leaky carb, wont idle - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 11 (permalink) Old 04-15-2012, 04:47 PM Thread Starter
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leaky carb, wont idle

As above, the leaky carb is for the front cylinder. When the bike dies there is black smoke out the tailpipe. I'm real new to this, I just got the bike a couple of days ago and it was like this when I bought it. This sounds like a stuck or bad float valve to me. In another thread it was suggested to drain the float bowl and pour seafoam right down the gas line and let it soak. I just did that today and will let it soak for a day or so. I took the tank off to make it easier to get to the gas lines. I was also hoping to be able to see more of the carbs but there is this huge plastic thing in the way (airbox? surge tank?). I can see an advantage to shaving the ears now, more room. I swear if I have to pull the carbs I'll do a shave while I'm at it.
Another thing Ive noticed is that little flexible thing that lets you adjust the idle speed is broken. I have no idea where to find another one, or even if adjusting the idle is something I need to do often.
Oh, and its a 95 VN750. I paid a grand for it, so if I have to put another grand into it then I I'm still right at the retail book value.
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post #2 of 11 (permalink) Old 04-15-2012, 04:58 PM
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I would let the carbs soak overnight and see if it improves.

Pulling the carbs to clean them are a pain, so hopefully soaking them will unstick the float and clean out whatever is causing the problem.

Not sure if the idle adjust knob is broken, or if you need a new cable, but you really don't need to adjust it once you have it running right. You can look on eBay for those or maybe someone here has a spare.

I am sure one of the more experienced guys will be along to give you some sound advice on the carbs.

Good luck!
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post #3 of 11 (permalink) Old 04-15-2012, 07:46 PM
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the big black box is the air duct. as for the carbs leaking, it could be a stuck float, or what i just dealt with on mine... a pin hole in the float allowing the float to fill up with gas. I have an extra float and idle adjustment screw if you need to go that rout.
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post #4 of 11 (permalink) Old 04-15-2012, 10:09 PM Thread Starter
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Quote:
Originally Posted by slimvulcanrider View Post
the big black box is the air duct. as for the carbs leaking, it could be a stuck float, or what i just dealt with on mine... a pin hole in the float allowing the float to fill up with gas. I have an extra float and idle adjustment screw if you need to go that rout.
Ok cool. That answers one thing I was wondering; what type of float it used. Many years ago I spent some time as a small engine mechanic and saw some solid foam floats but most were hollow like you describe. I once saw one that was crushed by water freezing in the float bowl. Hopefully the Seafoam works its magic or I'll end up having a mechanical adventure much sooner than I had planned on.
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post #5 of 11 (permalink) Old 04-16-2012, 01:27 AM
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they use plastic floats...
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post #6 of 11 (permalink) Old 04-16-2012, 06:49 PM Thread Starter
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PROGRESS!! The seafoam soak didn't work, but I read about shooting Gumout through the drain hole also. I couldn't get the tube into the drain hole, so I disconnected the fuel line again and shot it in there until the fuel line was full. I let it soak for about 15 minutes and then got it started. It idled ok at about 800rpm. Took it out for a spin and it no longer stalls on a downshift. However it won't idle at 800 when good and warm so I need to increase the idle speed. This is going to be a pain with the cable broken but I will manage it somehow, I just need to find a really small pair of channel lock or something to get in there to turn it.
On another note, it didn't seem to have the power that it did before. I fiddled with the pilot screws while trying to get it to idle, and had them turned out 2 turns when I rode it. I've since backed them out another turn. Where is a good place to start when setting them? Also, since it's called a pilot screw instead of an idle mixture screw, I'm guessing it sets the mix across the throttle range?

4/12/12 1st bike ever! 95 VN 750 13k
New plug wires
Iridiums
Coil relay mod
MCCT mod
Marbled
EPA stuff removed
Rear signals shaved
Shinko 170-110 oversized tourmaster tires
Splines lubed
Front signals relocated.
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post #7 of 11 (permalink) Old 04-17-2012, 08:18 AM
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2 1/2 turns is a good starting point, idle 1100rpm
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post #8 of 11 (permalink) Old 04-17-2012, 07:09 PM Thread Starter
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Good, then I'mANDY right where I need to be. Took it for a little ride and when I got back the float was stuck again. More gumout. I figure I'll either get it all or melt down the rubber parts in which case I'm in for a rebuild anyway.

Addendum: The gumout worked again but I Torre a hike in a fuel line taking it off the tank. Maybe disintegrating fuel lines were my problem all along...

4/12/12 1st bike ever! 95 VN 750 13k
New plug wires
Iridiums
Coil relay mod
MCCT mod
Marbled
EPA stuff removed
Rear signals shaved
Shinko 170-110 oversized tourmaster tires
Splines lubed
Front signals relocated.

Last edited by skyboxer; 04-17-2012 at 11:16 PM.
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post #9 of 11 (permalink) Old 04-17-2012, 11:53 PM
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bad fuel lines coulda been the culprit
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post #10 of 11 (permalink) Old 04-21-2012, 06:37 PM
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Sounds like mine, if you drain the bowls it starts and runs fine.. then one cylinder loads up. If i reve it comes back but it wont idle. I was going to tear the carbs out.. but right now a few hours at the actual "how the heck does it come out" stage Im leaning to something like this... I have read several threads on carb removal but didint expect it to be as bad as it is.. I would rather have teeth pulled.. Getting the boot between the carb and airbox (that is called Purge resivoiur in my manual?) 2 hours of wiggling and moveing and pulling and tyring not to ripp it.. Im going to try some cleaner...damn...
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