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Old 09-10-2009, 07:44 AM   #1
duneswatter
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Default 91 nighthawk question

i am having a problem with my bike, it was sitting for about 3 months and it was running great when i stopped riding it, now it won't idle or start unless the choke is on, and even if i let it warm up, it still won't start or idle unless the choke is on, at least half choke. something else that throws me off, is that if you try to give it gas, it will bog down and die, but if you feather the throttle past 3000 it runs smooth, and then if you are holding it at about 3-4000, and you turn off the choke, it will die, no matter how gas you try and give it. i am completely clueless at to what is going on, maybe i am overlooking something simple, but i can't figure out what, i put fresh gas in, changed the plugs and the oil, other than that, i have not really done anything to the bike, does anyone have any thoughts as to what might be causing this problem, any and all help is appreciated
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Old 09-10-2009, 07:52 AM   #2
longride
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The jets in your carbs are clogged. You need to take them off the bike, disassemble and clean them and put them back on and synch them up. Not a huge job if you know what you are doing, but if you don't know how then bring it to someone that does. If you bring it to a shop, it will cost you $500 to $700 bucks for the job.
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Old 09-10-2009, 07:57 AM   #3
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Slow jets or "idle jets" as they're known - are plugged up. Nothing doing but to pull the carbs off, pull 'em apart, and use a strand of copper wire and spray carb-cleaner on those jets. Hold 'em up to a light to confirm they're clear.

Wear eye protection, and DON'T use the spray on anything rubber (causes it to swell and stretch).

Spray it through EVERY orifice in the carb, and if the spray doesn't come out another orifice - it's plugged.

Pay attention to how it all came apart - take pics (nowadays with about a zillion digital cams everywhere including 19 out of 20 cell phones, NOBODY has an excuse not to).

I would also empty this tank of fuel, and check to make certain the tank is clean. Use stabilizer in the future; especially if the bike isn't ridden regularly.
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Old 09-10-2009, 08:02 AM   #4
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sounds good, i guess i will give that a whirl, i thank you for your time in reading and replying,
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Old 09-10-2009, 08:04 AM   #5
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another thing real quick, anytime i pull the carbs off the synch has to be redone correct?
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Old 09-10-2009, 08:14 AM   #6
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Quote:
Originally Posted by duneswatter View Post
another thing real quick, anytime i pull the carbs off the synch has to be redone correct?
I would synch them anytime any change is made.
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Old 09-10-2009, 08:15 AM   #7
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I'm thinking the pilots are plugged also.
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Old 09-10-2009, 08:17 AM   #8
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Quote:
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another thing real quick, anytime i pull the carbs off the synch has to be redone correct?
Not if you don't mess with the cable adjusters. But it's a good idea to check it anyhow. A special gauge for the job isn't much $. And you can use it forever.
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Old 09-10-2009, 09:49 AM   #9
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where can i get that special gauge from? i assume you are referring to the vaccuum gauge for adjustment of the carbs right?
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Old 09-10-2009, 10:02 AM   #10
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where can i get that special gauge from? i assume you are referring to the vaccuum gauge for adjustment of the carbs right?
Accessory shops and online bike stores have them. Google is your friend.
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