Kawasaki VN750 Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
68 Posts
Discussion Starter #1
Here's my situation:

I have a 86' Vulcan that has been sitting back home in my parents garage for around 5 years. I got up and left for Arizona and i periodically come back and do some work on it but have never got it to fully start because of the same problem! Now I'm back home going at it again. I took apart the carb numerous time and cleaned everything over and over and made sure everything was in order. Yet like the all my previous attempts i encountered gas flooding everywhere while trying to get the bike to turn over. :doh: My gut feeling is that gas is just pouring in the carb. not being controlled perhaps because of a worn needle. However when looking at the needle it does not look too worn at all. So before i go spending money on my bike back home i want to get some suggestions on what this might exactly be.

The Problem:

Flooding of Carbs. through Left Air Box while getting the bike to turn over.

Has anyone encountered this problem? Any help will be greatly appreciated.
 

·
Premium Member
Joined
·
5,236 Posts
Here's my situation:

I have a 86' Vulcan that has been sitting back home in my parents garage for around 5 years. I got up and left for Arizona and i periodically come back and do some work on it but have never got it to fully start because of the same problem! Now I'm back home going at it again. I took apart the carb numerous time and cleaned everything over and over and made sure everything was in order. Yet like the all my previous attempts i encountered gas flooding everywhere while trying to get the bike to turn over. :doh: My gut feeling is that gas is just pouring in the carb. not being controlled perhaps because of a worn needle. However when looking at the needle it does not look too worn at all. So before i go spending money on my bike back home i want to get some suggestions on what this might exactly be.

The Problem:



Flooding of Carbs. through Left Air Box while getting the bike to turn over.

Has anyone encountered this problem? Any help will be greatly appreciated.
you are probably right about gas getting by the needle valve and you need to check the seat on the carb that is flooding too,I fought with one of these problems and pulled the carbs of 3 times on a customer bike that had been to another shop.A scratch on a needle valve seat smaller than a human hair will keep the needle from seating and let gas pour by it . If you don't find anything wrong with the seat,buy anew needle even if it doesn't look worn.As these carbs have side hung floats I think you can hold them in the normal operating position on the bench with the bowl off and hook up a gravity feed bottle to the flooding carb and move the float up and down manually and see if it is shutting off the fuel flow ,just use some type of nonflamable liquid when testing this way,you could just need to adjust the float level.I know this can be tested on the bike with a clear tube but if it is wrong they have to come off anyway,I ended up changing the middle of the carbs on the bike I was talking because some one" cleaned the seat" with something sharp.Good Luck,Denny
 

·
Registered
Joined
·
68 Posts
Discussion Starter #6
When i had the carbs out i did not notice any rubber seats for the float needls, and don't see them on the parts diagram,
also wondering,
As I checked the float height, I blew threw the fuel line to see where the needle would plug and stop me from blowing into the tubing, it stopped me from blowing into it, could the needles be bad?, could fuel still pass if it stopped air?
 

·
The Professor
Joined
·
3,147 Posts
When i had the carbs out i did not notice any rubber seats for the float needls, and don't see them on the parts diagram,
also wondering,
As I checked the float height, I blew threw the fuel line to see where the needle would plug and stop me from blowing into the tubing, it stopped me from blowing into it, could the needles be bad?, could fuel still pass if it stopped air?
There are no rubber seats, do the float needles look worn? If so replace, clean thoroughly and fill fuel lines and check for leaks before you install.

I would replace the float and jet cover o-rings, they are prone to leak once removed on older bikes.
 

·
The Professor
Joined
·
3,147 Posts
Do you by any chance have the carb vent hose hooked to the nipple on the right front of the surge tank?
 

·
Premium Member
Joined
·
5,236 Posts
Lance is correct our bikes do not have rubber seats they are tapered and made of brass and are easily scratched by sharp or hard objects,It sounds like yours are sealing but some times liquid will leak past when you can physically hold them up,for two different reasons 1.You may be exerting more force than the float can and forcing a "false seal"2. I think Lance has pointed this out in the previous post,you can have a damaged or out of adjustment float or needle,valve. While a needle can look perfect to the naked eye the Viton tip may be hardened or have damage or wear not visible to the naked eye,or the taper may have a ring built up around the sealing surface that you can not see.when in doubt or having an obvious flooding problem.I would replace the needle valve and float on the front or rear carb ,whichever cyl. was flooding out .Do you have the exhaust crossover removed,so you can be sure which is the offending cylinder, and are you sure it is a fuel problem ?Lots of times we assume we have carb problems when it may be a symptom rather than an underlying cause. I was taught to remember C.I.F. it means to check in this order- 1.Compression-no engine without the proper compression will burn fuel efficiently. 2.Ignition-A faulty ignition system ,on our bikes this is the ignitor,coils ,wires ,plugs and all wires and switches and connections in the circuit, if these components are not working properly improper or no combustion will occur.3.Fuel.check all components of the fuel delivery system,Tank,petcock,fuel lines,vacuum lines and the carbs.Too many times we (me included) will make the leap to carbs,before checking the first two items for problems and cause ourselves more problems before finding the original problem and masking the underlying problem making it harder to find.
 

·
Registered
Joined
·
68 Posts
Discussion Starter #10
.I would replace the needle valve and float on the front or rear carb ,whichever cyl. was flooding out .

So I should replace the floats also???
I held them under water for a few seconds and did see any water in them, so they didn't leak,

Also what would be the best (easiest) way to figure out which cylinder is flooding?
 

·
Premium Member
Joined
·
5,236 Posts
.I would replace the needle valve and float on the front or rear carb ,whichever cyl. was flooding out .

So I should replace the floats also???
I held them under water for a few seconds and did see any water in them, so they didn't leak,

Also what would be the best (easiest) way to figure out which cylinder is flooding?
pull the spark plugs and see which in cylinder they are soaking if soaking wet,if your float is good you don't need to replace it just the needle
 
1 - 11 of 11 Posts
Top