At my wits' end.

[jtolbert]

I'm sure you folks are getting tired of my questions by now.

So, my '83 GS1100GL has had all kinds of stuff done to it: new clutch discs, new coils, new wires, new plugs, oil change, new carbs and a bunch of other non-engine-related work. So, the bike ran absolutely fabulous on the night I got the new carbs, but the next day wouldn't start. That's when I found out the clutch was stuck and the starter was toast. So, I fixed those two issues. Now, the bike runs, but every so often (once every few seconds at last, often more often) a hard "ping" or "tick" and the entire engine/bike shudders, acts like it wants to die but keeps running.

The carbs have been pulled apart (again!) and there's nothing causing problems there. I'm really out of ideas. Any suggestions?

[focus frenzy]

sticking valve?

is it a ping or a tick? that is important as they are two different sounds with different possibilities.

[jtolbert]

I think it's more of a tick with a puff here and there.

What could it be either way? I'm so annoyed at the thing right now. If I could find my compression tester I'd see if everything was kosher compression-wise, but I can't find it cause SOMEONE "put it away." Of course, it's not in any of the logical spots...

[jtolbert]

SOMEONE found the compression tester. I guess I'll do that tonight. Won't tell me much, but it's better than nothing.

[Dave8338]

Check the compression numbers...if they look good, I'd suspect an ignition issue, I've never had it happen on a bike, but it has happened on other modded toys in the past and one car that then let go at somewhere around 9,500 RPM's (sad night)

[jtolbert]

So, I have compression numbers now:

1) 145
2) 142
3) 137
4) 152

Are those decent? All are within 10% of the highest number, but the lowest one just barely.

What's next?

[Clone]

When does it make this noise exactly? What exactly does it sound like? How does the bike react exactly? Many things can cause a sound, a lot of sounds can be described the same, but exact descriptions will get you a lot more answers. Can you provide a video or sound file of the sound?

[jtolbert]

I could probably grab a recording of the bike running and see if the sound shows up. Knowing my luck, it wouldn't.

The noise occurs at any RPM, but it's drowned out at higher RPM. The bike feels like it's down on power compared to when it was running great a few weeks ago before I discovered the clutch and starter issues.

It really is hard to describe the sound accurately. There's a "puh" noise that happens more often and then something that sounds like a hard click...The click is what makes the whole engine shudder.

[nabrams]

When it was running great, did you really push the envelope? If so, your cam chain may have skipped a tooth or a valve may be out-of-whack now.
Taking off the valve cover to have a look around (valves, timing, etc.) is a relatively small investment of effort that might reveal the problem.

[jtolbert]

I never beat on it when it was running nice...I'm not very hard on my bikes. At this point I guess I'm going to start looking at ignition and the cam chain setup.

[Dave8338]

Your compression numbers look good, I'm still going with ignition, though yours is electronic, I'd be suspect of the coils to the plugs, sounds like that "ping" you're hearing may even be a plug wire arcing, coil pack arcing, or something of that nature. Grab a spray bottle of water and wait for the sun to go down...start the bike and hit the wires and as much of the coils as you can get to and see if there is a wayward spark jumping out to meet you. No...you won't get a shock. :-D

[jtolbert]

That would be a real drag, considering I just replaced the stock (cracked/loose/torn) wires and coils with Dyna green coils and wires. I suppose I can try it, though.

[Dave8338]

Look on the bright side...you may be able to rule that out with a simple free test. \\/

[tconroy]

Check your plugs to see if you are running way too rich somewhere.Raw fuel will pop in the exhaust and cause the bike to "choke".Check your air fuel mixture screw to see if one has not backed out or something.Also check your choke rail to see if something is sticking there.

[walt]

Check your plugs to see if you are running way too rich somewhere.Raw fuel will pop in the exhaust and cause the bike to "choke".Check your air fuel mixture screw to see if one has not backed out or something.Also check your choke rail to see if something is sticking there.

I agree. Glowing carbon buildup can cause the fresh mix to ignite early. The intake valve is still open giving the pop. The flame front hits the piston as it is still rising and causes the shutter.