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Bike quit on me on the drive home. Again.

2275 Views 44 Replies 9 Participants Last post by  oldguy, 
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Mine's a 2006 VLX, 38k miles on it. Great bike, but I'm curious about a problem we're having:

About a month ago I was driving home, and I knew I was running low on gas. The bike started sputtering, so I switched to reserve. A few moments later, it started sputtering again and shut down. I coasted and pulled into a lot and tried to get it to start again, nothing. Thinking I might've actually run out of gas, I had my wife bring my gas can; I put about a gallon in, but the bike wouldn't start. Crank, but no fire. Eventually spent the battery.

Had it towed to the shop, and the mechanic charged the battery up, and it fired right up, and couldn't tell anything was wrong. His guess was that I had inadvertently flooded it when trying to get it to restart.

I took it to and from work last week, everything was fine. Today, coming home, the bike started stuttering, like I was running out of gas. I knew I had gas, having filled up last week. Bike conked out again, and I rolled into a lot. Tried to restart, first time nothing, second time, it coughed, and third time it started back up, and I was able to drive home. Would've gone straight to the shop, but he's closed Monday.

I'm curious what you all think might be going on. Something some SeaFoam would cure? Something clogging the fuel strainer screen? Perhaps a faulty fuel valve?

Regards,
Brian
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KiwiRider said:
If the fuel system works out, the next I'd check is the pulse generator if your bike has a single one. I had the same symptoms on one cylinder of one of my 86's, an intermittent pulse generator.

Does your model have a rev counter, and does it keep operating normally when the bike cuts out? If it acts erratically, it's an ignition problem.
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Nothing other than the speedometer. It felt exactly like when I'm all but out of gas on the main and switch over to reserve.
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swifty2014 said:
When it dies loosen the drain screw on the lower part of the carb bowl and see if 1 or 2 ounces of fuel runs out. That will tell about the fuel supply.
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I did wonder about the carb, but if that were the culprit, wouldn't it run badly the whole time?
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swifty2014 said:
Do this test=

Put your meter across the battery and see if at rest it is at least 12.5 volts. May need a charge first.
Then watch it while you crank it for 5-10 seconds and it should be above 9.5 to 10 volts minimum.
Then while running see if it can stay up to 13.5 to 14.5 volts as you rev it above 3000 RPM.
That will tell the basic health of the battery and charging system.
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I've been away from keyboard for a bit; let me make sure I understand what you're saying.

I've got a sae pigtail connected to my battery. You're saying to connect the meter leads to the pigtail and make sure I've got 12.5v, then while the meter's hooked up, crank it and watch for 9.5-10v, then while revving, confirm I get ~14v out of it, right?
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vito said:
When you get to reserve, you are at the bottom of the tank and any particles and gunk down there start swirling around and going places you don't want them to go. Make sure you don't have anything in your fuel line / fuel filter first. After that, start digging a layer at a time, basics first.
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I appreciate that: I'm trying to understand the basics yet :) and making sure I know exactly what I'm supposed to be doing. I do have the shop manual and I've read about removing the tank; the manual implies cleaning the retainer screen ought to be done from time to time.
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swifty2014 said:
When it dies loosen the drain screw on the lower part of the carb bowl and see if 1 or 2 ounces of fuel runs out. That will tell about the fuel supply.
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Thanks for the tip: I'm assuming the fuel should be nice and clear, right? no gunk, particles or anything in it? I plan to do it this weekend.
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swifty2014 said:
If it is running now do that test on the pigtail for the battery voltage.

