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Discussion Starter #1
For the past 2 weeks, my bike has been HARD to start. When you hit the button, it goes rar, rar, raar, raar, and then it will finally start. Sometimes on a couple tries, sometimes it takes 5 minutes of trying. My neutral switch was smashed and leaking oil for the whole summer, so I finally got the parts and swapped it out tonight, thinking maybe that was the culprit. I changed the oil too while I did that.

Didn't fix my starting problem.

I finally got it started and decided to let it run in neutral in the garage for about 15-20 minutes.

Well I go outside and it's BURNING hot, almost to the max temp, and "smoking" everywhere. I think it was steam maybe. Didn't stink too terrible. There was fluid coming out the little tube that comes out the bottom of the bike. WHen I turned it off I could hear the fluids inside bubbling. Yikes.

Not sure if the radiator fan didn't come on or something? or what. I'm at a loss.

I'm trying to get the darn thing in normal working order so I can sell it but keep getting blocked.

Any ideas?
 

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Discussion Starter #2
Forgot to mention. after the oil change, it would go "rar, rar, raar, rarr BANG (backfire)"
 

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Definitely sounds like your fans aren't coming on. There should be a wire on the bottom left of the bike plugged right in next to the radiator. Take that off and wedge something metal in there and it should turn your fans on for a second. Someone on the site showed me that.
 

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after the oil change, it would go "rar, rar, raar, rarr BANG (backfire)"
Sounds overfilled to me.....if not....stuck float will leak down gas into your crankcase (and cause overfill)....recheck your level....NEVER overfill...the "H" is a high mark, not necessarily what to fill to....I keep mine a hair below....(1/6-1/4 below)...
 

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First I'll say to anyone else, letting your bike run 15-20 minutes unsupervised is not a good idea. Not really a good idea to run it that long at idle even if you're there...
I only hope you haven't burnt up something...

So ...you have two issues...a fan that might not be working, and a starting problem....which could be anything from a loose wire to a bad battery (yes, even AGM batteries can go bad) Your starter might need a rebuild/cleaning.

You said you had a problem starting before you changed the oil, so I'll assume they are not related....but as Wolf mentioned....make sure you have the proper amount of oil in the bike.

Have you flushed the radiator since you had the bike? Go ahead and check your fan ....make sure your coolant is good and not overfilled too.

Some SeaFoam might be a good start, along with checking your ground, your battery and your starter.
 

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Discussion Starter #6
All good suggestions. I have to stop and get some coolant today and then I'll start going through each thing mentioned and see if I can find the problem.

Nitro - not sure what you mean there by wedging a piece of metal in there, but if there is an easy way to get the fan to come on, I'll definitely need to try that too.
 

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The backfiring is just because you were trying to start it so much. On my old bikes I used to rev the engine just before turning it off thinking that it would leave a little fuel in the chamber so it would start better next time. We not sure if that does anything or not but on these bikes it makes them pop loudly. I think it is indeed because of fuel vapors that get ignited on the exhaust stroke or something. I rebuilt my starter from the ebay kit and have had no more starting issues. The only thing to keep in mind is that the plate the brushes are on is slighly too large so had to grind it to fit. I have another starter I purchased just in case so if you need one I have one for $75 plus $10 for shipping.
 

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All good suggestions. I have to stop and get some coolant today and then I'll start going through each thing mentioned and see if I can find the problem.

Nitro - not sure what you mean there by wedging a piece of metal in there, but if there is an easy way to get the fan to come on, I'll definitely need to try that too.
I'm pretty sure what Nitro is saying is to disconnect the wire from the temp sensor at the bottom left of the radiator, and the run that wire to ground.
 

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Discussion Starter #11 (Edited)
Ok, got the coolant filled back. Pulled the wire off and grounded it - the fan came on. It had some corrosion on it, so I'm hoping that problem was just because of that corrosion.

Tried to start it just to see what it would do, and it almost started but didn't. After about 2 minutes of trying, I have a new symptom. It will slowly try and start "rar... rar.... rar..." and then it will give me a fast click "click-click-click-click". It's hard to tell but I think it's the solenoid? What normally makes that sound? Solenoid or starter?

edit - after looking around, sounds like the battery is probably too weak to start it (after all those attempts), that's causing the clicking. So I guess now I need to get a trickle charger, charge the battery back up, drain a little bit of oil, and then see what happens. If that doesn't work, try the pickup coil mod?
 

