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1993 XV750 Carburetors Flooding (Tennessee cyclebum) [SOLVED]

Posted: Mon Nov 25, 2019 8:29 pm
by cyclebum57
Hey Ya'll, Joined this forum to get help on my bobber. I have a 93' 750 Virago that I have lowered and raked. I will have to get some pics for ya. This is my second build. My first one was a 85 700. I am having some problems with my carbs which is testing my will to finish this bike. I sold my first bobber and regretted it. I ride a Harley for those long rides, but I loved my bobber for local riding on back roads. It was easy to handle. I could ride the curves or take off thru a field. It just handled great. The one I am building now has a problem with flooding. Here is what I don't get. They flood on the bike, but when I hung a temp tank up and hooked up my carbs one at a time, they worked fine. Hooked them together and they started flooding. Any help, I would sure appreciate it.

Re: 1993 XV750 Carburetors Flooding (Tennessee cyclebum)

Posted: Tue Nov 26, 2019 9:24 am
by ViragoJoe
cyclebum57 wrote:
Mon Nov 25, 2019 8:29 pm
Hey Ya'll, Joined this forum to get help on my bobber. I have a 93' 750 Virago that I have lowered and raked. I will have to get some pics for ya. This is my second build. My first one was a 85 700. I am having some problems with my carbs which is testing my will to finish this bike. I sold my first bobber and regretted it. I ride a Harley for those long rides, but I loved my bobber for local riding on back roads. It was easy to handle. I could ride the curves or take off thru a field. It just handled great. The one I am building now has a problem with flooding. Here is what I don't get. They flood on the bike, but when I hung a temp tank up and hooked up my carbs one at a time, they worked fine. Hooked them together and they started flooding. Any help, I would sure appreciate it.
Seeing pictures of your bike to see how you have lowered and raked it would be a necessity.

Flooding Carburetor(s) are usually always due to float settings in the Carburetor(s)

Note: Your Carbs are tilted and by lowering or raking, you can be changing the float angle causing the flooding condition. Also, the temp tank doesn't have the same gravity pressure pressing fuel down like the main fuel tank does. Causing the needle and seat to leak, due to the higher gravity pressures.

See this video regarding carburetor angle and float settings: https://www.youtube.com/watch?v=Xj220oY26Yo

Re: 1993 XV750 Carburetors Flooding (Tennessee cyclebum)

Posted: Tue Nov 26, 2019 8:25 pm
by cyclebum57
Found the problem with the flooding. I am guessing that the 85 I bobbed before had a slightly different carb than this 93. I read something about 88 and up carbs being the same. With that being said, I looked the carbs over again and unplugged the vent pipes that would have hooked to the charcoal canister. I have no emissions on this bike. As soon as I unplugged the vent pipes, the flooding stopped. I am thinking air was getting trapped in the bowls with the vent pipes plugged and wasn't allowing the needles to close tight to stop gas flow. I am going to put the carbs back on and see what happens. Let ya'll know when I get it done. I tried to add a pic of my bike, but it says file is to big. Any suggestions. I am not a computer whiz.

Re: 1993 XV750 Carburetors Flooding (Tennessee cyclebum)

Posted: Tue Nov 26, 2019 11:01 pm
by ViragoJoe
cyclebum57 wrote:
Tue Nov 26, 2019 8:25 pm
Found the problem with the flooding. I am guessing that the 85 I bobbed before had a slightly different carb than this 93. I read something about 88 and up carbs being the same. With that being said, I looked the carbs over again and unplugged the vent pipes that would have hooked to the charcoal canister. I have no emissions on this bike. As soon as I unplugged the vent pipes, the flooding stopped. I am thinking air was getting trapped in the bowls with the vent pipes plugged and wasn't allowing the needles to close tight to stop gas flow. I am going to put the carbs back on and see what happens. Let ya'll know when I get it done. I tried to add a pic of my bike, but it says file is to big. Any suggestions. I am not a computer whiz.
Yes sir, carbs were different in 1985 they were Hitachi. In 1988 onward they were changed to Mikuni.

Read this topic regarding the venting pipes on the carburetors. If these are the vents you said you blocked, no wonder you had problems. viewtopic.php?f=44&t=1054

Things should be left as they are. Any changes made from standard conditions to these bikes creates consequences. These are things that make it almost impossible to diagnose, such as this, and we aren't aware were made. As plugging the vent pipes.

Bikes equipped with charcoal canisters are for the state of California, due to different emission standards.

How does a CV Carburetor work - Quick and simple explanation - Video
https://www.youtube.com/watch?v=IBFq9nHVmks

If you want to really understand these carburetors read these articles below:

Virago Carburetor CV CV (Constant Velocity)
https://www.viragohelp.com/virago-carburetor-cv/

Virago Hitachi Carburetors
https://www.viragohelp.com/virago-hitachi-carburetors/
The first paragraph: "(Note: the word “carburetor” is a French word. In English it refers to the fuel mixture dispenser residing near a cylinder. However, you should be aware that the meaning of this word in the native French language is quite different. In French it means: “Don’t mess with me”).

Virago Mikuni Carburetors
https://www.viragohelp.com/virago-mikuni-carburetors/