Catastrophic engine failure (lubrication helps engines)

[donimo]

12mm I think.

 

[rcp]

Quick question, what size are the spark plug holes/threads?

Check your spark plugs against this NGK plug chart

If the plugs begin with B, then they're 14mm. My 1000s are 14mm, but I'm unfamiliar with the smaller GS engines.

Canadian Tire has one or two compression tester sets with the right adapters, but most of their models don't. Bring your plugs along to check. Any auto parts store should be able to provide you with one too.

- Richard

 

[duaneage]

I think you had a lean out condition caused either by the petcock or clogged screen. I see the petcock is new, did you replace the vacuum line to it? Is it tight?

Do you have a fuel filter? These are OK as long as they are small. Bigger filters cause vapor lock because there is no fuel pressure to overcome the natural gas buildup.

If you have good compression consider yourself lucky. Hot pistons are not a good idea.

 

[MrZig]

New petcock, no fuel filter, vacuum line is in good condition.

I took the plugs out and they aren't pitch white. They have some brown to them, so I think if it was lean enough to seize my engine they would be pretty melted.

 

[duaneage]

Not necessarily. As soon as it idled down the plugs would color back up. It's sounds (from your description) like lean out, the only way to know for sure would be to cut the engine when it occurred and pull a plug. Surface temperature is another indication, those portable infrared scanners are wonderful diag tools for this. If it is above 250 or 275 it's probably running lean. YMMV of course.

 

[MrZig]

Say it did run super lean. Why would it tick like it is? It couldn't be engine knock or detonation because it happend at low revs, under low throttle position, when it was first started up in the day so the engine was cold.

 

[SAN]

engine noise.

engine noise.

I know its stupid question, any Clutch or trans problems? SAN

 

[MrZig]

Clutch and tranny are fine. The only thing I noticed was that it was pretty clunky shifting into first gear but I imagine that applies to most bikes.

 

[MrZig]

Death tick and sucking power is often the Journal bearings.

(which the 650's do have) They are good bikes but not bulletproof roller bearing motors.

Coming back to this.. When you say journal bearings, which are you referring to? As far as I know, the main crankshaft bearings, the camshaft bearings and the con-rod bearings are all 'plain' journal bearings, right?

 

[Guest]

taliking about the crankshaft/main bearings. the camshaft is "plain bearings" too, but they're just machined into the aluminum don't normally fail, and don't cause the problems you're describing.

When it is on the bottom end, it saps power from your machine.

 

[MrZig]

taliking about the crankshaft/main bearings. the camshaft is "plain bearings" too, but they're just machined into the aluminum don't normally fail, and don't cause the problems you're describing.

When it is on the bottom end, it saps power from your machine.

Okay, that's what I figured. When it heats up and seizes, I'm guessing the bearing is welding itself to the turning bits and the engine loses power/seizes.

I spose the way to confirm this would be to take the base & head off and look for a change of color at the base of the connecting rods. This could cost way more than it would be worth to fix it, so I may end up just selling the bike for parts..


In fact, I know that the engine has been split before as the sealent coming out of the engine halves isn't stock. Perhaps the previous owner replaced the bearings without doing the other required work (polishing the crankshaft, making sure the clearance was right, etc) and I'm just getting the ****ty end of his stick.

 

[reddirtrider]

The tick could be related to an overheating condition. It thins the oil to the point that you will hear noises that you never heard before. A tick isn't something that I'd be concerned with at this point. If it was a loud persistant knock, that's another story.

So, when are you pulling the jugs?

 

[MrZig]

The tick could be related to an overheating condition. It thins the oil to the point that you will hear noises that you never heard before. A tick isn't something that I'd be concerned with at this point. If it was a loud persistant knock, that's another story.

So, when are you pulling the jugs?

I dont know, the tick seemed pretty serious. It was happening both when the bike was first started up in the day, and it got extremely bad right when I lost power.

It was mainly noticable under throttle load, however you could still hear it in neutral if you revved it just right.

I'll be pulling the engine apart completley when I get back from my trip in a month or so. We're going to be taking my friend's car instead of bikes.

I'll post a very detailed engine teardown thread when I get back, however.

 

[MrZig]

Btw don't think this is a slight overheating problem. I drained the little bit of oil out of my oil pan annnd...





..I think it's time to find a used engine when I get back. After I tear this one apart ofcourse.

 

[gearhead13]

looks like ground up aluminum (piston) pieces to me

 

[reddirtrider]

I think it was stated that the best case scenario would be scuffing of the pistons. It's obvious that that's not going to happen. I always try to remain optomistic during a tear down, even when they take as long as this one.

Too bad it turned out this way.

 

[TheCafeKid]

Yes, do what Mark says. Pull the stator cover and see if you can turn it with a wrench/socket.

NOT the stator cover, the ignition cover will work just fine, and you wont lose oil or have a gasket that MUST be replaced...

 

[rudy]

NOT the stator cover, the ignition cover will work just fine, and you wont lose oil or have a gasket that MUST be replaced...

Ha ha! My bad, was still thinking XS650 with it's dry stator. Your eyes for details are like a hawk Josh! Kudos!