Front airbox drain hose - 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 07-23-2012, 05:42 PM Thread Starter
Member
 
Axelon20's Avatar
 
Join Date: Mar 2011
Location: western PA
Posts: 60
iTrader: (0)
 
Question Front airbox drain hose

This is sort of a continuation of a thread from the electrical forum
I have an engine stumble upon hard acceleration and above 55mph. After a lot of different tests and checks, I have determined that it is not electrical, but fuel/air related.
After removing and cleaning both the pilot and main jets, spraying Gumout up into the carbs through the float bowl drain holes, checking the float levels on both carbs, adjusting the fuel/air mixture screws about a dozen different ways, checking for and repairing all vacuum leaks that I could find, and Seafoaming the living crap out of the tank and the carbs, my next task will be the dreaded carb removal and clean/repair. However, upon removing the thermostat, I noticed a small vacuum type hose attached to the front bottom right of the airbox which comes out in front of the starter. It does NOT have any type of plug in the bottom, so in theory it could allow unfiltered air into the intake, not to mention that it could upset the vacuum flow of air as well. My question is, before I go further, should this hose normally have a plug in it?

1997 VN750. 34K miles
(so far).
MCCT mod
Coastered
Lithium Battery
Iridium sparkplugs
Tuxedo stator mod
TPE stator rebuild
Engine guards
R/R relocated, upgraded to Shindengen MOSFET
LED turnsignals & brakelights
Electronic flasher relay
K&N air filters
OPT7 LED headlight bulb
Headlight relay mod
Pirelli MT66 front & rear tires
Plexifairing 3 Windshield
Digital LED voltmeter
(Aluminum luggage rack,
Floorboards,
Heel-Toe shifter .....all homemade)
synthetic oil
Axelon20 is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 07-23-2012, 07:44 PM
Senior Member
 
kc2dgq's Avatar
 
Join Date: May 2010
Location: New Jersey
Posts: 3,350
iTrader: (13)
 
Garage
At the front of the airbox... on the bottom of the "L" shaped end...just below where the "ears" are joined to the box....that is a drain line and as far as I know it should routed down to the bottom of the bike and left open....so any water can drain out.

I wouldn't be too concerned about it sucking any unfiltered air into the system as the length and restricted diameter of the hose is not going to allow much unfiltered air into the airbox.....at least not as long as your filters are clean and properly oiled.
kc2dgq is offline  
post #3 of 12 (permalink) Old 07-23-2012, 07:48 PM Thread Starter
Member
 
Axelon20's Avatar
 
Join Date: Mar 2011
Location: western PA
Posts: 60
iTrader: (0)
 
Quote:
Originally Posted by kc2dgq View Post
At the front of the airbox... on the bottom of the "L" shaped end...just below where the "ears" are joined to the box....that is a drain line and as far as I know it should routed down to the bottom of the bike and left open....so any water can drain out.

I wouldn't be too concerned about it sucking any unfiltered air into the system as the length and restricted diameter of the hose is not going to allow much unfiltered air into the airbox.....at least not as long as your filters are clean and properly oiled.
I kind of figured that...just wanted a more experienced opinion. Well, I guess I'm going through with the carb job. Hell, I did the tuxedo stator mod with no problems....I should be able to do this, too.

1997 VN750. 34K miles
(so far).
MCCT mod
Coastered
Lithium Battery
Iridium sparkplugs
Tuxedo stator mod
TPE stator rebuild
Engine guards
R/R relocated, upgraded to Shindengen MOSFET
LED turnsignals & brakelights
Electronic flasher relay
K&N air filters
OPT7 LED headlight bulb
Headlight relay mod
Pirelli MT66 front & rear tires
Plexifairing 3 Windshield
Digital LED voltmeter
(Aluminum luggage rack,
Floorboards,
Heel-Toe shifter .....all homemade)
synthetic oil
Axelon20 is offline  
 
post #4 of 12 (permalink) Old 07-26-2012, 02:27 PM Thread Starter
Member
 
Axelon20's Avatar
 
Join Date: Mar 2011
Location: western PA
Posts: 60
iTrader: (0)
 
Well, I pulled the carbs and took them apart according to Clymers, but I can't find a damn thing wrong. Both carbs look like they were cleaned a week ago.( I use seafoam all the time, so maybe that explains it) The only thing I found was a little wear ring around the float needles where they meet the seats, and the seats are clean, too.
I brought them to work today to look at under 6X magnification and they hardly look worn at all other than the wear rings...one more so than the other, but no grooves that I can see or measure on our comparator. Also, the main and pilots jets, and the long, skinny needle jets are spotless. Now what??