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repetitive clicks like that mean not enough voltage to keep the solenoid energized.

causes...

battery

grounds

bad connections (positive and neg)

battery voltage low (or dropping excessively CAN be caused by a bad starter, as it can draw too much current for the battery to handle)
 

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Discussion Starter #13
Well, I gotta go buy a trickle charger tomorrow, but I (hopefully) found the problem. Went to check some connections and noticed BOTH of my battery terminals were loose. Loose enough that I could turn them with my fingers. So, is it possible that was my original problem (hard starting), and that trying it over and over caused the battery to run out of juice?
 

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If the fan is coming on, and it is still overheating, it could be a number of things. There could be an air pocket trapped in the cooling system, a problem with the water pump, thermostat not opening, or a blockage anywhere, in the radiator or engine coolant passages. Radiator is a lot more likely.

Starting problem sounds like a bad battery. Or at least a dead battery. I would definitely rule that out before replacing the solenoid or the starter. I check for bad batteries by disconnecting the cables from the battery, and connecting a jump start pack to the cables. These things are made to jump start cars, and have more power than a motorcycle battery. Or you can use a car battery and jumper cables. If you still have the problem, then it is something else besides the battery. Almost all of the time when the starter turns the engine over slowly, then the solenoid clicks, it is due to a dead battery.

The Vulcan 750 is known for starting issues, especially when warm. Even with a perfect battery and starter, it seems to crank too slowly, at least to me. Combine that with a weak ignition system, and you wind up with a very weak spark at cranking speed. Mine has always backfired once in a while when starting it warm. But it does always start, and once it does, it runs fine.

Oh, one more thing. Your carbs are probably dirty as well. For some reason the idle jets tend to plug up on mine if it sets more than a week. I think it is caused by ethanol gas.
 

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Discussion Starter #16
I think I am good to go. Thanks for the tips and suggestions.

Drained a little oil (it wasn't really overfull, very little came out til the bubble showed up), cleaned the contacts on the radiator wire, charged my battery up, tightened all connections, and back in business. Runs good as new.

Now to get the for sale ad up...
 

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I run my oil level right at the top of the sight glass. Having never had one of these engines apart, I don't know how much room is in the sump. The only problem overfilling can cause is if the crankshaft hits the oil in the sump, and if that happens, you will know it. Also remember that the sump is mostly empty when the engine is running. I have been running 6 qts. in small block Chevys for decades, with stock pans, and they call for 5 qts. But while working on one once, I measured the distance from the crank to the oil level in the pan with 6 qts. and there was plenty of room with the engine off.

The Vulcan 750 holds 4 qts., so being a little low is not really a big deal. But many people with small dual sport bikes and scooters (I have both) that only hold 1 qt. have destroyed their engines by running them without enough oil. Just like tire pressures, I want all the oil in an engine that I can safely get in there.


Disclaimer: This is whatI do, and have never had any problems with doing so. But I am NOT recommending it to anyone else.
 

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I run my oil level right at the top of the sight glass. Having never had one of these engines apart, I don't know how much room is in the sump. The only problem overfilling can cause is if the crankshaft hits the oil in the sump, and if that happens, you will know it. Also remember that the sump is mostly empty when the engine is running. I have been running 6 qts. in small block Chevys for decades, with stock pans, and they call for 5 qts. But while working on one once, I measured the distance from the crank to the oil level in the pan with 6 qts. and there was plenty of room with the engine off.

The Vulcan 750 holds 4 qts., so being a little low is not really a big deal. But many people with small dual sport bikes and scooters (I have both) that only hold 1 qt. have destroyed their engines by running them without enough oil. Just like tire pressures, I want all the oil in an engine that I can safely get in there.
When I first got my VN, discovered I was running with Oil overfilled, but no problems.
I would guess maybe 1/2 qt. over ...?
(It was only on my FIRST Oil Change)
This was caused by my inexperience in the proper procedure (Center Stand) of checking accurately.

:smiley_th
 

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I run my oil level right at the top of the sight glass.
So, if your oil pressure gets a lil high, or your float sticks a lil and raises your level, yer screwed on the road.... "H", stands for "High" NOT full. And it does NOT take 4 quarts....optimum level in the sightglass is at 3/4....
Also, if you keep your level to thr "H", when you store the bike on the sidestand, the level is then overfull, and causing the lower pickup coil to sit in an oil bath, and causes hard starting, or even no spark. Especially on an older bike.

I really wish you'd stop posting all this misinformation....getting annoying.

Jerry...try standin on your head when talking....mebbe the words will come out of the proper orrifice.....small block Chevy, 6 qts ???.....OMFG !....one of the most pressure critical GM engines....jeezus !
 

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When I first got my VN, discovered I was running with Oil overfilled, but no problems.
Didnt you post that you needed another motor ? Sounds like problems to me....:rolleyes:

If you underfill, your engine will let you know to add....if you overfill, yer fooked....it'll blow stuff....
 
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