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carb problem

Old 06-02-2011, 11:36 PM
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carb problem

I have a 99 superhawk with 10k miles that was getting a lean misfire when i bought it. it was also idleing really high. the previous owner had just put on jardine slip ons but it was too lean to be attributed just to that. i installed a dynojet jet kit and looked for any vacuum leaks while it was apart. put everything back together and the lean misfire is gone but now it won't run right. upon startup with the choke off it will run normal (at 1300 rpms) for about 20 seconds then the idle falls and the bike stalls. I can't set the idle properly because of this problem but it seems like the screw is already turned in too far because when i put it all back together i started with a base idle screw setting where i eyeballed a slight gap on the throttle plates. it wouldn't idle so i had to turn the screw in probably two turns just to get it to idle so the throttle plates are probably open too far already. the jet kit was installed per the instructions so that's not the problem. Anyone have any ideas? also the choke lever is operating as it should.
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Old 06-03-2011, 12:10 AM
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Are you talking about the idle adjustment thumb screw on the right-hand side of the carbs, or the sync screw on the left hand side?

Not sure how much effect this would have, but what are your idle fuel screws set at? These are the two "d" shaped screws right next to each carb bowl. If they haven't been touched, they may still have a cover that was put on by the factory that you have to remove.
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Old 06-03-2011, 07:21 AM
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i'm definitely talking about the idle screw. i set the fuel mixture screws as per the dynojet instructions. After sleeping on it i think i may have figured it out. The pilot jets could be clogged so the idle has to be turned way up to bypass the circuit. I should have cleaned them when they were all apart before, that's what i get for trying to save time. Guess I'll pull the carbs when i get home and clean them and see what happens.
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Old 06-03-2011, 09:17 AM
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That sounds reasonable. I had a hard time getting my idle to work correctly when my carbs were way out of sync, so I'd look into that too. I had disassembled them to clean them, and in the process I had completely unscrewed the carb sync screw (which is located on the left side of the rear carb body) and forgot that I had done this. Once I turned it about half way in, I could get the carbs to function enough to get the idle working...

It may be completely unrelated, in which case you just got a story about my troubleshooting and an extra post count for me
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