RPM's wont come down to idle - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 5 (permalink) Old 05-19-2010, 09:22 AM Thread Starter
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RPM's wont come down to idle

Bought this '03 three weeks ago with less than 700 miles on it. Adjusted idle speed but smells rich, give it some throttle and the RPM hovers @ 1800. Checked vacuum lines, any ideas? Throttle cables/linkage snap back & work fine. Play with the idle adjust wheel some more, give it throttle, same thing

Last edited by newby27; 05-19-2010 at 03:02 PM.
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post #2 of 5 (permalink) Old 05-19-2010, 10:14 AM
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All i know is that the slightest air change in volume due to intake or leak can through that idle off. I didn't replace the oring on the air cleaner (thinking it was such a stupid part) and the bike idled high due to the increased intake. I ordered another oring(20 bucks) oem from ron ayers. Now i am earshaving....so much for the ears and the 20 dollar orings.

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post #3 of 5 (permalink) Old 05-19-2010, 02:54 PM
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lube the lines

Is the throttle sticking or is it coming all the way back to the original position. Might have to adjust the adjust screw down to bring down the rpm's. Just start it and let it get warm. adjust the screw. It's located on the left side of the bike. It's actually a black knob. turn one way if the rpm's go up turn it the other way to where you feel comfortable. Also check out this link on lubing your lines. http://community.cruisercustomizing....177/22960.html

The adjustment screw is on page 26 of the service manual.

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post #4 of 5 (permalink) Old 05-19-2010, 03:23 PM
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Check you air filters,clean, dirty, and if there are any. Try Sea foam, this can help to clean out the carbs. You could have a stuck float. Let us know what you found.

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post #5 of 5 (permalink) Old 05-19-2010, 03:26 PM
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An 03 with 700 miles on it has sat most of its life, which you probably know is bad for a bike. Things get gummed up over any period of time the bike sits. It could be vacuum related, but since you smell fuel, I'm thinking that your choke might be sticking, or the diaphragms could be sticking, or even the floats sticking open some allowing too much fuel being overflowed into the intakes. These are guesses, but it might be worth at least going on a half can of seafoam in your gas for a tank or so and even filling the carbs through the fuel hoses and letting them sit overnight to see if it clears up any varnish.

Ordinarily, when the throttle snaps back solid and the rpms hang up, I would suggest vacuum leaks, but the fuel smell sounds suspicious to me.

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