Who's the "CARB GURU" - 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 12 (permalink) Old 04-21-2011, 06:19 PM Thread Starter
Fire Axe Man
 
Join Date: Apr 2011
Location: wisconsin
Posts: 61
iTrader: (2)
 
Who's the "CARB GURU"

pulled my carbs apart and found i couldn't easily move the small diaphram, didn't move at all... should it move in and out easily? everything else in carbs now moves great and works properly... just can't idle bike and starts real hard, (ether) re-jeting tomorrow to compensate for ear shave, but wanna make sure about this small diaphram while carbs are out tommorow as well...

Just can't leave well enough alone...

86 vn750
Ears Shaved
Custom Exhaust
Custom Seat
Hardtail 3 1/2" drop rear
Custom turn signals
15" apes
Custom grips
Custom forward controls
Custom paint
many more mods to come
Mike23Impala is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 04-21-2011, 06:41 PM
Members who have donated towards server costs
 
denny6006's Avatar
 
Join Date: Mar 2009
Location: InezKY pop.600
Posts: 5,236
iTrader: (9)
     
Garage
Quote:
Originally Posted by Mike23Impala View Post
pulled my carbs apart and found i couldn't easily move the small diaphram, didn't move at all... should it move in and out easily? everything else in carbs now moves great and works properly... just can't idle bike and starts real hard, (ether) re-jeting tomorrow to compensate for ear shave, but wanna make sure about this small diaphram while carbs are out tommorow as well...
that is the air cut valve it should have a rather stiff spring behind it,it may be the brass part is stuck to the aluminum of the carb body if you are talking about the one on the side of the carb.Don't ask me what it does but it would be working at a high vacuum situation such as at idle or when you close the throttle fast.

and I am by no means a carb guru or anything else as far as that goes.but they should move.




If you see it on my bike I did it
VROC#30324
92 vn750(sold)
Current ride 05 1500 Classic FI
lovin' the new scoot



Quote:
"When all is said and done,usually more is said than done" UNK
Click on one x and drag to the other to read between them.

Psalm 40:1...
XI waited patiently for the Lord; and he turned unto me, and heard my cry. X

Last edited by denny6006; 04-21-2011 at 06:43 PM.
denny6006 is offline  
post #3 of 12 (permalink) Old 04-21-2011, 06:58 PM Thread Starter
Fire Axe Man
 
Join Date: Apr 2011
Location: wisconsin
Posts: 61
iTrader: (2)
 
beautiful so shouldn't have anything to do with my isuue... but may cause backfiring upon deceleration... im a car guru NOT a bike wizz...

Just can't leave well enough alone...

86 vn750
Ears Shaved
Custom Exhaust
Custom Seat
Hardtail 3 1/2" drop rear
Custom turn signals
15" apes
Custom grips
Custom forward controls
Custom paint
many more mods to come
Mike23Impala is offline  
 
post #4 of 12 (permalink) Old 04-21-2011, 08:14 PM
Member
 
Join Date: Nov 2010
Location: RI
Posts: 97
iTrader: (2)
 
@ Denny The manuals call that thing the coasting enricher, not that I mean to correct you. I think it supplies extra fuel when engine braking, since the idle circuit doesn't provide enough fuel at higher rpm's. With the butterfly valve closed, the slide drops and the main jet doesn't let out any fuel.

@Mike That air cutoff/coasting enricher would cause decel backfiring if it doesn't function and leaves you with a lean coasting mixture. Remember that it works against the spring, so you want to pull on it. As I recall that thing is a little tricky to grab and pull. Have you played with the one on the other carb for comparison?

I wouldn't pin the backfiring during decel on that diaphragm quite yet. It could be responsible, but if you have done an ear shave without re-jetting, you will be running lean. If the plugs covering the mixture screws are still in the carbs, drill them out while it's easy. The bike is tuned lean when stock and MawKaw doesn't want you to mess with the mixture. Bigger jets will compensate, but you still might need a little help from the mixture screws.
Bazooka_Luca is offline  
post #5 of 12 (permalink) Old 04-22-2011, 01:24 AM
Banned
 
Join Date: Dec 2010
Posts: 448
iTrader: (3)
 
When I pulled my carbs, I tore them down and went through them. The coasting enricher diaphrams could be stuck in the carbs, or just sticky. I used a metal dental pick with an angled tip to gently get under the edge of the diaphram, and pull it up to get a hold of it with my fingers. When you get them out, check to see if they are stiff. They should be fairly soft and flexible, not too stiff. If they snap or are too stiff, it's time to replace them.
I took some 2000 grit sand paper, and GENTLY sanded them to clean the brass up, and they work great now, slide in and out like they should.
RakerBill is offline  
post #6 of 12 (permalink) Old 04-22-2011, 06:01 PM Thread Starter
Fire Axe Man
 
Join Date: Apr 2011
Location: wisconsin
Posts: 61
iTrader: (2)
 
they didn't move at all... and don't still, but as for riding lean i have no cables for throttle yet so not riding just operating by hand to try to get it to run,... today i hit the starter button it back fired so loud i thought it blew thew pipes off the bike, then fired up and runs like a dream, starts every time now and idles great, no smoke, no backfires, just purs beautiful... jets come in tomorrow to re-jet and will mess with the fuel mixture screws and try to get these coasting enrichers to work properly again... this one is a tough one trying to work out 100 problems at once from the bike sitting for 7 years... it will be an interesting first ride next weekend maybe, all cables and ordered parts come in friday 4-29-11 or 5-1-11 cant hardly wait!!! few new pics in my profile for those interested in how the project is coming...

