Throttle Adjustment Screw - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 2 (permalink) Old 10-22-2011, 02:13 AM Thread Starter
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Throttle Adjustment Screw

Hi All,

I'm a new Vulcan owner, having purchased a V 750 just a couple weeks ago. Still learning and still trying to translate some of the stuff I see on here.

So here's my problem:

I found that the bike would idle a little bit below 1000 rpm while sitting at lights, (what's a good idling range? 1250?) so I thought I could fix it by adjusting the idling rpm up. Not so. It seems that the effect usually took a few minutes to kick in after I had turned the screw. Thus I had the bike die on me a couple times at lights, or have accidentally scared pedestrians because it's chugging away at 3000-4000 rpm while I'm sitting still. Not long after, the throttle got stuck on me and I had to use the engine kill switch. This all happened over a couple days.

I'm thinking that I may have played around with the throttle adjust screw too much while sitting at lights, and that it may have knocked the sychronization between the throttle and carburetors out of tune.

So, should I just never touch the throttle adjustment screw once it's fixed, or could it be something else? I'm rather frustrated with this jumping-bean rpm problem because it kicked in in the middle of my skills test today.

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post #2 of 2 (permalink) Old 10-22-2011, 07:29 AM
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Rider in the Light,

First, the recommended idle speed for our bikes is 1100 rpm +/- 50.

Now got at few questions to you and i mean no harm with them, are you sure your are applying and turning off the "choke" correctly? To engage the enrichment circuit the pulled as far as it will go toward the rear tire, and pushed toward the front tire to disengage.

Also when you go to start your bike, you will most likely need to leave the choke on to some degree, for a few minutes. This gives the cold engine the extra fuel that it needs to keep going. If you are taking the choke off too soon, and using the idle adjuster to regulate engine speed, that could be a cause for your problem. So make sure next time you got the bike going, that you warm it up fully, prior to playing with that adjuster screw.

Socond thing that pops into my mind is a carb problem. Possibly an air leak, or something that cause the bike to run lean. Check the intake hoses for cracks (easy way is to spray carb cleaner all around the boots and see if idle speed goes down, if it does you have an air leak).

Just some thoughts, i am by no means an expert, you have come to the right place and i am sure that someone with more power than me upstairs will be by soon to help.

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