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carbs rebuilt stage 1 now back fireing

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Old 04-13-2010, 08:11 PM
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carbs rebuilt stage 1 now back fireing

I tried to search but nothing found that was clear

ok I bought this vtr. The day I got it the floats were sticking and filling the airbox with fuel. i took it to a honda mechanic (friend off of a local forum). We opened it up and 293.44 later plus a dyno jet stage one kit, petcock rebuil kit. Now it runs strong but back fires alot.

there is a Kand N on the bike soon to be BMC. Staintune high mount cans.

Anyway new fuel in tank. and the only thing wrong now is back fires.

I would really like some help from you guys.

Do I need to change te jets? Burn the Bike? Or re we missing something?

Thanks guys for your help

oh yeah its a 98 hawk
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Old 04-13-2010, 08:19 PM
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Do you know what the setting where for the carbs? Main jet size, pilot jets, needle position, and mixture screw setting? This will help us help you. Also backfires that sound like 50 cals are bad settings, or poor spark, backfires that sound like small puffs usually during decel are most of the time related to the pair system which most of us have removed. So 50 cal backfire?
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Old 04-13-2010, 09:40 PM
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backfires when decelerating? If so, it's probably just the PAIR system doing its job.
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Old 04-14-2010, 02:31 AM
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+1 ^. There is a great write up here:

https://www.superhawkforum.com/forum...ad.php?t=20918

You can get the block off plates here:

https://www.superhawkforum.com/forum...ad.php?t=18515

While you are in there, adjust the TPS:

https://www.superhawkforum.com/forum...ead.php?t=9876

These easy mods made a significant improvement to my bike. Starts right up - one push of the button, no more decel popping.

Oh yea, put in some APEs too, and check the valve clearances, and sync the carbs...



JB

Last edited by residentg; 04-14-2010 at 02:47 AM.
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Old 04-14-2010, 02:32 PM
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Leaking exhaust will also cause exhaust popping - look for telltale black soot at all joints.
Excessively lean jetting will also cause backfiring on throttle over-run.
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Old 04-14-2010, 04:26 PM
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I just went thru the same thing. Dj stage one installed, then would run strong everywhere except small throttle openings. Usually between 3,4k rpm. It would sort of sputter, then backfire thru the carbs. Today I dialed the tps in at 502 ohms. No more backfires! I never thought it would make such s difference, but it did. Maybe try that if you don't already have that done. And while you're in there, rip out that pair system. Great writeup on both in the knowledge base section.
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Old 04-14-2010, 05:28 PM
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sweet guys. I will try your suggestions. Thanks again I will let u know what it does
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Old 04-14-2010, 06:17 PM
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No prob. I don't claim to know near what some of these other guys do, but that sounds so similar to what I dealt with that I had to give my 2 cents. Hope it works for you.
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