Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums - Reply to Topic
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

Thread: 1985 VN700 Carb/Petcock Issues. At my wit's end. Reply to Thread
Title:
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:
 

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










  Additional Options
Miscellaneous Options

  Topic Review (Newest First)
04-02-2018 02:02 PM
lugnut1009 I'm no expert, but when I tuned my carbs for the ear shave on my 750 it was running lean and doing this after a little riding. If I was patient, after a while it would crank back up and idle fine. When it's running, does it run well at WOT? You said it idles good. Just curious if it was ever rejetted, stock jets? Stock air filter? I have converted my factory petcock to not use the vacuum port because mine was filling my crank case up too. I simply turn the gas off (when I think about it) and haven't had an issue since.

** Not sure if I'm helping but adding my .02 cents anyway.
04-02-2018 08:49 AM
e_filippo
Quote:
Originally Posted by Spockster View Post
-

Take note next time it stalls, while you're still rolling,.... Are the dash lights on or off? If your oil light etc. don't come on when it dies, you'll know it's the switch that killed it. That problem is usually the "puck" inside the switch needing cleaned and the springs stretched. There's a sticky thread on that I think.
All of the lights stay on, and everything still operates as normal, but the motor won't fire. It'll spin and spin to its heart's content, but won't even sputter.
04-01-2018 07:18 PM
Spockster
Quote:
Originally Posted by e_filippo View Post
Next time I have it running, I'll bring a spare plug and test it out. I actually have an issue with the ignition where I have to jiggle the key occasionally for it to run the starter, but it's never been an issue with cutting ignition while riding. I'm still able to spin the starter when it dies. As far as when it dies, it'll usually sputter while I'm going straight, then die either while I'm turning, or I pull the clutch in to stop.
-

Take note next time it stalls, while you're still rolling,.... Are the dash lights on or off? If your oil light etc. don't come on when it dies, you'll know it's the switch that killed it. That problem is usually the "puck" inside the switch needing cleaned and the springs stretched. There's a sticky thread on that I think.
04-01-2018 11:29 AM
e_filippo
Quote:
Originally Posted by Spockster View Post
I recall reading that the spark plug cap has a resistor built in. Wolfie said he took his out of the caps.

Since you have spark, it's reading like a clogged pilot jet on the rear cylinder. But that doesn't explain it dying on down the road.

Need to know if the spark is dead immediately after it dies. If I didn't have a spark tester ($5 @ Harbor Freight), I'd carry an old plug to check it with. I guess the best plan would be to warm it up fully, and stay close to home.

When it dies, are you just riding straight down the road, or have you slowed down and making a u-turn? Just wondering if it could be a wiring problem in the headlight or neck plugs. Also, is there ever any problem with the switch not turning on? Like maybe needing to wiggle the key to get it lit up?

Seems like maybe two problems, a dirty rear carb and some electrical bug.
Next time I have it running, I'll bring a spare plug and test it out. I actually have an issue with the ignition where I have to jiggle the key occasionally for it to run the starter, but it's never been an issue with cutting ignition while riding. I'm still able to spin the starter when it dies. As far as when it dies, it'll usually sputter while I'm going straight, then die either while I'm turning, or I pull the clutch in to stop.
04-01-2018 10:41 AM
Spockster I recall reading that the spark plug cap has a resistor built in. Wolfie said he took his out of the caps.

Since you have spark, it's reading like a clogged pilot jet on the rear cylinder. But that doesn't explain it dying on down the road.

Need to know if the spark is dead immediately after it dies. If I didn't have a spark tester ($5 @ Harbor Freight), I'd carry an old plug to check it with. I guess the best plan would be to warm it up fully, and stay close to home.

When it dies, are you just riding straight down the road, or have you slowed down and making a u-turn? Just wondering if it could be a wiring problem in the headlight or neck plugs. Also, is there ever any problem with the switch not turning on? Like maybe needing to wiggle the key to get it lit up?

