Damned Virago!

I am working on a neighbor's 1985 Virago 1000 which would not run. I had it running pretty well last week (last ran on Monday). The bike had been worked on last year, with carbs taken out and cleaned by a previous owner (before my neighbor). My neighbor could never get the bike to run, I got it to run after tightening all air box and manifold connections.

Went to start the Virago after a week and she will not start. After re-adjusting the air screws, I got it to run for a while and then it stalled and would not restart. I Took the air screw all the way in and out 1 turn (estimating as the carbs are in the bike and it is difficult to get a screwdriver in there) and nothing. I take them out about another half turn and I get backfires. I get either backfires or not a sputter. I am getting fuel as the bowls are full and I am getting spark. DK what the hell is going on.

I now have the idle screws out about two turns (out is supposed to be rich on these carbs). I can crank and crank and get nothing, but the front cylinder will pop when I stop cranking. It feels like it is lean. Bowls are full. The only difference between today and last Monday (when it ran fine) is that the air temp is about 20 degrees colder. I did have it running a bit earlier today, but it just died on me.

I would be very suspect the carbs are not as clean as you may think, Also be sure to check the fuel petcock as a vacuum opp petcock can cause inconsistant tuning problems when they're on the way out

Timing?

In reply to Blitzed306:

I am thinking fuel delivery as well. I also think the carbs are jetted too lean to run when it gets much below 50 degrees. Last Monday, I had it running pretty well when the air temp was about 50. Yesterday, when it was about 40 or so, it ran a bit. By the time the air temp was around 35, it was no go, even with full choke and the idle screws very rich.

Yeah, a lot of guys just spray off whatever's visible inside the bowl and call it a carb cleaning. I'd go back through them very thoroughly, poking out every passage and making sure air blows through all of them. It doesn't take more than a nearly-microscopic speck of crud to block up a passage enough to keep it from running.

And tell your neighbor to start researching starter clutch repairs, and to bank enough for the parts. It's pretty much just a matter of time before it craps out.

Oh, the starter is acting up. When I had it running it was kind of fund to ride (for a cruiser), but I hate working on this bike.

Did you try starting fluid? If you can get it to run, and keep,it running on starting fluid, you can rule out timing and spark issues. Also see if you can rig a remote tank, there may be rust in the tank or old gas. Also check to see if there is a screen in the petcock that may be clogged.

Welcome to todays gas and small engine carbs....

On the note of cleaning carbs, BOILING them in lemon juice is the way to go. I know it sounds crazy, but it is the best method I have ever tried and it is environmentally friendly

Moparman Dork... Your dealing with a 28 year old bike so start with the simple and move from there.

First, check the carb to manifold boots (rubber) for cracks and air leaks that will make it run lean at almost any setting. Spray some heavy fluid that will act as a temporary sealant like very soapy water or very light oil. I'm assuming there's fresh gas in the tank that's not loaded with water. If in doubt let some drain from the fuel bowl into a jar and let it settle for a few moments. The water, if there, will separate out.

Second, as others mentioned, your assuming that previous owners carb rebuild was a true rebuild. The most critical part of the carb in your situation are the low speed jets which can become fairly easily clogged by long periods of disuse between infrequent runs. This allows the gas to evaporate from the fuel bowl causing the low speed (idle jets) to become clogged with evaporated residue. If that's your problem, and I'm betting it is, then no matter what else you try it won't work.

Third, you might also check the electrical connections at the coil as I've had Viragos before that exhibited strange poor running and unexplained stoppages because of unnoticed corrosion on this connections.

In reply to Moparman: Virago starters are notorious for going bad as a result of their type. They use a one way clutch set-up that depends up the engaging arm to be able to gain traction on the starter ring gear (over simplified. They aren't that difficult to rebuild but can get expensive if left to go really bad.

Temporary fix would be to try leaning the bike slightly to the LEFT as you engage the starter in an effort to help the starter clutch to starter ring engage.

Pull the carbs, disassemble one at time, and dip them, either in the lemon juice mentioned earlier (I have to try this some time) or in proper carb dip from an auto parts store, I like the NAPA stuff. Blow them out with compressed air. Be careful cleaning with mechanical means, you dont want to enlarge any of the passages in the carb.

Unless you put the gas into a clean and empty tank, drain the gas and fill with fresh premium, ideally Marine premium as it doesnt have ethanol typically. You would be surprised how tough it is to start a bike with old gas even if it smells and looks OK.

Charge the battery and hook a booster pack up. My experience with bikes is if the batteries get even a little flat, they wont start even though they seem to be cranking OK if just a little slow.

Pull all the plugs and burn them off with a torch to make sure they are completely dry, then while you wait for the plugs to cool down, spin the motor over a bit without the plugs to empty out the cylinders.

Reset the the carbs to the factory spec, make sure the boots are in good shape, the airbox is installed, OEM air filter is installed, and give it a go. It should start.

Seems to me that old bikes are not very tolerant of anything being even slightly out of spec. Only way to make sure its right is to go through it yourself from start to finish.

I just got done rebuilding the carbs on a CBR600F3. No wonder it didnt run, they were given a hose down with carb cleaner only and one of the main jets was loose and sitting in the bottom of the bowl. PO said it ran OK for a while, was hard to start, and then dropped a cylinder. After some time and effort, it starts in a few seconds in below freezing weather just by looking at the key wrong.

Beware low voltage. If the battery is reading 12 volts or below, the ignitors are notorious for not working correctly. Usually only one cylinder will fail, and at that it will fail by firing along with the other cylinder. So you'll see spark, but the engine won't fire. Only detectable by using two timing lights at the same time.

But I'd also be highly suspicious of the condition of the carburetors. They are not easy to clean, and generally aren't well cleaned.