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Jackie Chan Stunt Double
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21 Posts
Discussion Starter #1
Kind of at a loss here...hopefully one of you has some insight into what's wrong. I was riding yesterday, bike running great, down the interstate doing about 65-70mph. Fuel gauge reading just off the "F" and which would be correct as I have only gone about 65 miles since fill up. Out of nowhere, she starts stumbling a little, like the beginning stages of running out of gas, or when the battery cables are not tight. But it is intermittent, as she bogs a little, then picks up and runs right a few seconds, then it happens again. This progresses in the span of about a minute into full blown "bike died" as I am pulling onto the shoulder. I open the fuel tank, and the tank is indeed almost full. I try to restart and she turns over fine, but no start. Switch it to reserve, same result. Put it back to the "on" position, try cranking and it does eventually start. Revs fine, no lag, nothing wrong.
Put her in gear and start to pull off, and under load, she bucks like she is misfiring and has all the power of a 50cc moped. I go through the gears to get to the next exit so I can get off the interstate and, under WOT, achieve only 58mph max. She is firing on both cylinders as I can hear both pipes barking like they do when I am running it hard. In fact, just short of WOT is the only way to keep any momentum. However, when I get off the interstate, she runs fine. Does not die, revs just fine to 5 or 6K rpms, which is where I quit revving, so presume it would have gone higher had i twisted the throttle that far.
Plugs look fine, and were replaced about 6 months ago. I originally thought maybe it was the R/R crapping out as I have read about some of the stuff happening to others on the forum, so perhaps it was the spark plugs were not getting enough voltage to fire correctly causing a constant misfire. However, with it revving fine under no load and idling normally, it did not really stack up. Ditto for trash in the carbs, which should have nothing wrong at all since the tank and fuel lines were flushed out, and the carbs have been cleaned. Headlight works, all the are gauge lights are bright...nothing out of the ordinary with the electrics I can find, and I have a Yuasa AGM that is about a year old. Gas was from a 5 gallon container I had previously filled up with and ridden out with no problems within the previous week.

Can somebody offer some insight? My Vulcan has turned me into a "Do-it-yourself-er" and I have moderate troubleshooting skills, but I confess some of the maladies confound me. :confused: Thanks.
 

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Old Twistie Sticks Rider
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5,072 Posts
Are you sure there is no way it could be water in the gas, or the POG syndrone...???
Have you checked that it is not a California bike, I bought my 06 new in Tenn. and it was, and gave me fits till I fixed it... Did the gas tank have 2 rear vent lines (Cal. Mod. = 2)...??? Or did the 2000 Cal. Mods. have them then...
Just suggesting throwin some things out at you...
Have a good one...Old Dog...
 

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If only it had 6th gear..
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1,100 Posts
If your ignition was at fault, you should see evidence in the spark plugs and you said they look normal. I still think you've got some trash in your gas lines probably screwing with your main jets. You would be able to rev it more in neutral because you're not using a lot of gas doing that. Under a load takes quite a bit more though so that's when you'd experience the problem. Might want to take your petcock out at some point and peek at the screen. I know mine was disintegrated and allowed crap into my carbs. Good luck.
 

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Jackie Chan Stunt Double
Joined
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21 Posts
Discussion Starter #5 (Edited)
i had the petcock out a few months ago when I flushed the tank and had the carbs cleaned, and the screens looked fine. I got to thinking about it and I just got back last Monday from a trip out of state. Went about 600 miles and each time I stopped for gas, she did not want to start back up. It took several attempts to start again, and at one point acted like it might be flooded. I rolled the throttle and cranked and a big flash of fire shot out of the pipes (scared the crap out of me and the guy I was riding with). After a couple more cranks she started up. Each time afterward, nary a problem with power or running, but I figured when I got back I would look into it since it has not happened before.
Don't know if it is connected, probably is, so putting it out there.
 

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Premium Member
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306 Posts
Yea... those big " LOUD BOOMS " gets everyones attention.

(Me knows from experience too, KABOOM, OMG, did i just wet my pants?
That happens when ya get past the age of 60)
 

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Member? ... check.
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515 Posts
I'm thinkin' POOGS 5-0.
I keep my fuel tank ventilation clean, and I still have exactly what you are describing (minus the starting issue) once in a blue moon.

Read up on POOGS and the carb vent system. Also, I suggest iridium plugs and the ignition coil pick-up mod to cure the hard starting issue.

Good luck ...
 

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Registered
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33 Posts
Sounds like a fuel issue to me. Could you have gotten a bad fuel load when you filled up? If not, you may want to check the vacuum supply to the petcock for leaks. You may also want to check the condition of the diaphragm and filter in the petcock. If you have compression and spark, the only thing your missing is fuel.
 

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Git-R-Done!
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282 Posts
I agree with the "fuel issue" comments. Have you tried a Seafoam treatment yet? I would start there, as it is one of the easiest and cheapest possible remedies.

Good luck : )

AZ Kev
 

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..have a vulcan good day!
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4,508 Posts
Sounds like a fuel issue to me. Could you have gotten a bad fuel load when you filled up? If not, you may want to check the vacuum supply to the petcock for leaks. You may also want to check the condition of the diaphragm and filter in the petcock. If you have compression and spark, the only thing your missing is fuel.
X2 for dodger
 

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Premium Member
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1,766 Posts
I bet you are running on one cylinder. Carefully check that both exhaust pipes are hot prior to the goat belly. Either one of your carbs is not getting gas, or one of your coils died and that cylinder is not firing.

Jon
 
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