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ViragoTechForum.com » XV500 » xv500 wont stay running.... starving for fuel... (SOLVED)

#1: Question xv500 wont stay running.... starving for fuel... (SOLVED) Author: khilsee Post Posted: Fri Jul 03, 2009 1:13 am

I am very new here and I have a 1983 xv500k that I just inherited from a friend of mine. When I first got it the bike would fire up (after many backfires) and idle semi alright... (with choke all the way on) .. at first you can give it a little rev or two before the whole thing dies.... NOW... we have determined that the timing is right on and we are getting sufficent spark all the way through and rebuilt the tci box... also new plugs and battery .. and proper adjustments of the tappets... I have pulled both carbs off and I am cleaning them out and letting them soak right now... this will be the SECOND time I have done this and I am still getting the same results which is why I tore them down a second time... It did NOT come with an air filter which we did end up trying to substitute a piece of foam for resistance... there are no vac leaks and we have already by passed the fuel tank to see if it was an issue in the petcock... we also tried to bypass the fuel pump as well... all yielded the same results.... bike will fire and idle ... but with any throttle it dies... seems like it is starving for fuel right??? PLEASE HELP!!

#2:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: gregthomas Post Posted: Fri Jul 03, 2009 2:03 am

Thr filter's the key to your problem - open cell foam is just like no filter at all.
Either find an OE replacement or an aftermarket listing for this model
Without a filter with flow characteristics similar to OE the carburation will be well out and respond just as yours is

Greg T

#3:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: khilsee Post Posted: Fri Jul 03, 2009 1:17 pm

anybody know where to find an air filter??? i have looked all over.

#4:   Author: scootermcq Post Posted: Fri Jul 03, 2009 4:29 pm

http://www.bikebandit.com/search-products?q=22U-14450-00-00&ch=1&sc=9&br=yamaha

http://www.boats.net/parts/detail/Y-22U-14450-00-00.html

By the way, welcome to the forum....

#5:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: khilsee Post Posted: Fri Jul 03, 2009 6:49 pm

thank you so much for those links!!! i was unable to even locate the part number and you nailed it!!! you are awesome!!

#6:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: scootermcq Post Posted: Fri Jul 03, 2009 8:40 pm

You are welcome...

One other thing to check is the air vent tubes & filters to the carbs. If they are plugged or clogged, you can idle fine, but your main jet can not get fuel due to improper air balance around the diaphragms.

If you look at this picture you will see where it is labeled air vent tubes. Make sure you get air flow through them and the hoses attached to them.



500 carb.JPG
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500 carb.JPG



#7:   Author: scootermcq Post Posted: Fri Jul 03, 2009 8:41 pm

To find part #'s in the future, go here:

http://www.starmotorcycles.com/star/parts/home.aspx

#8:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: Mr-M Post Posted: Fri Jul 24, 2009 3:13 am

Have you checked your carbs maybe the diaphragms are shot. I opened mine up and there were little tears in all four!

That would explain a lack of fuel once the the throttle opens up because the needle would remain in place instead of moving to allow more fuel into the engine

You can check this with the tank off and the air box cover removed. Once running the carb pistons should be moving. If not then you've found the problem.

I have a similar problem in my 500 - but in my case i think its the fuel pump - I'm ordering up the unversal round mikuni rebuild set because its only $4 vs $85 from the dealer.

Hope that helps!

#9:   Author: grazingazer Post Posted: Fri Jul 24, 2009 8:24 am

@ khilsee: for educational purposes there are no tappets in a virago overhead cam engine

#10:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: grnrngr Post Posted: Mon Apr 26, 2010 12:25 am

Hey! I've kinda re-inherited this one from Khilsee (it was mine originally)...and bought another one (for $300) because the TCI box is still (to me anyway) somewhat suspect. He did a good job cleaning the carbs, the diaphragms are fine, but the little rubber plugs and the gaskets under the block are hard as rocks and could be leaking internally. The carbs in the "new" one are way worse, so new kits are on their way. I put them back together and put the unmolested TCI box on it. The original box had been opened by the PO although it didn't look like he had done anything to it other than clean the goo off the board. We found a fried resistor, replaced it, and it seems to work OK but I wonder if its failure has maybe done something to one of the ICs. Anyway, got it back together and it runs pretty good, idles nice but still some popping and dying at intersections that I'm hoping will straighten out with a carb synch, but if not, I'll put the other carbs on it after they get rebuilt and I'll do these ones again with new kits. It does get down the road tho..I put about 20 miles on it the other day. So...we're not "solved" yet but a lot closer... BurnOut I'll try to get some pics up soon....

#11:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: grnrngr Post Posted: Tue May 11, 2010 4:04 am

Hmmm..put the newly cleaned carbs back on Red (the newer one) and although it was halfassed running with gooey clogged carbs, wouldn't run at all with the clean ones. Went home. Decided to check the jets on Black (the original problem bike) to make sure I had them in the right carbs, they checked out, but I noticed the band at the bottom of the front catb was loose so I could have had a vacuum leak there, tightened it up now it won't start. Went back out to Red, rolled it out and onto the center stand, was checking for spark and noticed #1 spark seemed to be intermittent as I played with the plug in the cap, so I clipped off 1/4" from each wire, put it back together and started it. Runs great on the front cylinder. New plugs are next for that one. Rode it around the alleys at the storage unit, first time it's rolled under it's own power in 16 yrs. Gotta change the oil and put the front caliper back on before I take it out on the road. Black, I don't know. I know it's not the TCi, the unmolested one is on it, it ran fine the day I rode it home, except for some sputtering I thought would clear up when I found the loose carb band, Just read about adding a second ground strap, I'll do that to both ASAP, go thru the connections again, maybe get a new battery although this one seems to hold a charge as long as it doesn't get seriously abused...

#12:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: grnrngr Post Posted: Wed May 19, 2010 2:12 am

I'm callin it solved...just got back from 50 miles on the freeway and it seems to be dong OK. Still has some minor issues but it runs good. Part of the problem with diagnosing this one is an electrical issue with the key switch. Seems it doesn't always get a good connection even tho the lights come on and the motor cranks. Anyway, long story short, rebuilt the carbs and took all the electrical connections apart, cleaned and put them back together, and it runs!! Red one runs great now too, put 120 miles on it over the weekend. Thanks for all the input and ride safe!!

#13:  Re: xv500 wont stay running.... starving for fuel... HELP!! Author: grnrngr Post Posted: Thu May 20, 2010 2:27 pm

heh....seems I can't call it "solved" since I didn't start the thread. Mods? Don't know if Khilsee will be back unless he decides he wants the bike again....
both bikes are running good, Red starts almost instantly with no choke, Black takes a little choke and some warmup time but runs good once warmed up. Hoping a carb synch will help that.
ViragoTechForum.com » XV500 » xv500 wont stay running.... starving for fuel... (SOLVED)


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