Sudden stalls after servicing

[smokestack]

Just had the carbs rebuilt and petcock replaced on my 2006 GS. Was able to ride it around for a couple of hours before it stalled suddenly going about 20mph. The starter motor sounds fine but it won't restart. After letting it sit for about 15 minutes, it starts right up. Ride it for another hour and same thing, very sudden stall and it won't start back up. This time I let it sit for about an hour and it starts perfectly, but only runs for about 15 minutes before it stalls again.

It doesn't sputter or lose power leading up to the stall, it just dies very suddenly. It won't restart with the petcock in any position. I opened the gas cap each time and didn't hear any air rushing in. The kickstand doesn't seat firmly when it's up and thought maybe the switch was causing the stall, but I'm able to crank the motor immediately after and it doesn't start.

I only noticed after the third time that the cable leading into one of the spark plugs was resting on the engine but none of the wiring was exposed, just a little melted "dent" in the encasement. It was also idling pretty high for those first couple of hours, around 3-4k. It never did this before the servicing so I assume something may have been botched.

[Big Rich]

I'd still be looking at fuel starvation. Next time it stalls out, check your float level immediately using the clear tube method. Could be the carb vent hose kinked / clogged.

Edit: you don't have an aftermarket fuel filter, do you?

[smokestack]

I'll try that. I'm just remembering that they had left the petcock on reserve and I was riding like that for the first couple of hours before switching it to on, and the stalling must have happened within an hour afterward. I'll see if I get the stalling on reserve tomorrow.

I bought it used but I never noticed a fuel filter and never installed one. I assume it would be near the petcock?

How long would it normally take for the bowls to refill if they were empty? Seems like I'm getting good starts 10-15 minutes after stalling, but it could be sooner.

[lucas]

Coincidentally, another member is having similar issues to yours.  I'd give the same advice to you:

http://gstwins.com/gsboard/index.php?topic=70531.0

[Big Rich]

I thought I replied to this, but my phone doesn't agree with me.....

A fuel filter could be between the fuel tank and frame petcock, or the frame petcock and the carbs. And if your carbs are vacuum locked, it would be obvious if you check them with a clear tube.... unless air rushes in thru the drain and unlocks the vacuum? Just guessing here....

[smokestack]

So it seems to only be getting about 2 or 3 miles before stalling now (maybe 10-15 minutes through a residential area).

Running it on reserve doesn't make a difference.

I was able to drain several ounces out of each of the carb bowls. I didn't try emptying them, just stopped after a few cap fulls. I found what I think is the carb vent hose (coming off of the carburetor and through a small air box), no kinks and unobstructed. I didn't hear air rushing in when I unscrewed the drain, and still not starting after I do that.

I was able to get about 40 miles out of it before it started stalling like this.

[smokestack]

Might also be worth mentioning that the fuel lines running off the petcock were replaced and the air filter was replaced when it was serviced last week.

[lucas]

If you are trying to verify the amount of fuel in your float bowls is correct you can use a clear piece of tubing.  Attach one end to the drain nipple and hold the other end up above the float bowl.  Where the gas rises to in the tube is the height of the fuel in the bowl.

[smokestack]

Lucas, thank you. Before I saw your post I decided to check the oil for the first time since I got the bike back and it's not reading on the stick and I can't see any oil pooled at the bottom. Christ...

[Janx101]

Check the oil with the bike held level. .. ie not on sidestand!

[smokestack]

Yep, you spared me another stupid mistake

The last couple of stalls happened immediately after upshifting and engaging the gear. I was going about 15mph last time and tried dumping the clutch into second to try bump starting it and just skidded the rear tire. Is that normal?

I really appreciate all of the help on this thread... this bike has been a thorn in my side, and worse that I haven't had the space to work on it myself. Just out of the shop after a month waiting on parts and now this. Oy

Edit: I'll try the clear tube test today but the bowls definitely aren't empty after stalling, so if it is a fuel starvation issue, it seems to be happening somewhere downstream.

[lucas]

You could try bump starting in second.

I don't think there is anywhere further downstream than the bowls, from there the fuel feeds through the jets.

[Big Rich]

Smoke - try pulling spark plugs when it stalls. White & dry = fuel problem. Black & wet = spark problem.

[smokestack]

I put close to a quart of oil in it to top it off, sprayed some penetrating oil into the cylinders in case anything was gunked up, and replaced the spark plugs. The ones I pulled off had been in for a long time but both are sooty.

I think it's always run pretty lean. The motor oil and exhaust both smell like gasoline. I'm worried that it's overheating and damaged something else since it was running fine for about 40 miles before this problem started, and stalls more quickly each time I've ridden it. I've read the ignition coils could be likely.

Is there a simple way to adjust the mixture on the carbs without taking it apart?

Rich, I'll try pulling the plugs next time it stalls.

Edit: lean, not rich

[Big Rich]

Well, the good news is that if was running rich then there's less of a chance of overheating.

Ignition coils could be the problem..... but usually OEM coils last for decades before failing. Assuming nobody has abused them of course.

You have a weird set of symptoms Smoke.... usually a rich smelling exhaust / oil means there's too much unburnt fuel blowing out or washing down your cylinder walls. But stalling after riding for a little while can be caused from running lean. I'm wondering if your float height is set high / float needles are leaking, but you also have a vacuum lock in your carbs causing the stalling.

Wait for somebody else to chime in though - I've got a touch of the flu and not thinking 100%....

[smokestack]

Thanks Rich, hope you're feeling better.

I got it stalled again and immediately pulled the plugs and didn't see a spark. Waited a couple hours with the plug in and it still wouldn't start, and killed the battery after a 20 cranks or so, so the battery must have been pretty low. Got it on the battery tender and pulled one plug pulled and did see an orange spark (that means a weak spark?), and it started.

So.... certainly seems like an ignition problem now. I had just read in a few places the the coils are notorious for getting hot and malfunctioning on these bikes. If it is running lean and hot like it seems to be, I guess that could exacerbate the issue.

I'm guessing it definitely couldn't crank if it didn't have enough power to create a spark.

[Janx101]

A strong spark disappears before the crank power goes. ..I think?

[smokestack]

orly...

[lucas]

Yeah a bad coil would explain the bad exhaust smell

[smokestack]

Lucas, you mean that the gasoline smell in the exhaust may be caused by no spark/no ignition?

Charged the battery overnight and no difference. I'm feeling around where the coils should be after it stalls and they're cool to the touch. Maybe the battery's junk.