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Ever had problems with your VN750 running poorly or stalling? Take a look at the very helpful information that Trent has put together.  This page probably belongs in the troubleshooting section, but since it includes some very helpful hints and tips, it has been placed here.



From: "Trent" <tmills@ghg.net>
Date: Sat, 22 Jul 2000 21:56:57 -0500
Subject: 750 running poor at low RPMs



750 running poor at low RPMs

    I just thought I would archive this as it could have caused me lots of grief if I hadn't figured the problem
out. My bike is a 1999 VN750 with coasters, V&H classics and the ears removed. While I was commuting
in between my house and work she all of a sudden started running real bad at low RPMs (<3000). It was like
she was only firing 1/2 to 3/4 of the time. It happened so suddenly it was like someone flicked a switch. She
would run OK above 3000 RPMs, but was at the point she wouldn't idle at the original idle setting.  I got
her home and started trouble shooting. All four plugs were fouling like the floats were stuck wide open.
First thing I did was clean and tighten all battery and electrical connections. This did not fix the problem.
I then pulled the battery, topped the water off and charged her for a little while. I then put the battery back
in and that did not fix the problem. I almost did not suspect the battery because there was enough juice for
the lights to run brightly and to turn the motor over easily. Also, the battery was the one that came with the
bike new and I had only had her 1.5 years. I then took the battery to the auto parts place. they had no way
to accurately put a load on the battery and do a real test. They measured the surface charge at 12.5 volts. I
figured what tha' heck, I paid $30 and got a new battery. I was real careful to follow instructions for filling
the battery up with acid and charging her at 2A for about 8 hours. I put the battery in and she runs great again.
    Conclusion: the ignition system will not run properly with a battery that is even slight less than fully charged.
Even when the battery can turn the motor over and run the lights brightly this is may not be enough charge to
run the bike. Also, this problem can occur while on the road.

Later, Trent
VROC 2071



From: "Trent" <tmills@ghg.net>
Date: Sunday, November 05, 2000 11:20 AM
Subject: Re: VN750 - Poor Idle (again)



Straggler <straggler@erols.com> wrote:
>Well, it did it again.  A week after I replaced the plugs and battery
>and all of the other 750 checks, my 1996 750 is a 1996 VN 375 again.

Check the usual suspects before taking her in.

Vulcan 750 not running right? Some things to check:

 1. Battery connections.  Check all of 'em, including. the ground lead from the battery to the bike
 2. Water in battery ( is it at the right level?)
 3. How old is the battery? +2 years it could be suspect.  Have it load tested if possible.  Even a new battery can be bad
 4. Vent hose (1) from right hand air cleaner housing (3), it should not be "Bottomed out" (2)

 5. Flush out carbs. (loosen hex screw at bottom of carbs until they drain the gas)
 6. Bad gas (how long has it been running bad? Did you fill up at usual place or an unknown)
 7. Fouled plugs (Pull them and inspect)
 8. Check the plug wires (are they melted, checked them at night, do they arc? They shouldn't)
 9. Fuel petcock or gas vent. Open/close gas cap, does that help? If it does, you may need to replace or remove the valve in the gas cap.
10. Switch to reserve, does that help? If it does it could be the fuel petcock or cap vent.
11. If the bike is losing power, the tachomenter is fluctuating, or it suddenly dies while under power, then quickly jiggle the key in the ignition, or turn the key off/on before the bike comes to a stop.  If it comes back to life, the ignition switch could be failling.
12. Check the output of your Alternator (stator), AND the condition of your Regulator/Rectifier. If it is bad you may try one from ElectrexUSA .

 

See if any of that helps.

Later,
Trent
VROC 2071, 1999 VN750 "Marlin", earless and lovin it


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