1997 VN750. 34K miles
(so far).
MCCT mod
Coastered
Lithium Battery
Iridium sparkplugs
Tuxedo stator mod
TPE stator rebuild
Engine guards
R/R relocated, upgraded to Shindengen MOSFET
LED turnsignals & brakelights
Electronic flasher relay
K&N air filters
OPT7 LED headlight bulb
Headlight relay mod
Pirelli MT66 front & rear tires
Plexifairing 3 Windshield
Digital LED voltmeter
(Aluminum luggage rack,
Floorboards,
Heel-Toe shifter .....all homemade)
synthetic oil

Last edited by Axelon20; 07-26-2012 at 02:29 PM. Reason: forgot detail
Axelon20 is offline  
post #5 of 12 (permalink) Old 07-26-2012, 03:11 PM
Crap, I WAS in 5th gear.
 
Join Date: Sep 2011
Location: So. Cal
Posts: 500
iTrader: (1)
 
You sound lean on the main jet(s). Check the slide diaphragms for tears or pinholes, and make sure you don't have a binding slide. Also make sure the needles are smooth and straight (roll them on a piece of glass with the flange hanging off.)

I just noticed you have K&N air filters, which will be less restrictive than the stock ones- which could cause a slightly lean mixture. If there is no problem with your rubbers or needles, I don't see any other alternative at this point other than to upsize your main jets one increment. Messing with needle shims probably wouldn't have any impact, as you are above 3/4 throttle.

I *think* you can change your mains with the carbs on the bike. Some people have changed pilots, too, I tried but gave up because I didn't want to cross-thread the new pilot going in.

Don't know what else to tell you- that's about the limit of my knowledge and experience with CV carbs.
Kelly2001 is offline  
post #6 of 12 (permalink) Old 07-26-2012, 03:37 PM Thread Starter
Member
 
Axelon20's Avatar
 
Join Date: Mar 2011
Location: western PA
Posts: 60
iTrader: (0)
 
Quote:
Originally Posted by Kelly2001 View Post
You sound lean on the main jet(s). Check the slide diaphragms for tears or pinholes, and make sure you don't have a binding slide. Also make sure the needles are smooth and straight (roll them on a piece of glass with the flange hanging off.)

I just noticed you have K&N air filters, which will be less restrictive than the stock ones- which could cause a slightly lean mixture. If there is no problem with your rubbers or needles, I don't see any other alternative at this point other than to upsize your main jets one increment. Messing with needle shims probably wouldn't have any impact, as you are above 3/4 throttle.

I *think* you can change your mains with the carbs on the bike. Some people have changed pilots, too, I tried but gave up because I didn't want to cross-thread the new pilot going in.

Don't know what else to tell you- that's about the limit of my knowledge and experience with CV carbs.
Thanks for the info! I think one of the vacuum diaphragms has a leak, and I plan on replacing it (I don't know if that would cause this issue)...as for the slide diaphragms, how do you clean them up so that they don't bind?
I plan on going up to 135's for the main jets....can't hurt. I changed the pilots while the carbs were on the bike, and yes...it can be done. The mains, however, are fairly easy to get at and change on or off-bike.

