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Discussion Starter · #1 ·
new to forum. need help. I have a 99 RoadKing-carb model. Bought it in july 05 with 33,000 miles. only mods are a k&n open filter and jetting with thunderheader slipons with the factory headers. My problem is when i let of the throttle to shift it will backfire like a 12 guage, especially when cold. not so much when warm. also when idling at a stop it will pickup speed and then drop rpm almost to a lope. i have set the idle to be high around 950-1050 like manual says.looked for vaccuum leaks on manifold around all seals inlcuding the MAP sensor on the manifold. I have made sure the throttle and idle cables are adjusted properly per manual. set air screw in till stumbles then back out till smoothest high idle. just does not seem to want to idle smoothly at a constant rpm. iknow these bike jump around at idle and this being rubber mounted it jumps quite a bit. it just seems like it will pickup idle speed and then almost stall till you give it gas then it picks up again. checked plugs and they are closer to being rich but not overly black in color. just want to be able to go down the road and not sound like a cannon when i shift and not stall out and every stop.


sorry long winded.

thanks:whistle:
 

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Congrats on the Road King! Sounds like you need to go thru the carb, check the torque on the front motor mount and snug up all the fittings on the exhaust system. When going thru the carb make sure you have the correct jets, as some people through larger jets in to solve a air leak. :chopper:
 

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Discussion Starter · #3 ·
Well..............found out the problem. It seems the vacuum operated petcock went south on me. I cleaned the carb out when I first got the bike. Kept hearing a slight hissing sound from under the tank when idling every once in a while. well decided to drain tank and remove petcock to change filter, thought that might be clogged. well i was using my mighty-vac brake bleeder systme to apply vacuum to the valve so it would drain. every time i pumped the handle just a little fuel would come out and i kept hearing air leaking from under the tank. WELL after fingering every hole on the fuel valve I found it had a port on the bottom, put my finger over it a holy cow did the fuel flow when i hit the vacuum trigger. well i bought a pingel non-vacuum petcock today and will put that in and cap off the carb. no more air leaks
 

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Keep in mind your carb does not have a fuel overflow on the float bowl. By putting on a pingle petcock, there is a possibility that fuel could leak past the float needle, over fill the bowl and drain into the motor. Either, always turn it off when you stop, or get an older float bowl with a drain and overflow on it.
I did the later.
 
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