Very odd problem- Surge and Backfire - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 38 (permalink) Old 07-11-2006, 01:21 PM Thread Starter
Member
 
Join Date: Jul 2006
Location: federal way
Posts: 63
iTrader: (0)
 
Very odd problem- Surge and Backfire

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
photohap is offline  
Sponsored Links
Advertisement
 
post #2 of 38 (permalink) Old 07-11-2006, 04:46 PM
Once Banned
 
cegodsey's Avatar
 
Join Date: Jun 2006
Location: Bryant, Arkansas
Posts: 2,125
iTrader: (0)
 
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.

2000 A16
Drilled baffles
$65 leather saddle bags
Kuryaken grips
relocated R/R
de-badged
25,000+ original owner miles
cegodsey is offline  
post #3 of 38 (permalink) Old 07-11-2006, 09:44 PM Thread Starter
Member
 
Join Date: Jul 2006
Location: federal way
Posts: 63
iTrader: (0)
 
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..
photohap is offline  
 
post #4 of 38 (permalink) Old 07-11-2006, 10:24 PM
Once Banned
 
cegodsey's Avatar
 
Join Date: Jun 2006
Location: Bryant, Arkansas
Posts: 2,125
iTrader: (0)
 
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?
cegodsey is offline  
post #5 of 38 (permalink) Old 07-12-2006, 05:43 AM
and the Adventure Cycle
 
hyperbuzzin's Avatar
 
Join Date: Jun 2004
Location: Western PA
Posts: 6,138
iTrader: (1)
   
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


AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC


"When life throws you curves,
Aim for the apex."

Author Unknown
hyperbuzzin is offline  
post #6 of 38 (permalink) Old 07-12-2006, 08:20 AM
Members who have donated towards server costs
 
Loran in Npvl IL's Avatar
 
Join Date: Jun 2004
Location: Naperville, IL
Posts: 382
iTrader: (0)
 
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.

Deuce (Loran Naperville IL)
1995 VN750 (Black w/ 2004 tins - no teal)
2003 VN750
Both have: - F&S Bags & brackets
- Corbin seat w backrest
- Progressive suspension.
- Kury iso goldwing grips
2 1983 V65 Magnas
2 1985 V65 Mangas (1 which is in many parts)
Loran in Npvl IL is offline  
post #7 of 38 (permalink) Old 07-12-2006, 07:13 PM Thread Starter
Member
 
Join Date: Jul 2006
Location: federal way
Posts: 63
iTrader: (0)
 
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.....
photohap is offline  
post #8 of 38 (permalink) Old 07-12-2006, 07:46 PM
Once Banned
 
cegodsey's Avatar
 
Join Date: Jun 2006
Location: Bryant, Arkansas
Posts: 2,125
iTrader: (0)
 
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.

2000 A16
Drilled baffles
$65 leather saddle bags
Kuryaken grips
relocated R/R
de-badged
25,000+ original owner miles
cegodsey is offline  
post #9 of 38 (permalink) Old 07-13-2006, 01:10 PM
Once Banned
 
cegodsey's Avatar
 
Join Date: Jun 2006
Location: Bryant, Arkansas
Posts: 2,125
iTrader: (0)
 
Geez, if your bike sounds like Storm's, then you need to yank those carbs as well. Does it idle like his?

2000 A16
Drilled baffles
$65 leather saddle bags
Kuryaken grips
relocated R/R
de-badged
25,000+ original owner miles
cegodsey is offline  
post #10 of 38 (permalink) Old 07-13-2006, 01:32 PM
Members who have donated towards server costs
 
fergy's Avatar
 
Join Date: Mar 2006
Location: Kyle, Texas
Posts: 4,054
iTrader: (3)
   
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...

Fergy
Kyle, TX VN750.com member #707 VROC#19556
2002 VN1500 Classic
Spline Lube Procedure, with photos, R/R Relocation and Coil Mod
Rusty Tank Cleaning!
Electrical Fault Finding Flowchart
SEAFOAM JUNKIE!


fergy is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome