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Just a regular guy
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Discussion Starter #1
I just bought a 2001 Vulcan 750 and rode it home. After a couple of days I went to ride it and it started at a very high rpm. I adjusted the idler and it ran at idle for about 10-15 minutes then shut off. Now it won't maintain enough rpms to stay on unless I stay on the throttle.
 

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Maybe cable throttle problems. Try turing the front wheel back and forth see if anything changes while the engine is running something may have been forceing the throttle cable to open up the carbs more. If you backed off of the idle rod adjustor, that may be why she will not idle now and having to keep the throttle advanced.
 

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Welcome to the forum!

It's possible that something in the carb was sticky (float/needle valve maybe) that was giving the engine some extra fuel. That would jump your RPMs, sort of like running it with choke. After it had run a while, it's possible that the problem cleared itself, meaning that you now need to turn your idle adjuster back up until you keep it steady around 1100 RPM.

These machines like to be run. I've found that if mine sits a while, it sometimes has hick-ups like what you described. Usually, just running it (and regular Seafoam in the tank) will take care of the problem.

It is also possible that, in the process of running it, one of the pilot (idle) jets got some crud in it. This would require some throttle to keep it running.

In either case, it wouldn't hurt to pull the drain screws and hose a bunch of spray carb cleaner up into the bowls and let it drain back out. Put the screws back in and give it a try.

I've (knock on wood) only had to pull the carbs on my Vulcan once, so we'll have to let one of the carb gurus on here give more specifics (and tell me where I went wrong).

Best of luck,
Hippie
 

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Just a regular guy
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Discussion Starter #4
Welcome to the forum!

It's possible that something in the carb was sticky (float/needle valve maybe) that was giving the engine some extra fuel. That would jump your RPMs, sort of like running it with choke. After it had run a while, it's possible that the problem cleared itself, meaning that you now need to turn your idle adjuster back up until you keep it steady around 1100 RPM.

These machines like to be run. I've found that if mine sits a while, it sometimes has hick-ups like what you described. Usually, just running it (and regular Seafoam in the tank) will take care of the problem.

It is also possible that, in the process of running it, one of the pilot (idle) jets got some crud in it. This would require some throttle to keep it running.

In either case, it wouldn't hurt to pull the drain screws and hose a bunch of spray carb cleaner up into the bowls and let it drain back out. Put the screws back in and give it a try.

I've (knock on wood) only had to pull the carbs on my Vulcan once, so we'll have to let one of the carb gurus on here give more specifics (and tell me where I went wrong).

Best of luck,
Hippie
Thanks, I have tried turning the idler back to no avail. And I read about the pilot jets, but am unsure how to go about them. I am unfamiliar with carbureted engines. Is this something I will be able to see with out much dis assembly?
 

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First post in this thread points to a download of the Kaw manual for our bikes:
http://www.vn750.com/forum/showthread.php?t=17667

It'll help you get familiar with some of the internal parts of the carb. For the no-removal carb cleaner flush I mentioned, pg 30 of the .pdf (2-13 according to the manual) has a diagram showing the location of the drain plug. There will be the same thing mirrored on the other side. Remember to put something under the carb to catch any gas/solvent that runs out (volatile liquids + potentially hot surfaces = bad).

If that doesn't solve the problem and carb removal is needed, directions are included in the manual (though some members may have a better method). Do a search on the forum about carb cleaning for lots of good tips/specifics.

Good luck,
Hippie
 

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Git-R-Done!
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I would have to suggest some Seafoam, or in my case, I like Lucas Oil's "tuneup in a bottle" - basically, some good injector/jet cleaner. I would suggest putting some in the tank, start it up, let it run for just a few to get it circulated through, then let it sit overnight maybe.

There are also some instructions in here somewhere about adding something directly to the carbs and letting them sit overnight. You might try that if the above-mentioned doesn't work.