Seems like maybe two problems, a dirty rear carb and some electrical bug.
04-01-2018 08:29 AM
michiganteddybear basic rule of crooked thumbs for plug wire resistance is around 1k ohm per foot for resister wires (which I believe ours are)
04-01-2018 01:51 AM
e_filippo
Quote:
Originally Posted by Spockster View Post
Quote:
Originally Posted by e_filippo View Post
The rear cylinder's plugs are wet when I pull them, the fronts are not. When the bike runs, it sputters on the rear cylinder until you get it up to about 4k, then it kicks on. As far as the vent goes, I wasn't finding where it's supposed to be on this tank. I have a spare tank that has a little 1/4" or so outlet on the tank right between the mounting screws for the gas cap, but the one on the bike doesn't have that. The cap has a small tube that fits right in the little outlet, so is that supposed to be on the tank?
Think mine has the little rubber nipple sticking up out of the tank, under the cap. Then the cap closes down on top of the nipple, I need to look at mine though. But I'm thinking it's probably not POOGS, since you have wet plugs on the rear cyl.

There was some discussion over this winter about some tanks having different venting.

Do you think it's running on both cylinders when it runs? Wet rear plugs with dry fronts, and the engine dies. Makes me think the front isn't running at all, and it dies when the rear floods out.

Does the front cylinder get as hot as the rear? Were the jets cleaned when the carbs were worked on?

Need to know what the spark is actually doing, and if it loses spark anywhere when it dies.
The rear cylinder doesn't seem to run when the bike is running. Based on the noise from the exhaust and the pipes heating up, the front is doing most of the work. I've checked all of the plugs for spark, and they're all getting it. Sometimes the rear cylinder will kick on or "catch" at about 4k rpms.

Also, I tested the resistance of my plug wires today and got one wire that was waiting higher than all the others. Anyone have any idea what they're supposed to be?
03-31-2018 07:59 PM
Spockster
Quote:
Originally Posted by e_filippo View Post
The rear cylinder's plugs are wet when I pull them, the fronts are not. When the bike runs, it sputters on the rear cylinder until you get it up to about 4k, then it kicks on. As far as the vent goes, I wasn't finding where it's supposed to be on this tank. I have a spare tank that has a little 1/4" or so outlet on the tank right between the mounting screws for the gas cap, but the one on the bike doesn't have that. The cap has a small tube that fits right in the little outlet, so is that supposed to be on the tank?
Think mine has the little rubber nipple sticking up out of the tank, under the cap. Then the cap closes down on top of the nipple, I need to look at mine though. But I'm thinking it's probably not POOGS, since you have wet plugs on the rear cyl.

There was some discussion over this winter about some tanks having different venting.

Do you think it's running on both cylinders when it runs? Wet rear plugs with dry fronts, and the engine dies. Makes me think the front isn't running at all, and it dies when the rear floods out.

Does the front cylinder get as hot as the rear? Were the jets cleaned when the carbs were worked on?

Need to know what the spark is actually doing, and if it loses spark anywhere when it dies.
03-31-2018 07:13 PM
e_filippo
Quote:
Originally Posted by Spockster View Post
Ok, I misread the original post.

I wouldn't dive into coils until I checked for spark when it has stopped running..

If it has spark, then does it need gas, or have too much? Are the plugs wet, or dry, when it stops running.

As flitecontrol mentioned, could be POOGS. Will it restart if you open the gas cap?
The rear cylinder's plugs are wet when I pull them, the fronts are not. When the bike runs, it sputters on the rear cylinder until you get it up to about 4k, then it kicks on. As far as the vent goes, I wasn't finding where it's supposed to be on this tank. I have a spare tank that has a little 1/4" or so outlet on the tank right between the mounting screws for the gas cap, but the one on the bike doesn't have that. The cap has a small tube that fits right in the little outlet, so is that supposed to be on the tank?
03-31-2018 06:04 PM
Spockster Ok, I misread the original post.

I wouldn't dive into coils until I checked for spark when it has stopped running..

If it has spark, then does it need gas, or have too much? Are the plugs wet, or dry, when it stops running.

As flitecontrol mentioned, could be POOGS. Will it restart if you open the gas cap?
This thread has more than 10 replies. Click here to review the whole thread.

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

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