The check for the carb bowls is to see if there is fuel inside when it falters.
If not the fuel delivery system is a problem.
You should never see crappy fuel.
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Ah: so then I should check the carb bowl once it's stalled out? And if there's fuel in there, then I've got an electrical problem, but if there's no fuel in there, then I've got a fuel supply issue (eg clogged screen, etc). Am I following you?
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OK, everybody, check this out:
1. Checking the battery:
Off: 12.8 v
Starting: 11.5v
Running: 14v

2. Checking the stator:
Ohms
A-B 0.6
B-C 0.6
C-A 0.6
AC Volts at idle:
A-B 11.2
B-C 11.3
C-A 11.3
From what I read, AC Volts should increase when revving the engine but for each pair (AB, BC, CA), voltage dropped when revving: it dropped to about 8v and held there (I revved and held for about 15 sec)

So question 1: Does this mean my stator's bad? and Q2: Might this be the cause of the bike conking out on me?
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brismith said:
I've been away from keyboard for a bit; let me make sure I understand what you're saying.

I've got a sae pigtail connected to my battery. You're saying to connect the meter leads to the pigtail and make sure I've got 12.5v, then while the meter's hooked up, crank it and watch for 9.5-10v, then while revving, confirm I get ~14v out of it, right?
Click to expand...
Here's what I've found:
1. Checking the battery:
Off: 12.8 v
Starting: 11.5v
Running: 14v

2. Checking the stator:
Ohms
A-B 0.6
B-C 0.6
C-A 0.6
AC Volts at idle:
A-B 11.2
B-C 11.3
C-A 11.3
From what I read, AC Volts should increase when revving the engine but for each pair (AB, BC, CA), voltage dropped when revving: it dropped to about 8v and held there (I revved and held for about 15 sec).

(Now, did I do this test correctly? When testing AC Volts, I had the stator connector plugged back in: was that the right thing to do? IOW, when testing AV Volts, does the stator need to be unplugged?)

Does this mean that the stator (or other component) is failing? And could that explain the original problem: the bike conking out on me out of the blue?
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swifty2014 said:
The stater should be UNPLUGGED from the regulator.
It may be up to 20 VAC at idle and go up above 50 VAC when revved up higher.
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Got it. Thanks. I redid the test, and with it unplugged, the voltage across all three combinations increase with RPM. I took off the tank too, here's how the screen looks:
Wood Metal Gun accessory Office supplies Fashion accessory

As I siphoned the gas out of the tank, it all looked clear: iow, no gunk or other stuff.
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KiwiRider said:
When it quits, can you start it again? If you can, your charging system is probably OK unless it's leaking AC or over-voltage. IME with Shadows, when the charging system quits you can run your engine for a while off the battery, and when that is drained too much to run you're going to be out of power to crank. The ignition system doesn't use that much power at all.
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The first time it quit, I couldn't get it to restart; it would (weakly) crank, but wouldn't fire. I exhausted the battery trying. (That's when I had it towed.) The second time it quit it acted like it didn't want to restart but finally did. But both instances of it shutting down felt exactly alike.

When I was testing the stator, I noticed the coupler for the regulator (right next to the stator) looked gross; at first I thought it was corrosion, but it turned out to be a white grease. Which got me wondering, should I regrease the connectors I've unplugged? (ie, the regulator connector, and the stator connector?) Then another thing I've been wondering is whether if this is an intermittent electrical issue, what are the chances that "reseating" the connectors would fix it (I doubt my luck's that good).

I was happy (I guess) that the tank tube looked clean. I have to learn how to open the carb bowl and see what's inside.
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swifty2014 said:
Yes you want to isolate the fuel from ignition systems that way so you don't spend hours and $$$ and get nowhere.
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Thanks for the tip. I think I'm on to something:

1. I drained about an ounce into a shot glass; gas looked good.
2. When draining out the rest, at the very end the carb pooped out a little black blob.
3. I took off the bowl, and here's what I found:
Motor vehicle Material property Gas Security Metal

4. The "top side" of the carb looked clean; jets didn't seem to be clogged, diaphragm looked good; I cleaned the needle.
5. I've got a new bowl gasket on order, but I won't have a chance to get back into it for a few weeks.