I agree that these things like to be run, and mine also gets "tempermental" - sputters, coughs, etc - if I let it sit for more than 3 or 4 days without running. They are also notably sensitive as far as fuel and carbs go, and I find that mine does best if I run cleaner in it about every 3 or 4 tankfulls.

If that doesn't work, nor do the other suggestions, you might be looking at something a little more involved - other issues with carbs or maybe petcock. There's lots of info in here though, so if you keep at it, with the help of the "gurus" here, you should be able to get it figured out. Whether or not you can fix it yourself or have to take it into a shop - well, that's all based on your mechanical ability, time, etc. I had to have the carbs pulled on mine, and I took it to a good shop here in town - just didn't have the time or space (live in a condo with no garage - what the hell was I thinking?!?) Lol

Good luck = )

AZ Kev
 

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Git-R-Done!
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↑ ↑ ↑ Lol!
 

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Get it running, even if you have to stay on the throttle. Maintain the lowest possible constant engine speed for about ten seconds, then shut it off while maintaining throttle. Pull a plug from each cylinder and look at the electrodes (center hooks). If they are white, you are starving for fuel, if they are black, you are running rich.

That's a good place to start. Let us know what applying the choke does too.

I wouldn't try taking jets out on the bike since you have never seen the insides of the carbs.

There's really only one hard part to pulling the carbs: everything. But, after the third or fourth time you will be able to do it in around a half hour. It's rough the first few times, but the satisfaction of making it run is worth the effort.

When I hook the carbs back up for a trial run, I don't bother reattaching the cables right away. The choke and throttle can be manipulated by hand just to see if you can get it running again.

If you end up having to pull them, I can give you some of the tricks I've learned.
 

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Just a regular guy
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Discussion Starter #10
Thanks a lot guys. I got it running. What I did was I just kept starting it and playing with the idle knob. I think I found the spot seeing as it starts and runs reliably.

Now my issue is that is runs stays at about 3000 rpms when I squeeze the clutch lever to down shift and stays at a high idle. I have tried adjusting it down but can't seem to find a spot that doesn't drop it below 1,000. Is this normal for my bike?

And thanks Hippie I will download or purchase a manual when I get access to a computer. I do most of my internet through my smart phone.
 

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If only it had 6th gear..
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Now my issue is that is runs stays at about 3000 rpms when I squeeze the clutch lever to down shift and stays at a high idle. I have tried adjusting it down but can't seem to find a spot that doesn't drop it below 1,000. Is this normal for my bike?
I'm not following you. Are you saying that you can't get your bike to idle below 3000?
Or that I'd idles fine but in between shifting it revs at around 3000? Either way, no it's not normal. Tell a little more what you meant there and I'm sure we can help get to the bottom of it.
 

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Are you holding the throttle when you downshift? Also, do you have just a little bit of slack in both cables (accelerator/decelerator cables)? There should be a little slack, and turning the handlebars should not affect idle.

Still would be good to know if the choke does anything, or how the plugs read. Now that I think of it, follow the choke cable down to the carbs. Open up the choke and watch the plungers, when you close the choke they should return. Make sure that they do... the choke revs the engine up around to that range, at least when it' cold. Once hot, it might start dogging.

And on a hot engine, RPM should be 1100 +/- 50
 

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Just a regular guy
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Discussion Starter #13
Ok, here is my situation/problem(s);

I bought the bike from a friend. He was riding it last year and the past few years so
I know I didn't buy a broken bike. He let it sit up over the winter without and preparations. When I first started thinking about buying it, I went over and we changed the spark plugs and got it running.

Once I bought it, I rode it home and let it sit a couple of days while I got it registered. When I went to start it, it cranked up at 4000 rpms, I adjusted the idle and got it to 1700(thinking this was normal, like on a car) and left it running while I went inside.
When I came out, it was off. After that was when I couldn't get it to maintain rpms. After playing with it, I got the idler to a spot where I could ride it.

