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Discussion Starter #1
I have just bought a 1985 VN700. It didnt have any gas when I looked at it, so it turned over but it obviously didnt stay running. I brought it home and put gas in it and sure enough even with gas it will turn over and run for a split second, but with any gas given or even choked it will die. I assume it might be a carb problem. Please if you have any information on this issue or if you could just point me in the right direction that would be great. I want to learn my self I dont want to have to take it to a mechanic. Thanks for your help.
 

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Linkmeister Supreme
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Welcome to the Vulcan madness Matthew.

If the bike has been sitting for a long time and the fuel evaporated out of it in your Texas heat, the tank and carbs could be gummed up with varnish. Try pouring 6-8 ounces of Seafoam fuel conditioner or even some fuel injector cleaner into the tank of fresh fuel. Find the carb float bowl drain screws and drain the fuel out of them. Turn the petcock (fuel valve on the bottom left side of tank) to the Prime (PRI) position found only on the earliest 3 or 4 model years. This will allow fuel with the Seafoam to flow and fill the carbs too. Let it sit for a day or two, and try to start it once in a while.

If it still won`t run, check for fuel flow from the tank, and vacuum hose to middle nipple on petcock is not broken or cracked.

Here`s a link to the Vulcan Verses with info on flushing out the carbs through the drains.
http://www.vn750.com/forum/showthread.php?t=1080

You might find this link interesting too.
http://www.dansmc.com/MC_repaircourse.htm
 

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Welcome, Matthew. As OlHoss said, carb problems are common on bikes that sat. When you change the oil, do it with the bike on the sidestand. After removing the drain plug, stick a finger in the hole and pull out the spring, flat washer and screen. Look for any foreign material on the screen, especially chunks of rubber. Bikes of your's age tend to have deteriorated balance dampers. The rubber damper parts usually show up on the screen before major damage occurs (see my project bike info in signature). Also, check the tank for rust since you're in a pretty humid environment. It forms because of condensation in the bottom of the tank first. Try to get a look with a small flashlight and mechanic's mirror.
 

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Discussion Starter #4
Thank you Olhoss and flightcontrol!!! I will do both, drain gas from carb then put in fuel injector cleaner let sit for a day or so and see if runs. Also, I will change the oil and check spring, flat washer and screen. One question though, does the spring, flat washer and screen just pull right out with a, for lack of better word, tug?
 

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Discussion Starter #6
Also one more thing. There is a gooey substance that is now on my garage floor that feels like oil but smells like gas...It had to of happened when I was trying to start it going back and forth from the PRI to RES on my petcock. Any idea where that could be coming from and why?
 

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MANIC MECHANIC
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sounds like a stuck float as far as the rust muratic acid and naval jelly use the search to find it
 

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I used The Works toilet bowl cleaner, avaiable at WalMart for around $1.25 per 16 ounce bottle. It runs around 20% hydrochloric acid and the muriatic is 40% hydrochloric. Fergy, a member of this forum, has a good write up on using muriatic acid. Locally, I could only find muriatic in a gallon container, and you won't need that much. I think I only used one bottle of The Works to do two tanks. When finished, I poured what was in the tank through a coffee filter and put it back in the bottle.

You can do a search for my write up here, or Google: The Works Tank Cleaner. One guy used acetone to dry the tank. I don't recommend this as one spilled drop instantly ate my tank paint. After rinsing the tank with water, immediately give it a really good shot of WD 40. It will displace the water and prevent flash rusting.
 

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Linkmeister Supreme
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Also one more thing. There is a gooey substance that is now on my garage floor that feels like oil but smells like gas...It had to of happened when I was trying to start it going back and forth from the PRI to RES on my petcock. Any idea where that could be coming from and why?
sounds like a stuck float as far as the rust muratic acid and naval jelly use the search to find it
The gooey crap on the floor sounds like rotten old gas on the way to becoming varnish or gum.:(
 

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Matt...I had all of these issues when I got my bike.. it had sat for probably 5 or 6 years.. ran seafoam (great stuff btw.. cant live without it) thru many times.. jsut seemed to get worse... finaly had a float stick on me so I ended up pulling the carbs (not that hard really).. took the carbs apart to clean em (I'm pretty sure they had never been off of the bike since it was new in 1992!.. had enough stuff in the carbs to build a 2nd bike with!..while the carbs are out I am doing an ear shave.. might as well right!.. my point is.. you will probably just have to bite it and go all the way with this old girl.. it will be worth it!
 

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carbon unit
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any pointers on removing my carb? Also how do I sync my carbs once they are put back on the bike
?
try putting the words Synchronize the carbs after:

Search VN750.com

then click the "search"

I'm thinking it might work for the carb removal question as well.

You're going to like this bike.
 

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as long as you dont mess with the sync screw and only clean the insides of the carbs you should be good to go.... if your dead set on it.. you can make a "man-o-meter".. there is a few good write ups about it.
 

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Linkmeister Supreme
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I just did a search on "manometer" and came up with many hits. Here is one:
http://www.vn750.com/forum/showthread.php?t=10647&highlight=manometer

knifemaker suggested once that on a twin cylinder bike that syncronization is not nearly as difficult or necessary as on a 4 cylinder. You can often get by with just making sure the throttle linkage on each carb start to open at the same time. That`s a good place to start anyway.
 

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Discussion Starter #15
Ok any tips on taking the carbs off? I have the Clymer manual it tells me to take off the thermostat housing and drain the coolant. Do I have to do that to take the carbs off? Does anyone have detailed steps on the best way to remove the carbs for a 1985 VN700?
 

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carbon unit
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Hey, uhm the search function really does work good.
I used it... and found the following...



Digitalman
10-22-2006, 10:08 PM
My 1990 750 Vulcan was idiling rough and stalling so I decided to go for it and pull the carbs for the first time. It's not as bad as it looks. I used to work on cars and I've seen every chemical "overhaul in a can" and have never been impressed by any of them. If you want the carbs cleaned, you have to pull them and take them apart. There are many air intake ports that fuel from the fuel system never come into contact with that probably need cleaning (as mine did after 16 years). This is why I beleive that tank fuel additives won't help in all cases. First bit of advice is to be patient, it's not a 1/2 day job.

I got some good advice on this website (after starting unfortunately). In a nutshell, pull the fuel tank, remove the hoses to the carbs, leave the carb to cylinder boot on the front cylinder while leaving the rear boot on the carb (very helpful advice). Remove the carbs from the RIGHT side of the bike while prying up on the upper intake duct (it's very sturdy). You may have to remove the air intake boots the connect to the duct, which can be a little trickey. A good long prybar is helpful. Disconnect the choke and throttle cables and there you have it. Lay the carbs on a clean towel on your workbench and now carefully remove all screws and covers from the carb (one side at a time) and thoroughly spray with Gumout carb cleaner with straw attached. Carefully unscrew the two jets that have screw slots and hose down with gumout. Repeat the process and reassemble. There's no need to remove air cleaners, thermostat housing, throttle linkage, etc. Good luck and I hope this helps out. Bottom line is, don't be scared...


you could have answered your own question without the wait.
how cool is that?
 

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Discussion Starter #17
Just out of curiosity what did you search to find that? Because I tried a few different searches and didnt see this one. Thanks for the info. I am new to using forums for info.
 

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carbon unit
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I just put removing the carbs into the search window (toward the top right of this page/window) and it was the 7th listed posting down.

good luck with the carb removal. take your time. If it get's frustrating...take a break.
 
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