Throttle response issues - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 2 (permalink) Old 05-31-2012, 06:27 PM Thread Starter
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Unhappy Throttle response issues

Hey guys. I bought my 91 Vulcan 750 about 2 months ago. Prior to that it had been sitting for about 6 months. The carbs were cleaned last year. I replaced the battery, changed plugs/wires, changed oil and oil/air filter. I also installed a cobra exhaust system and coasters. I DID NOT change the jetting when I put the exhaust on. All these changes were made within a week of me buying the bike. It ran fine for close to 1500 miles (when I purchased it had 25xxx) and then last week things went down hill. I went out for a ride one day and out of the blue I had terrible throttle response. It will sit and idle fine. I can rev it up and it sounds a little rough, but no back firing or poor throttle response. But as soon as I get above first gear i have no throttle response until its past 1/4 throttle, then it kicks in like there's nothing wrong. If I hold steady at 1/4 throttle it will die. Anything over 70mph I don't have any response. Keep in mind that it runs fine with the clutch in or sitting in neutral. I've tried running sea foam and Lucas injector cleaner through it but neither of those helped. I don't think it's a jetting issue because jetting doesn't go bad over night. It ran fine until a week ago. Any help will be MUCH appreciated

Last edited by Con707904; 05-31-2012 at 06:29 PM.
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post #2 of 2 (permalink) Old 05-31-2012, 06:53 PM
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Try draining the carbs at the bottom of the carb at the nipple at the bottom. A little allen screw is just above it that lets the fuel flow. Put a little vacuum to the fitting on the left side at the fuek selector to refill the carbs. As some other guys have done, they filled the carbs with sea foam and let them set all night, drained,refilled the carbs with gas and tried the bike again. Try again if it does not work the first time.

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