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1983 XV920 New to me, but need help on current carb configuration [CLOSED]

Have a question about fixing something on a Yamaha Virago XV920? Post it here!

Moderators: ViragoJoe, choppin

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ViragoJoe
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What Virago you Own: 1996 Virago Special XV1100SH
"Never ride faster than your Guardian Angel can fly!!"

Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by ViragoJoe » Mon Aug 19, 2019 10:11 pm

zero420 wrote:
Mon Aug 19, 2019 7:38 pm
Hey Joe. Thank you for all of your help. I have time this weekend and I plan on getting to the carbs and seeing how things are inside. I do have one question though that is still bothering me.

In the images posted, I see that on the left side there is a line from the gas tank to the carb and to the boot, however this is not the same on the right where it only connects to the carb, and not the carb boot.

My question is: Why would there be a gas line directly into the boot? I see from other virago post and videos on the carb cleaning process that both boots AND carbs are feed from the petcock.

Now, I realize that this is a modified virago, and the carbs and alterations that I don't know of as of yet. BUT, I haven't personally seen a set of carb and boots that are feed quite like this. Any education you could give me on why the boots are feed fuel, I would greatly appreciate it.
There should not be fuel lines connected directly to the carb boots. Vacuum lines are more like it. But, not fuel lines

Some petcocks are vacuum operated. When the bike is turned off the lack of vacuum closes the petcock.

Virago Fuel systems:
https://www.viragohelp.com/virago-fuel-systems/
ViragoJoe
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)

zero420
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Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by zero420 » Tue Aug 20, 2019 7:04 pm

ViragoJoe wrote:
Mon Aug 19, 2019 10:11 pm
zero420 wrote:
Mon Aug 19, 2019 7:38 pm
Hey Joe. Thank you for all of your help. I have time this weekend and I plan on getting to the carbs and seeing how things are inside. I do have one question though that is still bothering me.

In the images posted, I see that on the left side there is a line from the gas tank to the carb and to the boot, however this is not the same on the right where it only connects to the carb, and not the carb boot.

My question is: Why would there be a gas line directly into the boot? I see from other virago post and videos on the carb cleaning process that both boots AND carbs are feed from the petcock.

Now, I realize that this is a modified virago, and the carbs and alterations that I don't know of as of yet. BUT, I haven't personally seen a set of carb and boots that are feed quite like this. Any education you could give me on why the boots are feed fuel, I would greatly appreciate it.
There should not be fuel lines connected directly to the carb boots. Vacuum lines are more like it. But, not fuel lines

Some petcocks are vacuum operated. When the bike is turned off the lack of vacuum closes the petcock.

Virago Fuel systems:
https://www.viragohelp.com/virago-fuel-systems/
Thanks for the info. it is much appreciate and I do enjoy the education. I feel like you might be the Virago Godfather on the net haha.

It looks like the petcock has 2 ports (I think that's how they'd be quantified) one for fuel and one a vacuum. the fuel line feeds both carbs after the T split in the line. Though, only one vacuum line is attached to the carb on the left (viewed while sitting on the bike) With that in mind, shouldn't both carb boots have a vacuum line?
From Utah, Eagle Mt. USA
83 920 Virago
07 YZF600R
04 YZ45F

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ViragoJoe
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What Virago you Own: 1996 Virago Special XV1100SH
"Never ride faster than your Guardian Angel can fly!!"

Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by ViragoJoe » Wed Aug 21, 2019 6:48 am

"Virago Godfather" Oh No! There are real Guru's of these bikes that I have learned from that have forgotten more than I'll ever know. I am not worthy to polish theIr boots!

As for the vacuum lines. XV1000 and XV1100's I know for sure that the front and rear carburetors are connected together via vacuum lines. Done for a reason. Although these models do not have petcocks they do have a pressure sensor operated by vacuum. When synchronizing the carburetors the front carburetor vacuum line is removed from the carburetor boot and that line gets plugged with something to maintain vacuum. The port on that front boot is now fitted with a manometer hose. Then on the rear carburetor there are two ports. One with a blind plugged that is removed and the other end of the manometer goes on that port. The other port goes to a "T" that connects to that front carburetor vacuum line and also connects to the Pressure sensor. So, when that front carburetor is isolated from the system the rear carburetor runs the pressure sensor. Hope that makes sense.

I'm not that familiar with XV920's to know if their carburetors are connected together in the same manner for any reason. I imagine they would be for if you isolate one of the carburetors from the vacuum system. The other carburetor would need to activate the vacuum controlled petcock or the bike would stop running once the carb float bowls ran empty.

Since your bikes fuel system may have been modified. It can run and activate the fuel petcock with just one carburetors vacuum line. Where a problem may arise is when you try to synchronize the carburetors. Then you may have to develop a method or work around to get the carbs synchronized. Outside of that. Your bike will run with the one vacuum line to the petcock.
ViragoJoe
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)

zero420
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Joined: Tue Aug 06, 2019 4:34 pm
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Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by zero420 » Fri Aug 23, 2019 4:07 pm

Thank you very much for your help, again, ViragoJoe! Your explanation and education is very helpful and appreciated.

I forgot to post a pic of the the while bike. Here's one :)

https://imgur.com/ZSKdHBb
From Utah, Eagle Mt. USA
83 920 Virago
07 YZF600R
04 YZ45F

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ViragoJoe
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Posts: 1067
Joined: Wed May 20, 2015 10:36 am
What Virago you Own: 1996 Virago Special XV1100SH
"Never ride faster than your Guardian Angel can fly!!"

Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by ViragoJoe » Fri Aug 23, 2019 4:14 pm

zero420 wrote:
Fri Aug 23, 2019 4:07 pm
Thank you very much for your help, again, ViragoJoe! Your explanation and education is very helpful and appreciated.

I forgot to post a pic of the the while bike. Here's one :)

https://imgur.com/ZSKdHBb
Very Nice!!
ViragoJoe
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)

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Yogi4
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What Virago you Own: '92 Virago XV750D

Re: 1983 XV920 New to me, but need help on current carb configuration.

Post by Yogi4 » Sun Aug 25, 2019 9:40 am

I was having issues with mine as well. It would only run for short test rides up and down the street before it acted like it was running out of gas. I'd let it set for a couple of minutes then it would fire back up and I'd be able to make it back home. And this was after rebuilding both carbs. So I just said "Screw it!!", I got a manual petcock so it doesn't have to opperate off of vacuum (just remember to turn it to the "off" position when done riding), got new manifold boots and replaced all the fuel lines and ran them the way I saw fit. It runs great and am riding long distances now!! I think doing all that was under $35 from eBay. Best to do it all at once because getting those carbs off are a pain!!!
"May the good news be yours!" - Les Nessman

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