Lagging throttle response - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 7 (permalink) Old 10-19-2010, 11:11 AM Thread Starter
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Lagging throttle response

Ok on my 93 750 after it came back from the shop from getting the carbs rebuilt the throttle is slow to respond. The throttle blades themselves are moving just fine. My mechanic took off the old throttle cables and only replaced one of them. I dont know why they only put one on and I was wondering if that could cause the throttle to respond slowly. Also the hose that used to go to the back of the air box on the right hand side is no longer plugged into the back of the air box and has been replaced with a new hose that I do not think will go into the back of the air box anymore. I know my coils are getting weak and I have new ones on order and the timing magnets have been moved to where the gap is less. I was also wondering if these magnets could be getting weak and need to be replaced.
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post #2 of 7 (permalink) Old 10-19-2010, 04:00 PM
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I'd be looking for a new mechanic. Were the old cables bad, or just need to be lubed? The dual cable system is for safety. If the lone cable breaks at WOT, you may have a problem. But not if you have the second cable. And if the throttle spring is weak (hey it's 17 years old) that would account for the slow throttle response. Put those two together and you have a recipe for an accident.

If that hose isn't protected from air flow, the bike's gonna run crappy at speed. Why didn't he put it back? You paid him to do it right, didn't ya?

Can't help you with the other stuff, but someone will.

I'm keepin' all the left over parts. I'm gonna use 'em to build another bike!
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post #3 of 7 (permalink) Old 10-20-2010, 04:37 PM
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X2 on flight's response

Howdo you know your coil is week, the pickup coils either work or don't work, If you are getting week spark, I would look at replaceing the ignition wires, and rigging up a relay to supply the coils with full battery voltage
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post #4 of 7 (permalink) Old 10-21-2010, 04:06 PM Thread Starter
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I know that the coils are weak because as they get hot the spark gets weaker. And as far as the mechanic goes I really dont think they know what they are doing. The bike only lags when it is under 3000 rpm everything above that and the bike responds normal. I also rebuilt the timing chain tensioner and it helped some. This bike is beginning to be a real pain. I dont think it is the throttle spring because the throttle springs back quick as hell. It is more like the motor is bogging down under 3000 rpm but once it gets above that it flys like a rocket.
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post #5 of 7 (permalink) Old 10-21-2010, 04:06 PM Thread Starter
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Oh and I replaced the coils today and no more weak spark as the bike gets hotter.
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post #6 of 7 (permalink) Old 10-21-2010, 07:54 PM
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good deal... doesbattery voltage drop as the bike gets warmer?
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post #7 of 7 (permalink) Old 10-26-2010, 05:08 PM Thread Starter
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No the voltage doesnt drop but I figured out what was causing the lagging throttle. It was old gas or bad gas because the gas I drained out of the bike had a almost dark yellow tint to it. Now that I have new gas in it the bike runs fine. Also I started using the stabil ethonal treatment that is in the marine section at walmart and both my 93 and my 02 have started running 100% better.
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