A New Beginning - Still Having Problems - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
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post #1 of 6 (permalink) Old 07-31-2009, 03:53 AM Thread Starter
 
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A New Beginning - Still Having Problems

Luckily I haven't spent a TON of money but the problems are still there. I'm going to start all over and follow everyone suggestions to a T.

Bike starts fine from cold. Using the choke I lose RPMs. Bike will not idle. Wants to gently die. I up the idle and pretty soon it's idling VERY high and I put it back to normal - then it wants to gently die again - I can't find the balance. Bike drives fine for a while - plenty of power. If I take a short ride and park it then start it up again shortly after it seems to still run ok. If I'm out for... 10ish minutes the bike will starts to sputter in RPMs. Seems like after 3000 it's all over the dial and I have to rev it to 5+ and ease the clutch in to make it run normal. Minimal backfire/misses (can't tell the difference). Sometimes when I pull the clutch in I see the RPM SHOOT down and ALMOST die if it weren't for my last minute throttle. I also notice that it will idle at 500RPM but I never let it idle long because I know it will die. After I cut then engine then try to restart around this time it's usually MUCH more difficult to start - I have to open the throttle quite a bit and it just barely turns over. At this point the choke MAY give more RPMs than normal (depending on where my idle screw is I guess). The bike still will not idle at this point. I get discouraged - I drive it home. And normally after a few rides with this typical pattern the battery will run itself out. Man... I DO NOT want to admit defeat!

Heres What I've Done:
-New petcock kit
-Cleaned Carbs twice
-Replaced Side Diaphragms for Carb
-Synched the carbs (using handmade manometer and regular motor oil - adjusting as I went on the road thinking that would help - god knows where it's at now)
-Air Screws Out 3x 360deg
-Vent Hose attached to Right ear Upper Side
-New Vacuum Hose to the Petcock
-Seafoam
-Seafoam
-Seafoam
-Carb Dryer
-Engine Flush
-New Oil/Filter
-New Coolant

I'm ready to rock - I'll do anything.

Last edited by SyntaxJO; 07-31-2009 at 04:00 AM.
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post #2 of 6 (permalink) Old 07-31-2009, 06:53 AM
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I don't know much about this, but maybe you have a weak ground from the battery...or even a flaky battery.

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post #3 of 6 (permalink) Old 07-31-2009, 07:24 AM
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Sounds like a more extreme versions of what I am going through. You may have other issues but what I am working on is really getting my fuel intake system clean, clean, clean.

Is there rust in your tank? Has there ever been? Mine has been run with rusty tanks in the past and every time I think I have it cleaned the problem returns and I am told of some other area I need to clean. Most recently I let the floats run dry by running w/ the petcock on off and all my problems came back plus some. It has been surmised that I knocked more crud out of crannies by doing this, maybe even the fuel lines themselves.

So this weekend I am taking off and cleaning the carbs again. Bought actual carb dip this time. Going to drain and rinse the tank thoroughly and get completely new gas. Rebuild and clean petcock. Replace all fuel and vacuum lines. Install inline fuel filters.

Your situation does sound like it could have an electrical component as well, but IMO those are harder to diagnose. I would make sure your fuel intake is clean as a whistle and then see what it does. If nothing else you eliminate that from the equation and the symptoms might be more diagnosable.

As far as that goes, going from my experience on other bikes, what you're describing could come from a bad battery and/or CDI.


Current VN: 03 VN1600A

Past VNs: 92 VN750A, 98 VN1500A

Future VN: 94/97 VN1500A basketcase/bobber
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post #4 of 6 (permalink) Old 07-31-2009, 08:15 AM
 
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This is what I would do....first to find out what system is causing the problem (fuel, electrical) remove the gas tank and pour the gas into a container, to see if you have rust and gunk in the gas, if so this is the first system to suspect.Clean the tank, including the petcock. You may even have to go into the carbs. If your fuel is clean then test your electrical system, with the bike running, hook a volt meter set to 50volts DC to your battery, rev the engin to around 4000rpm, you should see the needle move or if digital see it go from 12volts to around 14volts. Try this and let us know how it checks out and we can try to help you further.I guess I should have read a little further to see what you have already done. Looks like you have been working on the fuel side of things, now check the electrical, a bad battery or charging system can cause some of the things you are seeing.

Last edited by CapHAB; 07-31-2009 at 08:21 AM.
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post #5 of 6 (permalink) Old 07-31-2009, 05:52 PM
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Good suggestions above. Check all your grounds and connections. Pull your plugs and check condition. Are they wet, black, brown, white??? It really sounds like carb and fuel delivery, but sometimes other things can send you in the wrong direction. You gotta look for clues and then try to focus on what might be going on. Keep up the chatter about what you are doing and finding and there will be support for you here! Good luck!

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Kyle, TX VN750.com member #707 VROC#19556
2002 VN1500 Classic
Spline Lube Procedure, with photos, R/R Relocation and Coil Mod
Rusty Tank Cleaning!
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post #6 of 6 (permalink) Old 07-31-2009, 06:11 PM
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Can you take a compression test of the cylinders? How old is the bike or how many miles on the speedo. I had a car once that had a chipped valve seat and it would not idle at all unless you kept it at a high RPM. Just something else to look at, may not be of help. Hope you find the trouble soon, before you really do get discouraged.

2004 25,500 miles
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