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Discussion Starter #1
Hi there,

Last weekend I bought a good condition 93 Vulcan. It ran great for a
week, no starting problems, got decent gas mileage, no backfiring.
Yesterday I hop on it to head to work in the morning. It had a bit of
a hard time starting, but did start. When I took off it felt like it
still needed to warm up. Going down the road through the gears it
would surge and lurche and backfire. I was able to limp it home and
rush to work in my car. After work I started it right up with no
problems at all. I let it warm up for a few minutes, took it on the road
and it did the same thing. I checked the spark plugs they weren't wet
and not too dirty (ie fouled and such). Checked the air filters, they
were fine.

The bike idles smoothe, it just when you give it some gas.

The day before I did put fresh gas in, but had run that tank about 1
gallon of it with no problems. Other than that I have not fiddled
with it.

Before I start ripping the bike apart, does anyone have any
suggestions to look for? Even though the plugs look fair I am going
to change them today. I will also be changing the battery after reading some of the other problems that have gone on with other members



Mark
 

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A "regular" battery will certainly do this. I'm curious why the previous owner sold it, and what he/she did to it. Check the water in the battery, and how well it's keeping a charge. Check the voltage at the battery when the bike is running at 3K rpms. It should be more than 13V. Check all this B4 you try to run it again. Don't wanna burn valves or damage electronics!

Also, if you haven't already done so, put Seafoam in the tank and run it at the problem rpms. It could just be common carburator crud.

One more thing - read the Vulcan Verses on this forum. If this is your first Vulcan, it will enlighten you to the common problems and fixes.
 

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Discussion Starter #3
update

After reading a few other motorcycle forums also. Alot of people do suspect the battery. To be safe I went ahead and got another battery. Also I bought some new plugs and installed them, the ones that were hard to get did look fouled. I also cleaned and re lubed the air filters. While checking vacuum lines I did notice that one line coming from the carb that looks like it is supposed to hook up to some kind of diaphragm just behind the tank has a screw in it. Obviously the previous owner or service station did this... Hmmmm, makes me wonder why now... I would have put seafoam in it, but my local dealers don't sell it, anyone know of any good alternatives that may be available at a auto parts store? Tomorrow morning after the battery is fully charged (new one on a trickle charger now) I will take it for a test ride before work (who wants to wait..lol), I will update afterwards..
 

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Please tell me you got one of the maintenance free batteries, right?

As to checking the battery and charging system, one of the guys here (Loran in Npvl IL?) pointed to http://www.electrosport.com/Images/fault_finding.pdf

If it had a "plain" battery in it, that might be why the original owner got rid of it. I almost did. I bought a brand new battery from WalMart, charged it up, and it was still hard to start cold and impossible to start warm. Bypassed the starter solenoid with a screwdriver, seemed to be a little better, but not fixed. I took apart the starter and cleaned it, made it a little better still, but didn't fix it. Wasn't until I couldn't get started after refueling that I looked the problem up on the net. And Tada! New maintenance free Yuasa YXT14AHL-BS made all my troubles disappear.

Anybody out there know something else like Seafoam?

Anybody out there know where the vacuum lines go?
 

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and the Adventure Cycle
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A guy at Auto Zone suggested Lucas Fuel Treatment because they were out of Seafoam.
I've got some left in a bottle I used for my truck, but haven't tried it yet.
Maybe this weekend.

As far as the hose .... ?? .... sorry
 

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The only other good cleaner other bikers have talked about is Shell Techron. You have to be careful what you put in the tank because you don't want your petcock screen to melt away.
 

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Discussion Starter #7
Update #2

I bought my battery yesterday, it was a wet one because the parts store didn't carry the sealed ones. I trickle charged it for 24 hours, the charge indicator said it was still charging. I put the battery in, and it started fine, but it still had the same problem. I also put some seafoam in it. Since the battery wasn't fully charged I put it back on the trickle charger and wait till it is. Could the low battery charge cause this still, even with a new battery in it? I keep reading about the sealed battery thing here and will eventually get one. I am not having starting problems though. As a test going down the road I did put it in choke and it did run a bit better, not great, but better. With normal choke off it feels like it is starving for fuel when I try to accelerate. Hopefully tomorrow will tell me its a better day and gremlins will fix this thing.....:confused:
 

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Don't trust a brand new fully charged battery unless it's maintenance free. I went through 2 brand new wet batteries, and neither fixed the problem.

