Carb flooding or?? - 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 10 (permalink) Old 05-18-2011, 12:11 AM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
Carb flooding or??

Here we go again

I noticed a bit of yellow stain under the carbs on my newly painted engine. I pulled the carbs for the 6th? time and found a split fuel line where I tightened the hose clamp too tight I guess. In the meantime, I hung the carb over my bench just like it sits on the engine.

It leaked fuel.... out the carb bores.... BOTH of them.... where it connects to the intake tubes.

I pulled the carbs apart. The float lever is EXACTLY per the manual.... the seam in the float is mid way between the casting marks in the bowl (Right mark in the picture).

So I tweaked them a bit to LOWER the fuel level in the carb. Now the seam in the float is pointed at the lower casting mark. Reassembled everything, and it still leaks.

Any ideas? I can't tell exactly which port/hole it's coming from, but it appears to be above the butterflies on both carbs. It's dripping pretty regular, maybe once every 5sec with the carbs hanging, so it's A LOT.

Please help, I'm sick of this, and we're supposed to take the bike on the road Saturday morning.
Attached Thumbnails
Click image for larger version

Name:	05172233.jpg
Views:	116
Size:	81.1 KB
ID:	3746  

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 05-18-2011, 12:14 AM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
The picture shows my float setting per the manual BEFORE I tweaked it to lower the fuel level.

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
post #3 of 10 (permalink) Old 05-18-2011, 09:04 AM
Members who have donated towards server costs
 
JM2001's Avatar
 
Join Date: Mar 2011
Location: Rochester, New York
Posts: 1,803
iTrader: (1)
 
Quote:
Originally Posted by spiral_72 View Post
Here we go again

I noticed a bit of yellow stain under the carbs on my newly painted engine. I pulled the carbs for the 6th? time and found a split fuel line where I tightened the hose clamp too tight I guess. In the meantime, I hung the carb over my bench just like it sits on the engine.

It leaked fuel.... out the carb bores.... BOTH of them.... where it connects to the intake tubes.

I pulled the carbs apart. The float lever is EXACTLY per the manual.... the seam in the float is mid way between the casting marks in the bowl (Right mark in the picture).

So I tweaked them a bit to LOWER the fuel level in the carb. Now the seam in the float is pointed at the lower casting mark. Reassembled everything, and it still leaks.

Any ideas? I can't tell exactly which port/hole it's coming from, but it appears to be above the butterflies on both carbs. It's dripping pretty regular, maybe once every 5sec with the carbs hanging, so it's A LOT.

Please help, I'm sick of this, and we're supposed to take the bike on the road Saturday morning.
Missing or defective O-rings, defective float ( hole in it and not floating ), needle valve not seating properly or defective. In your pictue the float looks like it might be binding on the carb wall.

JM2001

" Loud Pipes Risk Rights "

2001 Vulcan 750
marbled
TOC upgrade on ACCT
Air/fuel mixture set to 2 1/2 out
rectifier relocated
splines lubed
iridiums
decals removed
upgraded mirrors
Pic up coil mod done
degoated
All LED lighting
Upgraded Mosfet rectifier
JM2001 is offline  
 
post #4 of 10 (permalink) Old 05-18-2011, 09:39 AM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
Quote:
Originally Posted by JM2001 View Post
Missing or defective O-rings, defective float ( hole in it and not floating ), needle valve not seating properly or defective. In your pictue the float looks like it might be binding on the carb wall.
I floated the floats while I had them out. They seem ok and do not have fuel in them when I disassemble the carb.... but good idea.

Do you have any specific o-rings in mind between the bowl and the venturii/throat of the carb? I don't remember any. I THINK that it's all passages in the casting at that point.

Binding? Great idea!

Needle valve not seating properly? That would sure do it. I guess I didn't consider that. The needle itself looks perfect and not worn at all as do the gaskets way up inside the seat. Maybe I can pull the carb apart and hang the center plate with the floats. I should be able to move the float by hand to the closed position and see if it seals off fluid.

Thank you for the great ideas. I'll report back

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
post #5 of 10 (permalink) Old 05-18-2011, 10:02 AM
Members who have donated towards server costs
 
JM2001's Avatar
 
Join Date: Mar 2011
Location: Rochester, New York
Posts: 1,803
iTrader: (1)
 
check diagram. Possible 92055

http://www.cheapcycleparts.com/model...semblies/73614

JM2001

" Loud Pipes Risk Rights "

2001 Vulcan 750
marbled
TOC upgrade on ACCT
Air/fuel mixture set to 2 1/2 out
rectifier relocated
splines lubed
iridiums
decals removed
upgraded mirrors
Pic up coil mod done
degoated
All LED lighting
Upgraded Mosfet rectifier
JM2001 is offline  
post #6 of 10 (permalink) Old 05-18-2011, 10:49 PM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
Quote:
Originally Posted by JM2001 View Post
The o-ring you mentioned is installed and looks great. The front carb was missing the metal ring/washer on top of the o-ring... I drilled the aluminum plugs two weeks ago myself, so it looks like it was missing from the factory. I'll see if I can find one tomorrow.

I hand actuated the floats. It cut off fuel just like it should. Then I looked around and found a small glass bowl that fit perfectly over the float chamber..... I run fuel into the chamber and the float come up and cut off fuel just like it should.... no problems there. See the attached image

You mentioned the float may be catching on the casting. It must be the angle of the picture, because it has plenty of room even if I force the float past the needle plunger. Was a good idea though!