1997 VN750. 34K miles
(so far).
MCCT mod
Coastered
Lithium Battery
Iridium sparkplugs
Tuxedo stator mod
TPE stator rebuild
Engine guards
R/R relocated, upgraded to Shindengen MOSFET
LED turnsignals & brakelights
Electronic flasher relay
K&N air filters
OPT7 LED headlight bulb
Headlight relay mod
Pirelli MT66 front & rear tires
Plexifairing 3 Windshield
Digital LED voltmeter
(Aluminum luggage rack,
Floorboards,
Heel-Toe shifter .....all homemade)
synthetic oil
Axelon20 is offline  
post #7 of 12 (permalink) Old 07-26-2012, 03:59 PM
Crap, I WAS in 5th gear.
 
Join Date: Sep 2011
Location: So. Cal
Posts: 500
iTrader: (1)
 
Quote:
Originally Posted by Axelon20 View Post
Thanks for the info! I think one of the vacuum diaphragms has a leak, and I plan on replacing it (I don't know if that would cause this issue)...as for the slide diaphragms, how do you clean them up so that they don't bind?
I plan on going up to 135's for the main jets....can't hurt. I changed the pilots while the carbs were on the bike, and yes...it can be done. The mains, however, are fairly easy to get at and change on or off-bike.
I remember you had an enricher diaphragm with a leak- I don't know if that could leak air and cause your mix to be lean at high throttle, but I don't think so.

As far as the slides, there's not much you need to do as long as there is no galling, they are clean, and move freely. If there are scuffs, maybe scotchbrite. The big diaphragms on the slides need to be air-tight. The whole slide assembly is crazy-expensive, but they are robust- yours are probably OK.
Kelly2001 is offline  
post #8 of 12 (permalink) Old 08-02-2012, 10:21 AM Thread Starter
Member
 
Axelon20's Avatar
 
Join Date: Mar 2011
Location: western PA
Posts: 60
iTrader: (0)
 
Well, I have ordered all the carb parts I needed, including a brand spanking new set of 138 main jets. Meanwhile, I have coastered the engine heads. Actually, I have made and installed the coasters and removed the vacuum valve crap, but I would like some opinions as to what I should use to plug the 1 inch diameter hole in the bottom of the airbox which now exists due to removal of the vacuum valve crap......any suggestions? Everything I have looks like it would fall out after about ten bumps in the road or so....

1997 VN750. 34K miles
(so far).
MCCT mod
Coastered
Lithium Battery
Iridium sparkplugs
Tuxedo stator mod
TPE stator rebuild
Engine guards
R/R relocated, upgraded to Shindengen MOSFET
LED turnsignals & brakelights
Electronic flasher relay
K&N air filters
OPT7 LED headlight bulb
Headlight relay mod
Pirelli MT66 front & rear tires
Plexifairing 3 Windshield
Digital LED voltmeter
(Aluminum luggage rack,
Floorboards,
Heel-Toe shifter .....all homemade)
synthetic oil
Axelon20 is offline  
post #9 of 12 (permalink) Old 08-02-2012, 07:59 PM
Senior Member
 
kc2dgq's Avatar
 
Join Date: May 2010
Location: New Jersey
Posts: 3,350
iTrader: (13)
 
Garage
I just left the hose in place and plugged the end of the hose. You can probably find a plastic end cap at home depot that fits and use some silicone to seal it up and hold it in place.
kc2dgq is offline  
post #10 of 12 (permalink) Old 08-09-2012, 03:39 PM
ass hole extaordinaire
 
new rider 9984's Avatar
 
Join Date: May 2012
Location: Sulphur Springs TX
Posts: 3,780
iTrader: (7)
 
Quote:
Originally Posted by Axelon20 View Post
Well, I have ordered all the carb parts I needed, including a brand spanking new set of 138 main jets. Meanwhile, I have coastered the engine heads. Actually, I have made and installed the coasters and removed the vacuum valve crap, but I would like some opinions as to what I should use to plug the 1 inch diameter hole in the bottom of the airbox which now exists due to removal of the vacuum valve crap......any suggestions? Everything I have looks like it would fall out after about ten bumps in the road or so....
i used the big marble out of a bag of marbles and stuck it i the end of the hose and left the hose in the air box its a tight fit but it seems to work fine
new rider 9984 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