If you don't have a manual, get one, and figure out where that vacuum hose goes. Seeing how you're not afraid of spending money, go ahead and pull the carbs and clean them. Or take it to a bike shop.
 

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Geez, if your bike sounds like Storm's, then you need to yank those carbs as well. Does it idle like his?
 

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Nothing but another opinion, but my bets are on a leak somewhere in a vacuum line. A vacuum leak can cause the bike to run bad at rpms higher than idle, and throwing more gas and less air (choke) would tend to richen the mixture and make it run better.

I'm wondering if the capped vacuum line you found may be from bypassing the anti smog stuff on the bike. Maybe something came loose from that bypass...
 

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Discussion Starter #11
yup another update

fergy said:
Nothing but another opinion, but my bets are on a leak somewhere in a vacuum line. A vacuum leak can cause the bike to run bad at rpms higher than idle, and throwing more gas and less air (choke) would tend to richen the mixture and make it run better.

I'm wondering if the capped vacuum line you found may be from bypassing the anti smog stuff on the bike. Maybe something came loose from that bypass...

Well I went out and got that sealed MF battery from Sears. The bike started right up, and I even had to adjust the idle. It did run a little better, but the same problem persisted. I rode it around the block for a good 15 minutes, the problem would clear briefly, then go back to bad. Arriving at home I looked at that vaccum hose coming out the right carb with the screw in it. I took the screw and plugged it into the diaphragm thing in front of the battery (whats that called?). I ran the bike again and it ran sweeter for about 3 minutes, then went back to that surging problem like it was starving for fuel... Something tells me that the diaphragm thing is part of the problem.

My question though is why in the world would it run great for a week then the next day just run like crud.... Very wierd...

I have checked all the other vacuum lines and they are good...


HELP PLEASE, I want to ride this weekend...

BTW anyone want to buy a brand new wet battery I wrongfully purchased before...LOL...:BLAM:
 

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Take it back and tell 'em it won't work on your motorcycle. Maybe you'll get your money back. I've got two like that. One does have something wrong (won't ever finish charging with the battery tender), and the other I keep charged just in case. Who knows when your gonna need 12 volts. Garage door opener remotes are 12 volts. He he. Sure starts better, right?

As to the surging, it still could be a vacuum line. I keep hearing that our gas tanks have a vacuum feed that doesn't allow gas to flow from the tank unless there's a vacuum. I haven't messed with this, but it's in the manual. What you might do is cut some of the vacuum hose off, take it to an auto parts store, and get a bunch of replacement hose. Then replace all the vacuum hoses with new ones.

If it were me, I think I'd just pull the carbs and clean 'em out real good. And check the petcock, filter, and the fuel line.
 

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Oh, that diaphragm thingy that your vacuum line plugged into - it can get screwed up if gas gets in it. You might wanna take it out and inspect it. If you have a shop manual, it shows the evaporative emission control system on page 2-28. I think there's a link on this forum somewhere for an online version of the shop manual.

When you say you took it around the block a few times, then I assume you leaned the bike into turns? Could be the fuel filter in the tank. Drain the gas and check out the filter on the petcock.

Those are a couple more things you can do before you have to pull the carbs.
 

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Discussion Starter #14
yet another update, need some help for this one

cegodsey said:
Oh, that diaphragm thingy that your vacuum line plugged into - it can get screwed up if gas gets in it. You might wanna take it out and inspect it. If you have a shop manual, it shows the evaporative emission control system on page 2-28. I think there's a link on this forum somewhere for an online version of the shop manual.

When you say you took it around the block a few times, then I assume you leaned the bike into turns? Could be the fuel filter in the tank. Drain the gas and check out the filter on the petcock.

Those are a couple more things you can do before you have to pull the carbs.
Thank you for the suggestion on the vacuum lines. This morning I went out and did some more poking around. I found a few oddities.

1. On the right hand side of the engine, there was a vacuum line poking out, close to right side air filter, followed it back and it went to the center of the carbs. I think this once went to the air filter, but don't see where it would attach?

2. From the petcock. The top rear hose had a piece of tape wrapped around some foam on it (previous owner may have been patching a leak?)

I am going to cut the tips off and go to the parts store here shortly and just replace the vacuum lines as suggested.

While I have the tank off I will drain it and check the petcock screen/filter.

A few questions now.

1)does anyone know where an online version of the vacuum line routing is ? I checked kawasakis site and couldn't find.

