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Discussion Starter #1
I've got a 94 with about 12,000 miles on it. I have been fighting what I always thought were fuel issues. The bike usually starts fine but then idols weird, doesn't increase in rpms and wants to die even with the choke left on. To keep it running I have to keep the rpms up with the throttle. These are thing that I have done to try and get rid of the problem

1. Sea Foam
2. New sparkplugs, gapping and cleaning sparkplugs.
3. Pulled the carbs and cleaned them without splitting.
4. Along with three, drained tank, removed petcock and cleaned screen.
5. New air filters.

After the carb pull and tank cleaning it started right up and ran like a different bike. It sat for two weeks and Saturday it was back to the same old thing. Sunday it started right up but still idled slow. while it was trying to die I removed the front plug wires and realized that the performance did not change, reattached them. Removed one rear wire and performance went down, reattached. Shut the choke off and the bike died. The left pipe for the rear cylinder burned my fingertips and the right or rear one was cold. I removed the plugs and found that the front ones were wet or fouled and the rear ones looked ok.

Right now I have the front and side covers off and am trying to troubleshoot for an ignition problem. What I can't figure out is why my problem is intermittent. If I had the money I think I'd be looking for a replacement.

I have the Kaw Manuel but none of the ohm readings I'm getting on different components match the book. Does the Kaw voltmeter really get the reading in the book?

Any trouble shooting advice you can give would be greatly appreciated.
 

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Some folks have trouble with the gas take breather hose. Gets clogged and fuel can't flow.

DT
 

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and the Adventure Cycle
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This may be a dumb question, but gotta ask to be sure..... have you tried adjusting the idle knob?
Might not hurt to get the carbs sync'd even though ya didn't split 'em.
A home made manometer to check them is easy to make.
 

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Linkmeister Supreme
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It sounds like you are losing spark to the front cylinder when the ignition components warm up.

Pull the front plugs and check for spark when cold. From your description, it should have spark. Reinstall plugs and warm up until front cylinder cuts out. Check for spark again.

Also check resistance of the pick-up coils, and the ignition coils when cold and again when they are warmed to at least 70*F, or when the front cylinder cuts out.
Specs are in my Clymers manual, and I assume in the Kawi manual too. Depending on what you find, there are mods that can be done to one or both to strengthen the spark.

The service manual says a special Kawi ohm meter must be used to test the ignitor unit. Any other will give unreliable readings. For this reason the ignitor is usually only able to be tested by replacing it with a new, or known good one.

Here is a link that may help you. There are a couple of other links in that one too.
http://www.vn750.com/forum/showthread.php?t=7946&highlight=ignition+pickup+coil
 

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Discussion Starter #5
Hyperbuzzin, in the past three or four years dealing with this intermittent problem, I have used the idle adjustment knob to up the rpms, so that when pulling up to a stop I can use both brakes without stalling out.

Gordon, thanks for the attached links. I've read them over this morning and plan on doing more testing to find out what's at fault. I always try to expect the worst. Maybe it's just a short. It sound like when the electronic parts go they just stop working. My problem goes away for a while then comes back.
 

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I ran into something like that a few yrs ago.
Check that you have power to both coils, my back one was getting power but front wasn't getting anything. Found out it was the JB. The PO had spilled acid and it shorted out the JB. Idled OK on the rear but no power. Front cold rear good n warm.
 

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'03 VN750 "Rosie"
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I ran into something like that a few yrs ago.
Check that you have power to both coils, my back one was getting power but front wasn't getting anything. Found out it was the JB. The PO had spilled acid and it shorted out the JB. Idled OK on the rear but no power. Front cold rear good n warm.
For the rest of us amateurs, what is a JB and a PO? Junction Box?
 

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Junction Box
Previous Owner
 

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Discussion Starter #9
I plugged all of the electronic components back in to check for a spark. Both plugs on the front cylinder spark and appear as strong as the back. I cleaned the front plugs and then started the bike. It starts right up but only the back one is firing. Hyperbuzzin mentioned syncing the carbs. I think I'll try that next. I just don't understand why it is an intermittent problem.
 

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Discussion Starter #10
Before screwing with the carbs i decided to go ahead and start it up again. Fired right up with only the back one running. I upped the throttle a little at a time and at around 3000rpm the front cylinder kicked in and it evened out. I shut it down when grayish black smoke started shooting out of the pipes. To me it looked like both. I was going to check the compression but I don't have the right fitting for my tester. I'm hoping the smoke was because it wasn't warmed up enough. What do you guys think?
 

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Linkmeister Supreme
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Before screwing with the carbs i decided to go ahead and start it up again. Fired right up with only the back one running. I upped the throttle a little at a time and at around 3000rpm the front cylinder kicked in and it evened out. I shut it down when grayish black smoke started shooting out of the pipes. To me it looked like both. I was going to check the compression but I don't have the right fitting for my tester. I'm hoping the smoke was because it wasn't warmed up enough. What do you guys think?
The spark must be able to jump a 1/4" gap in the open in order to be able to create a spark in a 0.030" gap under compession.
http://www.dansmc.com/troubleshooting3.htm

Maybe make a spark tester by bending the ground electrode out straight on a new plug as suggested in the link above.

I`m thinking the front ignition coil needs a full 12 volts that it may not be getting, as per fergy`s coil mod:
http://pages.tstar.net/~fergy/writeups/coil_relay_mod.html
 

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Discussion Starter #12
I almost did that when I got home from work today. I read that part of the manual at lunch and that's why I was going to do a compression check. I didn't realize the spark had to be able to jump that far. I'm going to charge up the battery, get a new spark plug and see if the spark jumps that far. I hope the smoke was a one time deal.
 

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mine did the exact same thing on rear and my best guess was that wasn't getting fuel to the rear. suddenly got fuel, smoked like crazy then cleared up evened out and ran great rest of the time i had it. when it was sold, acted up again but finally straightened up as the buyer rode off on it.
 

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what color was the smoke? also is your exhaust have alot of humidity coming out of it? if your compresion is indeed low you could have a bloawn head gasket.
 

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Discussion Starter #15
The smoke was on the blackish side. I still need to pickup an adapter for the compresion check.
 

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Discussion Starter #17
The right side from the front.
 

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Discussion Starter #18
The compression checks out good. both cylinders are in the same range. While I am charging the battery up, after all the testing I went ahead and drained the float bowl on the front carb and filled it with a cleaner.
 

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Discussion Starter #19
After draining the carb cleaner out, and charging the battery it fired right up and idled without the choke set. Both cylinders are now firing. As you can tell I usually expect the worst. I'm assuming this problem will be back. If it does I'm going straight to the left carb.

Thanks for all of the advice and help. Hopefully my troubleshooting skills will improve.
 

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After draining the carb cleaner out, and charging the battery it fired right up and idled without the choke set. Both cylinders are now firing. As you can tell I usually expect the worst. I'm assuming this problem will be back. If it does I'm going straight to the left carb.

Thanks for all of the advice and help. Hopefully my troubleshooting skills will improve.
Seafoam the tank...about 1/4 to 1/2 cup and drive it like you stole it for a while..this should help clear up the dirty carbs...I have mine pulled right now...its amasing how dirty they were... but mine hadnt been off since 1992...LOL
 
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