Wont stay running after start - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 05-16-2010, 09:28 PM Thread Starter
Junior Member
 
Join Date: Jul 2009
Location: Shoreham NY
Posts: 3
iTrader: (0)
 
Wont stay running after start

2003 VN750 with 14,000 miles


2 months ago the weather allowed me to take a spin and fill up the tank with fresh gas

About a month ago I went out to run the bike and after bringing it up to temp I shut it down. The next day I noticed gas dripping from the carbs. It looked to be the choke plungers. I pulled the carbs and replaced the plungers. I also wiped down the carbs and cleaned up any varnish or grime I could see, I didn’t disassemble or rebuild anything.

I finally got everything back together and changed out the coolant while I was at it. Now I have some issues.

The bike will start run for 60 to 90 seconds start to idle down and then just die. Its hard to restart but gets better If I let it sit a bit. When I do get it started some times it sounds like only one cylinder is firing for a few seconds. I checked the carbs and they have fuel in the bowls after it shuts off. It also seems like the higher the idle the longer it runs.


I have fresh gas with sea foam in it now and ran it for 5 or 6 times today trying to figure out what’s going on. Im going to try a carb cleaner flush out as soon as I can. I did notice the vacume at 2000 rpm was only 0- 5 inHg and bouncing rapidly between the two…is this normal should it be more steady?


Thanks for any and all help

Ron
rhamski is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old 05-17-2010, 07:40 PM Thread Starter
Junior Member
 
Join Date: Jul 2009
Location: Shoreham NY
Posts: 3
iTrader: (0)
 
update:

After sitting overnight I drained the carbs and removed the drain screw to shoot carb cleaner up into the float bowl. I did both sides.

I removed the air cleaner elements, they looked dirty so I cleaned the foam and put them to the side to dry.

I pulled the plugs, which had no more than 3000 miles on them, for inspection and noticed they were carbon coated, not enough to be a primary culprit but enough that I cleaned them all up.

based on the plug condition and for fun I checked the F/A screws and found them out about 6 turns, I reset them to 3 turns out from full in.

I started the bike up with the choke open enough to hold a 2000 rpm idle, it sounded good and strong. I sprayed some carb cleaner into the air box a few times letting the idle ramp up 500 rpm, letting the bike run a bit and them hitting it again. I did this about 8 times with just a short burst of cleaner each time.

The bike ran for about 5 minuets and then started to die, it ran long enough for the temp gauge to get just past the second hash mark into the normal range.

I broke for a quick dinner.

I returned and started the bike right up, it took a little choke to keep it going and it sounded like one of the cylinders was not firing. A little throttle got things right with that.

After about 3 minutes it started to die again. I used the throttle to rev up to 2500 - 3000 rpm. and the bike ran fine, as long as I held it over 2500 rpm. I ran it until the cooling fan came on and then let off the throttle and it revved down normally and as it fell below 2000 rpm it died.

Should I keep cleaning as I did or is this a definite problem that requires a carb pull and rebuild?
rhamski is offline  
post #3 of 5 (permalink) Old 05-17-2010, 08:01 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Pilot jets are clogged, remove carbs and clean.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
 
post #4 of 5 (permalink) Old 05-24-2010, 01:50 PM Thread Starter
Junior Member
 
Join Date: Jul 2009
Location: Shoreham NY
Posts: 3
iTrader: (0)
 
Just a quick update:
while I know i should have pulled and cleaned it was such a pain the first time I thought I would clean in place and see how it goes.

Day 1, clean fresh fuel with seafoam, ran for a while. Drained carbs and did a big flush out with carb cleaner.

Day 2, more flush out...running longer

a few days later and one more flush out, running good...went for a nice run around town.

Sat for a week with good gas and seafoam. Started right up and dident die out when the choke was off. i was detailing and cleaning so I dident go for a ride but I think Ill start comutting again(80 mile round trip) and see how it goes.
rhamski is offline  
post #5 of 5 (permalink) Old 05-24-2010, 02:48 PM
Members who have donated towards server costs
 
fergy's Avatar
 
Join Date: Mar 2006
Location: Kyle, Texas
Posts: 4,054
iTrader: (3)
   
I think you might have gotten lucky with the seafoam getting into the pilot jets and actually clearing them out. The pilots meter your fuel when the bike is idling and just above idle until your other jets kick in and the pilots don't have much to do with the mix. Since it ran pretty good until it dropped below 2000 rpms, (right about when your pilot jets take over) it was obvious that they were clogged. Seafoam is wonderful stuff. Glad for you!

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