Then it started revving up real high when I would attempt to downshift. I adjusted when I was shifting and the problem went away for the most part but now it is back. It also revs at seemingly odd moments such as when I am sitting at a red light or even while I am riding down the street the rpms will creep up. It has also started dropping in the last day or 2 acting like it wanted to turn off. I just put in Gumout to try and clean the system.

I am hoping that works. If anyone has any ideas or critiques I will listen. Just remember I am a novice.

Thanks,
Chris
 

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Old Twistie Sticks Rider
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The Gumout seems to me like the right path for now, but most of us like SeaFoam... I would give it a chance to clean up before I got into anything much... Kinda seems like gunk in the carbs to me... Others know more and will respond...
Have a good one...Old Dog...
 

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Just a regular guy
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Discussion Starter #15
I hope so. I wanted to use Seafoam, but couldn't find it anywhere I looked.
Should I let it sit a few days? Or should I ride it like crazy to work it in?
 

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Hmmm

After 2 carb removals I noticed this with mine too. I personally believe it has to do with that knurled idle adjuster. Mine's just dang finicky. I can turn it half turn clockwise, rpm stays same, I turn it 1/4 turn anticlockwise, and she idles down to 900-1000.
I also did the Gumout thing and seemed to help somewhat. She'll rev up some when you first give it a lil spray, but will then die down again. I also have a slightly loose throttle assy, so with cables closer to rider, it idles normally, when cables are away, it idles higher.
No solutions, just personal observations. But Im gonna mount my twistgrip tighter, then lube all 3 cables (requires removal though). Seems like on mine, a cable is sticking some (it IS an 85 from a barn). Even taking off sidestand changes the idle, so I adjust all with bike perfectly vertical.
Remember too, to make adjustments at operating temp.
 

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Crap, I WAS in 5th gear.
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If you are getting popping in your exhaust as well, the problem returning to idle might implicate the "Air Cutoff Valves." These are also known as coasting enricheners. I think you can change them with the carbs on the bike-- it is not difficult. I just had to change mine in my 2001.
 

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Chris I don't know if this is your problem but here's what I had and maybe it will help you. All of a sudden my bike had idle issues especially when it was hot and after running for awhile. The RPM would climb to over 2000 and I couldn't figure it out. Turned out to be a warp in the rubber manifold on one of my carburetors that seemed to allow air to leak in to the cylinder and had the same effect as opening the throttle. You may want to check on that. Actually there's a way of blowing smoke and see if it gets sucked in behind the carbs when the engine is running.

Good luck, that can be a pain in the butt.
 

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why...whyyy...WHYYY

Why did engineers ever start making so much stuff "automatic" ?...bad as WinXP and Win7, lol...

These are also known as coasting enricheners
...thanks for mentioning that...I didnt even know there was such an animal... no wonder my VN doesnt f*rt on decel like all my Harleys did, lol...
 

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Just a regular guy
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Discussion Starter #20
Ok. I put in the Gumout on Thursday last week, and rode it about a mile home but the weather was terrible here(we had an f1 Tornado touch down) so I haven't been able to ride it until today.

It didn't seem to help. The power was real spotty. It idles high... then low. It idled so high at one point I was able to cruise at 30mph in 2nd gear without touching the throttle. When I stop at a stop sign or any another stopping point, it idles up to about 4000rpms. If I act like I'm going to release the clutch to start moving, the rpms starts to lower. The rpms also started lowering unexpectedly today. At one point it almost cut out as I was turning in front of a vehicle that I should have had no problem beating.

This is really starting to make me nervous about riding. By the time I got home from my experiment/ride it was dark and I also live in a condo with no garage or outside lights, So I will check my plugs tomorrow after work. It seems like and o2 problem, or a fuel issue.

@Bazooka_Luca the choke is operational, and there is enough slack. Also it happens when I'm not touching the throttle.

@kelley2001 When it is idling high there is a lot of popping, which is making me think an o2 issue.
 
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