89 VTR250 (2), '73 CB125, '66 Yamaha YL-1
Sold: '86 FJ1200, '92 ZX-7, '90 Radian, '73 CB750, '89 all-white Hawk, '88 blue Hawk, '86 FZ600, '86 Yam Fazer 700 , '89 VTR250, '87 VFR700F2, '86 VFR700F.Comment
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Well, it was running fine with the occasional backfire on deceleration. However, today after about 10 mi. it started backfiring primarily on decelaration but also some during acceleration. When I got it home it did so at idle and after a rev.Comment
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Mine does the same.....I have a supertrapp should I try to lean it out? My also backfires at about 6 grand and runs rough from there up????On Hawk rebuild number 3...Comment
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I have a Supertrapp and mine does a mean little pop-pop-pop coming down from 4 or 5k rpms while engine breaking. Every great once and a while, I get a pop after a cold start. But she needs a tune up anyway.“Freedom is something that dies unless it's used”
- Hunter S. Thompson
1989 Hawk GT - As a whole, it is gone, but it now lives vicariously as a small part of several other Hawks on this website.
1997 VFR 750 - D&D exhaustComment
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It also depends if it's backfiring out the carbs or exhaust. Mine sometimes backfires out the carbs if the bike's still a little cold and i blip the throttle. It only started doing it after i leaned up the carb mixture... but the increase in power was worth it so I'm not too bothered. When she's hot she runs sweetly!
An exhaust backfire on deceleration could be caused by an air leak at the header pipes or intake manifold, causing a lean mixture.
High speed backfires usually just mean you need a tune up... dirty plugs, air filter, fuel filter. If you've got an aftermarket exhaust or air filter you might want to check the jetting.
Do a plug chop and see how she's running.
"Worry never robs tomorrow of its sorrow, it only saps today of its joy."Comment
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Check the exhaust stud nuts.
-Acouple of times for me, even using locktite, the nuts will vibrate loose (or fall off) and the header will loosen off, causing the lean backfire. I think a common situation with Hawks.-I'm sorry....I did not know she was your sister.
-If Buckleys cold mixture went rancid......how would anybody know????
-Dont piss off the quiet guy with the chain saw.Comment
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Originally Posted by SaffaChrisIt also depends if it's backfiring out the carbs or exhaust. Mine sometimes backfires out the carbs if the bike's still a little cold and i blip the throttle. It only started doing it after i leaned up the carb mixture... but the increase in power was worth it so I'm not too bothered. When she's hot she runs sweetly!
Mine does the same thing Chris...but i havent messed with the mixture of the carbs...theyre stock. How would i go about richening up the mixture with stock carbs..even though it shouldnt have changed itself in the first place? Could there be some crap clogging them a little somewhere? Or possibly sync ing them!!! AH HAH i just had a realization...i never synced my carbs after i had em apart for cleaning....this is most likely my dumbass fault afterall!1989 Hawk GtComment
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Is your airbox and exhaust stock? Having a more freeflowing system leans out the mixture. If it's all stock there's the possibility that you have an air leak somewhere causing more air getting in the carbs. How clean is your fuel filter? If that is even slightly clogged you're gonna get less fuel in the mixture.Mine does the same thing Chris...but i havent messed with the mixture of the carbs...theyre stock. How would i go about richening up the mixture with stock carbs..even though it shouldnt have changed itself in the first place? Could there be some crap clogging them a little somewhere? Or possibly sync ing them!!! AH HAH i just had a realization...i never synced my carbs after i had em apart for cleaning....this is most likely my dumbass fault afterall!
Do a plug chop before taking anything apart or messing with mixtures. Do it at 3 different rev ranges: idle, 3-5k rpm, 6-8k rpm. Run the bike(ride it, don't just rev it) at the desired rpm and hit the kill switch, then take a plug out of each cylinder and see how it looks. It can tell you quite a lot about your mixture."Worry never robs tomorrow of its sorrow, it only saps today of its joy."Comment
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yeah the filter is probly in need of replacing too....its about the only thing that i didnt replace or clean..1989 Hawk GtComment
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Re: Backfire
Originally Posted by jaybird
running too rich.
running too lean.
timing off or misfiring.
exhaust leak
when a bike starts doing it out of nowhere, with no parts changed, its usually just an exhaust leak.
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