84 XV700 Running Rich? (Secane Pa Delaware County)

Have a question about fixing something on a Yamaha Virago XV700? Post it here!

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ViragoJoe
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What Virago you Own: 1996 Virago Special XV1100SH

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by ViragoJoe » Tue Apr 26, 2022 10:42 am

Anlard wrote:
Tue Apr 26, 2022 9:58 am
Hello again. First of all, a shout-out to Dave Denowh for the TCI rebuild. He did it over the weekend and I got it on Monday.
Here's the update - - - with the new TCI unit installed the bike starts up from cold immediately, no tach flutter. There IS some "spitting" from the exhaust at idle but, after driven, that all goes away. The bike pulls smoothly and runs fine. The only issue now is the idle will slowly rise after warm and, when adjusted down, will tend to die, so the adjustment is always being fiddled with. Also, it is hard to start when warm. I know this seems like the pilot screws need adjustment (they are 3x out right now) and I'll try that "running one one cyl at a time trick" to try and pin that down but, other than that, are there any suggestions on the idle issue and the hard start when warm I should look at? This has been a great winter project and I am SO close!
Thx
Anlard,
I'll try that "running one one cyl at a time trick" to try and pin that down
That's not really a trick. There's no other way to set the Pilot Screws (think about it). Yamaha doesn't indicate in the Factory Manuals on what the average turns out from a soft seat are for the Pilot Screws. Turn values that you may have come across are settings folks have found that work best for them . Every Virago is rather unique on to itself, due to age. There are various things that can throw things off.

For Example:
"Running rich, running lean

I get lots of "black plug" questions, and while I cover a lot of the reason for this in the carb articles, I decided to do a list here (and on lean running as well)

Why carbs run rich:

--Air cleaner dirty
--Fuel too high in float bowls
--float valves leaking
--floats out of adjustment
--floats leaking (taking on fuel, going "heavy")
--Pilot screws adjusted too rich
--Coasting enrichers (where found) not working properly (cutting off air to pilot circuits)
--Worn needles and/or needle jets (ovalling)
--Starter plungers leaking

Why carbs run lean:

--Air leaks (between carb and engine)
--carbholders
--vacuum lines
--Pilot screws adjusted too lean
--Fuel levels too low in bowls
--floats out of adjustment
--Diaphragms blown
--slides not rising properly
--Fuel supply problems
--Seals around butterfly shafts leaking air (mainly affects idle)".

Here's an excerpt below taken from an article on this website:

A NOTE ON COIL WINDINGS

The wire windings in coils touch each other. However, they have an insulating skin on them and so one winding is insulated from the next.

I know of only two things that can happen to windings. The wires can break causing an open circuit or "open". Or the insulation between windings can break down, allowing the actual conductors to touch--which allows current to jump across windings. This can be called a "short". In testing a coil, an "open" will show up as lack of "continuity" or an infinite resistance condition--no current gets through. A "short' will show up as an out of spec resistance number (probably lower) as current jumps across windings. The only other point to keep in mind is that metal (and wire is metal) expands a little when hot. Occasionally windings will start touching and "short" when they heat up, whereas they will test O.K. when cold.

Sound familiar? Do a Coil Resistance Test. First Cold and then again when HOT. See if you get a difference in Resistance Values.
ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)


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Anlard
Posts: 14
Joined: Thu Apr 14, 2022 8:10 pm
Location: Secane Pa Delaware County
What Virago you Own: '84 XV 700

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by Anlard » Tue Apr 26, 2022 4:58 pm

One more question on the pilot screws on the carbs. Can someone confirm for me the sequence of the screw, the spring, the tiny flat washer and the rubber "o" ring? I may have messed that up on the rebuild. The repair manual shows the screw going into the carb with the spring first, then the "o" ring, then the screw. That does not seem correct and I see no little flat washer in the diagram. I have it installed with the "o" ring first, then the flat washer, then the spring, then the screw.

Anlard
Posts: 14
Joined: Thu Apr 14, 2022 8:10 pm
Location: Secane Pa Delaware County
What Virago you Own: '84 XV 700

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by Anlard » Tue Apr 26, 2022 5:11 pm

Actually, with a bit more reading on this site it looks like they are installed correctly. The spring on the screw, then the washer, then the "o" ring, then inserted in the carb.

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ViragoJoe
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What Virago you Own: 1996 Virago Special XV1100SH

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by ViragoJoe » Wed Apr 27, 2022 6:11 am

Anlard wrote:
Tue Apr 26, 2022 5:11 pm
Actually, with a bit more reading on this site it looks like they are installed correctly. The spring on the screw, then the washer, then the "o" ring, then inserted in the carb.
===================================================

Anlard,

You may want to post the link where you found that to help others.
ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)


NOTE TO ALL:
:arrow: Please edit your profile with location (State/Country) & Bike Information. It will aid us in assisting you!


All topics are archived by vehicle families for easy perusing and to find answers.

Also: If this website was helpful, please consider donating to help keep this site here for yourself and future Virago owners.

Anlard
Posts: 14
Joined: Thu Apr 14, 2022 8:10 pm
Location: Secane Pa Delaware County
What Virago you Own: '84 XV 700

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by Anlard » Wed Apr 27, 2022 8:32 pm

Joe, ....and all. The information on the pilot jet was obtained from THIS great website. This is the second time I found answers to questions I posted by navagating around here (check out the article about running rich/lean). My suggestion to anyone else is to look around this repository of great information to see if your question is actually already answered here.
Now, for an update on my xv700, it starts right up from cold now and seems to run fine. I set the pilot screws and all that is left is sync the carbs and I should be good to go. Just from setting the pilot screws it seems that the rear cylinder is pulling more than the front and, with the idle set to the minimum, still runs at about 1300 rpm. The sync should take care of that. Unless something else happens, this should be a done deal.

Anlard
Posts: 14
Joined: Thu Apr 14, 2022 8:10 pm
Location: Secane Pa Delaware County
What Virago you Own: '84 XV 700

Re: 84 XV700 Running Rich? (Secane Pa Delaware County)

Post by Anlard » Wed Apr 27, 2022 8:43 pm

One last thing, ..to take a gander at that Hitachi Carb article, you can Google "xv700 pilot screw adjustment" and you will get a link to "Virago Hitachi Carburetors - ViragoHelp.com". It will take you there. Enjoy.

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