P.S. what setting do you have the fuel pet-cock at to ride, On or Pri? seems to run out of fuel "On" pet-cock is very clean and screens all in good shape... havn't tried reserve... pri seems to pour fuel in...

Just can't leave well enough alone...

86 vn750
Ears Shaved
Custom Exhaust
Custom Seat
Hardtail 3 1/2" drop rear
Custom turn signals
15" apes
Custom grips
Custom forward controls
Custom paint
many more mods to come
Mike23Impala is offline  
post #7 of 12 (permalink) Old 04-22-2011, 11:30 PM
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Quote:
Originally Posted by Mike23Impala View Post
P.S. what setting do you have the fuel pet-cock at to ride, On or Pri? seems to run out of fuel "On" pet-cock is very clean and screens all in good shape... havn't tried reserve... pri seems to pour fuel in...
PRIme will pour fuel in without any vacuum applied to the center nipple on the petcock. That function on yours is working properly.

ON and REServe settings require vacuum applied to the middle nipple to move a diaphram for the fuel to flow.
The PRIme position is only found on models from 1985 to `88 or `89.
Later models have OFF, ON and REServe.

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html

Last edited by OlHossCanada; 04-22-2011 at 11:35 PM.
OlHossCanada is offline  
post #8 of 12 (permalink) Old 04-23-2011, 12:37 AM
Senior Member
 
Join Date: Mar 2005
Location: Channelview, TX
Posts: 748
iTrader: (1)
 
Air cut diaphragm and coasting enrichment diaphragm are different words for the same part; depends on where you look in the manual and parts diagrams as to what it's called. The brass plunger prolly has varnish buildup/gum on it; clean up as RakerBill said above, or use 0000 steel wool, and flush out the opening it goes into with carb cleaner.

The petcock issue has me puzzled, unless the vacuum hose isn't hooked up to the nipple on the left carb, or the petcock is gummed up, too. The vacuum port on it may be clogged.

J.D.
Kerrville, TX
'95 Vulcan 750 "Therapy II",
aka "Raggedy Ann"
'95 VN750 project
'03 VN800B "The Little Black"
'04 VN800E Drifter project
'93 VN1500A custom project
VROC #16185
GCVROC #33

Photo album: http://www.flickr.com/photos/leekayd/sets
J.D. is offline  
post #9 of 12 (permalink) Old 04-23-2011, 09:45 AM Thread Starter
Fire Axe Man
 
Join Date: Apr 2011
Location: wisconsin
Posts: 61
iTrader: (2)
 
i have the vaccume line hooked up from the left carb to tank and right vaccume on carb is caped off, but the center to lines are vaccume as well? or breathers? earshave said put a filter on these but if there vaccume that would be a " vaccume leak" to simply put a filter on them... this problem seemed to start after ear shave i believe...

Just can't leave well enough alone...

86 vn750
Ears Shaved
Custom Exhaust
Custom Seat
Hardtail 3 1/2" drop rear
Custom turn signals
15" apes
Custom grips
Custom forward controls
Custom paint
many more mods to come
Mike23Impala is offline  
post #10 of 12 (permalink) Old 04-26-2011, 02:26 AM
Senior Member
 
Join Date: Mar 2005
Location: Channelview, TX
Posts: 748
iTrader: (1)
 
Quote:
Originally Posted by Mike23Impala View Post
i have the vaccume line hooked up from the left carb to tank and right vaccume on carb is caped off, but the center to lines are vaccume as well? or breathers? earshave said put a filter on these but if there vaccume that would be a " vaccume leak" to simply put a filter on them... this problem seemed to start after ear shave i believe...
The two upper hoses that tee into one are the float chamber vents; the one hose usually goes to the right ear, or on older bikes to the nipple on the cover for the tank sending unit. In the earshave, it gets a filter to keep bugs and dirt out; it's not a vacuum hose.

If it was running well before you started on the earshave, it's doubtful the petcock is a problem.

Until you've got near the right jets, both main and pilot, in the carbs, and your throttle cables hooked up, you're kinda pissin' in the wind. However, it should still idle. Check that the idle adjustment is turned in enuff that the throttle butterflies are just starting to open; should be around a turn and a half after the end of the adjuster touches the arm. There's a newer thread that shows that part futher up the list here. (Never mind; I see where you posted there)

Jim

J.D.
Kerrville, TX
'95 Vulcan 750 "Therapy II",
aka "Raggedy Ann"
'95 VN750 project
'03 VN800B "The Little Black"
'04 VN800E Drifter project
'93 VN1500A custom project
VROC #16185
GCVROC #33

Photo album: http://www.flickr.com/photos/leekayd/sets

Last edited by J.D.; 04-26-2011 at 02:28 AM.
J.D. 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