It'll be a miracle if I can get it all put back together without missing anything (I did take copious notes, though.) Fingers crossed that this is the culprit.
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Well I think I made things worse. After putting everything back together, the bike won't fire. It'll crank, but no vroom. I knew that right after a carb cleaning it could take a little more cranking than normal to re-establish vacuum. I wore out the battery trying, so I'm charging it back up. When trying to restart it, I'm pressing the button for about 5-7 seconds, then letting it sit for 30 seconds or so.

I replaced the float bowl gasket (the old one was pretty stiff), the air filter and its gaskets.

I took notes while taking everything apart, and followed the notes backwards putting it all back together. Are there any rookie mistakes I might've made?

On the plus side, I didn't smell any gas :)
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I pulled my plugs: they've barely got a year and a thousand miles on them:
Product Auto part Font Fashion accessory Titanium
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Thanks (as always), swifty2014, you've taught me a bunch already. Here's the latest:

After I pulled the plugs, I put a teaspoon of fuel into each cylinder. It tried to fire but conked right out. Then I thought, "What would swifty do?" so I opened the carb drain, and nothing came out. Which got me thinking. I removed the tank and confirmed the fuel valve worked: at "On" and at "Res," fuel poured out. But what surprised me is the fuel line between the fuel valve and the "fuel auto valve" had very little fuel in it, and the line going from the fuel auto valve and the carb had basically nothing in it.

Axman88 suggested early on that that vacuum shutoff valve could be involved. The lines between it and the carb "seem" OK: they're not brittle. (I've got the three way "T" vacuum fitting, not the 4-way "cross."). Is there a way I can check that the valve is working like it should?
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The shop manual shows connecting a hand pump to the valve and seeing if fuel flows through it with vacuum applied.

I misspoke about the crankcase breather plug. That's all there and intact.

I'll get a hold of a pump and see what I find out.
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The shop manual shows connecting a hand pump to the valve and seeing if fuel flows through it with vacuum applied.

I misspoke about the crankcase breather plug. That's all there and intact.

I'll get a hold of a pump and see what I find out.
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axman88 said:
Figure out which lines contain fuel and which is vacuum. Connect the fuel lines together, (As I recall, they were different sized) and PLUG the vacuum line so the engine isn't sucking excess air. If the machine runs with the fuel cutoff safety valve bypassed, that suggests the valve was bad.

One might choose to leave their bike that way. A lot of us managed to survive decades of riding machines that didn't protect us from every possible danger. Reliability goes up as components are removed, or as I always say, "If it ain't there, it can't break!"

Note that if yours is a California equipped machine, it has even more stuff to break, about 9 additional hoses to leak, a pair of extra valves to fail, and a charcoal can to rust out.

A hand vacuum pump is a nice tool to have, for diagnosing vacuum issues and for sucking on things. You can save time bleeding your brakes, for example, or get a siphon started. Using that tool attached to the vacuum port, the pump should quickly draw a vacuum which should PERSIST and not leak down, When a few inches of vacuum are drawn, fuel should start flowing through the valve.
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I had no vacuum to speak of, so ordered a new cover set. Check out what the old one looked like:
Auto part Wood Circle Metal Fashion accessory

That can't be good, huh? I won't be able to reinstall it until the weekend, but really hopeful this is the issue!

I can't thank everyone enough for their continued and patient help.
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Alright. Check this out: New video by Brian Smith I can't believe it.

Here's the things I wound up doing:
1. Changed fuel auto valve cover set
2. Cleaned carb bowl, replaced its gasket.
3. Replaced air filter.

I'm going to finish wrestling the silly seat back on (that's always been a pain), then I'm going to go around the block a few times to make sure things are good.

I do have one question as I put everything back together: do I need to put any kind of grease or sealant on any of the electrical connectors? When I was checking the stator, I noticed the connector had what seemed like an old grease on its fitting.

Many thanks to everybody for your help getting the Shadow back on the road!

Regards,
Brian
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