2) I keep reading about ear shave? Should I be doing it with my bike since I have it apart now?

3) What is an easy way to run some seafoam through the carbs without taking them out? (I am by far any type of mechanic)

Thank you for all your help....

Mark
 

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Discussion Starter #15
also

on the bottom of the tank, the fuel gauge cover has a nipple sticking out that nothing was attached to, was a vac line supposed to go to this?
 

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photohap said:
Thank you for the suggestion on the vacuum lines. This morning I went out and did some more poking around. I found a few oddities.

1. On the right hand side of the engine, there was a vacuum line poking out, close to right side air filter, followed it back and it went to the center of the carbs. I think this once went to the air filter, but don't see where it would attach?

2. From the petcock. The top rear hose had a piece of tape wrapped around some foam on it (previous owner may have been patching a leak?)

I am going to cut the tips off and go to the parts store here shortly and just replace the vacuum lines as suggested.

While I have the tank off I will drain it and check the petcock screen/filter.

A few questions now.

1)does anyone know where an online version of the vacuum line routing is ? I checked kawasakis site and couldn't find.

2) I keep reading about ear shave? Should I be doing it with my bike since I have it apart now?

3) What is an easy way to run some seafoam through the carbs without taking them out? (I am by far any type of mechanic)

Thank you for all your help....

Mark
# 1: That vacuum line should stick into the right side air filter into one of the slotted round tubes towards the rear. Be sure the hose does not bottom as this will clog the opening. Should go into "T" between the carbs at the other end.
 

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photohap said:
After reading a few other motorcycle forums also. Alot of people do suspect the battery. To be safe I went ahead and got another battery. Also I bought some new plugs and installed them, the ones that were hard to get did look fouled. I also cleaned and re lubed the air filters. While checking vacuum lines I did notice that one line coming from the carb that looks like it is supposed to hook up to some kind of diaphragm just behind the tank has a screw in it. Obviously the previous owner or service station did this... Hmmmm, makes me wonder why now... I would have put seafoam in it, but my local dealers don't sell it, anyone know of any good alternatives that may be available at a auto parts store? Tomorrow morning after the battery is fully charged (new one on a trickle charger now) I will take it for a test ride before work (who wants to wait..lol), I will update afterwards..
That vacuum line is part of the "coaster" epa stuff. Since the line was plugged, you may have your reed valves plugged in some form, marbles, coasters, etc. You may want to check that IF previous owner made an attempt to "coaster" the engine, that it is done completely and correctly.

Search forum on "coaster" or "reed valve' and you'll understand.
 

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Discussion Starter #18
Ok. I replaced all the vaccuum and fuel lines. I also emptied the tank and cleaned the filter in the tank.

Bike started in choke, had to adjust idle screw again. Once I got it started and running ok, I would notice every time it was on its side stand it wouldn't stay running, but would on its center stand......

Any clue to this?
 

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photohap said:
Ok. I replaced all the vaccuum and fuel lines. I also emptied the tank and cleaned the filter in the tank.

Bike started in choke, had to adjust idle screw again. Once I got it started and running ok, I would notice every time it was on its side stand it wouldn't stay running, but would on its center stand......

Any clue to this?
Sounds like carb float level problem. Or, partially clogged orifice somewhere in one of the carbs. Not sure if related, but there is a side stand switch, perhaps someone can shed some light on its relation, or not to your problem.
 

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Was it running better after replacing the lines? Just curious.

If you were sitting on it, and then leaned it in such a way that would mimic being on the side stand, how long before it would start to sputter?

I think your gonna hafta pull the carbs. I haven't had mine off or looked at them, but maybe a possible problem with the floats or needle valve. You've cleaned the screen on the petcock, so the only other area that deals with fuel levels would be the carb's bowls. You might just take those off if you can, and inspect them. Um, you can inspect the bowl level by attaching a clear tube to the drain plug and holding it next to the carb, while allowing fuel back into the carb. (OR - with the petcock turned off, measure how much fuel drains from the bowl to see if one of 'em is not filling all the way) It could be that one bowl is not filling with fuel. Not sure how the fuel pickup from the bowl to the carb is situated without looking at one. Could be like a spray bottle - when low on fluid, the spray bottle's pickup hose only works when the bottle is tilted in a certain way. In any case, pull the bowls before pulling the carbs, that may give an indication of the problem.
 
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