RPM's 4000 at idle
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RPM's 4000 at idle
Hi All, New bike owner '90 Sportster 1200. Bought the bike in non running condition. Replaced the coil and ignition sensor (Ultima programable kit 53-660) and it fired right up. RPM's at idle was 4000. Backed off on the idle screw on the carburetor per service manual counterclockwise (maybe 5 full turns) did not make a difference. Also..there is a thumb screw at the top of the carb with a tube coming off that is attached to the bottom of the carb(thumb screw is tightened down clockwise) there is another tube same diameter attached at one end and just is hanging down unattached at the bottom of the frame. Thinking maybe a detached vacuum line from somewhere. Didn't want to let the engine run for any length of time. Maybe 10 sec intervals between backing the idle screw out. I believe the carb was cleaned by previous owner. Think the bike was sitting for a year or so. Any ideas. Thanks V
Last edited by Vza; 06-30-2024 at 10:24 PM.
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smitty901 (07-01-2024)
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It's an S&S super E carb with some extra lines and a
thumbscrew thingy at the top. I think its some sort of mod. I supposedly adjusted the carb to factory settings and now idles between 3000-5000 rpms. Think I'll try and adjust the throttle free play next. Question...I assume it's not good to run it at that RPM for any length of time. I'll get it started and try n push the choke in...(they call it something else richness adjuster or something) the rpms will drop then it stalls. It's sort of all over the place between 3000 and 5000rpms. The exhaust gets super hot very quickly. Ugh...any thoughts?V
Last edited by Vza; 07-01-2024 at 09:48 PM.
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pgreer (07-02-2024)
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Goose_NC (07-11-2024),
luckiestiff (07-02-2024)
#9
That carb has a (thingy) Thunderjet installed, which is essentially an addition / addon fuel circuit enhancement to the carb. In terms of the choke, it's an enrichner for starting the engine cold, but should be turned off once the engine has started or it will flood the engine with too much fuel anf foul the plugs.
Can you look in the throat of the cab and see if thg throttle plate is fully closed? Try the cable adjustment, or even remove the throttle cable to eliminate that being the problem with the high idle.
Paul
Can you look in the throat of the cab and see if thg throttle plate is fully closed? Try the cable adjustment, or even remove the throttle cable to eliminate that being the problem with the high idle.
Paul
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Goose_NC (07-11-2024)
#10
http://www.harley-performance.com/s-...b-upgrade.html
they are similar but you need to know the difference. da vinci goes a few steps ahead.
they are similar but you need to know the difference. da vinci goes a few steps ahead.