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Discussion Starter #1
Hey all,

So in my heart of hearts I think (hope) this must be a simple problem.

The other day I started up the bike just to run 'er for a little bit and enjoy the sound only to have a few, brief seconds of running followed by endlessly cranking the battery starter to no avail.

I decided to give it some time and wait till tomorrow. My gut was telling me the engine wasn't getting gas, for some reason, so I did nothing. This morning I could get it started but had to hold the throttle open to maintain any kind of run. Also there was a lot of sputtering and unevenness from the exhaust.

Any kind of help is greatly appreciated. I'm still learning how to diagnose these problems; hope it isn't a biggie.
 

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Hi drizdan,

Make sure you have a good charge on that battery before trying again.
Kinda sounds like low battery power. The VN750 demands a good strong battery to run properly.

~~C8>
.
 

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Discussion Starter #3
No, it's not the battery.

Special update! Now the bike is back to not starting again. I feel like it's a question of fuel. Intake outtake back break I don't know.
 

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ok ...
Have you pulled the plugs to see if they are wet with fuel ?
Have you checked to see that the petcock delivers fuel to each carburator ?
Have you checked that the carburator float bowl fuel levels are good ?
Have you looked for vacuum lines cracked, broken, or disconnected ?

~~C8>
.
 

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Can you tell if there is good compression in the cylinders?
Does running the choke on full make a difference?
Crack open the carb fuel bowl drains, and see if you have fuel in the bowls.
Have you checked to see that you are getting a nice fat blue spark at each spark plug?

Check some stuff out ... and let us know some more info ...

~~C8>
.
 

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Discussion Starter #6
Update update: I pulled the spark plugs and took a look. The rear two are fine, the front two are black and wet. How do I check compression? The fuel hoses all seem to be fine. How can I check the float bowl levels? I'll go crack the drains and see if there's fuel.
 

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I check compression by pulling the spark plug, detaching it from the wire, and moving the wire way, way far away from me. Place your thumb against the now-open spark plug socket and turn the engine over - you should feel suction against your thumb. Someone else may have a more accurate - or safer! - way to do this.

When was your bike last ridden? Might just need a thorough carb cleaning.
 

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Old Truck Junkie
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Dry the spark plugs and let the cylinder air out. Give the plugs a good brushing and re-enstall. Try and start engine.
 

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Also, if you haven't been riding much then maybe you should try new gas in case you got some moisture in it and add some seafoam.
 

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If only it had 6th gear..
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Sounds like a stuck float in the front cylinder wet and black plugs = too much fuel. If you're going to use your finger to do a quick check on compression, do it from the side with the short spark plug cap. It's shallow and easier to get your finger on it. I think your front cylinder is flooding with gas tho. You should make changing your oil a high priority after you fix this since it may now have gas in it. Good luck. Hope you get er running.
 

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Linkmeister Supreme
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Everyone has given you some good advice for things to check.
Here is a link to an online repair course that may help you:
http://www.dansmc.com/MC_repaircourse.htm

I bought an inexpensive compression gauge a few years ago for about $20.
Check Harbor Freight for one. Get one that screws into the plug threads, not just a tapered rubber end that you press in place while cranking the engine.

Vn750 specs call for 129-199 psi. 100 psi will blow your thumb off the plug hole, but will not let the engine run correctly.
 

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Just a thought...

Just a thought, but youre not overchoking, are you ?...when I first got my Vulcan, I always did full choke and cranked until it popped...then went to off, and it wouldnt do anything....
Ive found that in 72 deg plus weather, a few cranks at halfchoke is enough, and if over 80 degrees, no choke needed...and dont be tweaking the throttle either while starting...I hit mine ONCE with half choke, then no more...seems like these carbs flood easily...
Just my personal experiences though...but mine was hard starting too before I reduced the choke...hot days (relative I guess) no choke at all...
 

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If only it had 6th gear..
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True.. I almost never give choke to mine unless in the low 60's, then around half like you said.
 

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Jack of all trades
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I never go above half choke. I find myself using less after the iridium plugs.
 
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