I didn't find the problem yet. I DID break the mounting hole off the bowl though, so I'm pretty excited about that. If JB weld doesn't fix it, I guess I have a 500# paperweight until I can come up with $300+ for carbs.
Attached Thumbnails
Click image for larger version

Name:	05182020.jpg
Views:	76
Size:	82.2 KB
ID:	3751  

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
post #7 of 10 (permalink) Old 05-20-2011, 11:01 AM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
The JB weld seems to have worked....at least for now.

I pulled the carbs completely apart and checked over everything.... gaskets, o-rings, make sure nothing is missing. I installed the missing flat washer under the fuel mixture needle.

The carb is no longer leaking fuel out the bores. Unfortunately, I don't know what changed.... so I hung the carbs last night and filled them with fuel. If the fuel is still there tonight I'll call it good..... If not, I dunno what I'm going to do.

After JM2001 mentioned those things, I studied the carb to see HOW fuel flows:

It sits in the bowl, level regulated by the float. That seems to work, illustrated by the glass bowl picture above.

It leaves the bowl into the bottom chamber with the jets through three holes in the side of the bowl: Two low and one high hole in the center.

From there, the fuel looks like it sits in the jet's chamber until engine vacuum draws it out through the three possible passages... and idle post, mid-range jet, and high speed jet (my terminology may not be right).

Anyways, the point is: I can't figure out how the heck fuel is leaving the bowl/jet chamber and dripping down the bore of the carb and into the engine!

If it's holding fuel tonight, I'll install the carbs again. If not, who knows?

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
post #8 of 10 (permalink) Old 05-21-2011, 01:17 AM
Member
 
Join Date: Apr 2011
Location: San Clemente, CA
Posts: 40
iTrader: (0)
 
Quote:
Originally Posted by spiral_72 View Post
After JM2001 mentioned those things, I studied the carb to see HOW fuel flows:

It sits in the bowl, level regulated by the float. That seems to work, illustrated by the glass bowl picture above.

It leaves the bowl into the bottom chamber with the jets through three holes in the side of the bowl: Two low and one high hole in the center.

From there, the fuel looks like it sits in the jet's chamber until engine vacuum draws it out through the three possible passages... and idle post, mid-range jet, and high speed jet (my terminology may not be right).
Spiral_72: I've had issues with my Carbs for a while, with fuel spilling out the overflow/vent tube into the right ear...I thought it was always a stuck float and have tried many things to alleviate that...but you talking about fuel flow, I'm wondering could my issue be a clogged Jet?

1993 VN750 stock
knicol is offline  
post #9 of 10 (permalink) Old 05-23-2011, 11:55 AM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
Quote:
Originally Posted by knicol View Post
Spiral_72: I've had issues with my Carbs for a while, with fuel spilling out the overflow/vent tube into the right ear...I thought it was always a stuck float and have tried many things to alleviate that...but you talking about fuel flow, I'm wondering could my issue be a clogged Jet?
Ah, in my opinion I would not suspect a clogged jet.... IMO, depending what jet was clogged, you would have a flat spot in the engine RPM in that jet's range.... that's assuming the other carb is working perfectly.

I can't imagine what would make the bowl vent spit fuel. That is such a LONG distance for fuel to travel (and all up hill) that I doubt you problem is a stuck float / overfilled bowl or plugged jet. If I were to guess.... aka if I had that problem, I'd work under the assumption that fuel is being blown through the bowl vent.... maybe by backfiring, bad cam timing, plugged exhaust ummmmmm, maybe your engine firing out of time.

and that's MY inexperienced opinion.

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery
spiral_72 is offline  
post #10 of 10 (permalink) Old 05-23-2011, 12:12 PM Thread Starter
Senior Member
 
spiral_72's Avatar
 
Join Date: Jul 2009
Location: Spartanburg, SC
Posts: 130
iTrader: (0)
 
Well, I (we) took the bike on a 300+ mile trek on Saturday. She run nearly perfect (not carb related) so my results / thoughts are as follows:

The split fuel line under the filter where I tightened the hose clamp too tight was the reason for the leaking fuel external of the carb.

Fuel leaking internally and into the intake on BOTH carbs was an interesting matter. I pulled everything apart, check the floats and checked jets, passages etc with 20psi air. Checked gaskets and installed the missing flatwasher under the mixture needle. Once all back together, the problem was gone. I dunno why, or what was wrong, but it seems perfect now. I hate when I fix stuff without knowing how... it just leaves a nagging doubt that it'll return.


Anyways, we used about 6.1gal of fuel on a 315 mile trip fully loaded, me, my wife and a bag...... just short of 400#. According to the GPS my speedo is 3mph off at 60mph (with the oversize tire)or 5% off, so it reads 15miles farther on a 315mile trip..... so figuring that we got 49.2mpg!! Not too bad eh?

It's nice she's running correctly again.

1992 VN750 dark blue / black - stock
Cobra exhaust
Oversized front tire to correct speedo & improve handling
New stator and Vreg 4/11
Sealed battery

Last edited by spiral_72; 05-23-2011 at 12:17 PM.
spiral_72 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