Well THERE'S your problem!

[mister]

At first glance of the photos my mechanic said "Without a closer inspection or knowing the circumstances leading to this I would have to say bearing failure, followed by overheat... it can also be due to fault in materials. Whats the condition of the rods?"

After you revealed the bit about the noise after being a tad low on oil he mentioned, "Bearings don't necessarily make bad noises before they let go... if they let go the whole bottom overheats and start the melting effect. Really a GS 500 intended for track use should undergo some modifications including pistons etc "

Michael

[ohgood]

Could my problem be related? Am I heading for a siezed engine?

If I were you, the first thing I'd do is pull an oil sample out of the engine, and send it in for used oil analysis. They can tell you what's in the oil, which would give a good indication of whether or not you experienced some sort of severe engine malfunction. I was planning to do this myself, but the engine went before I took a sample.

oil analysis in an early game tells you how much, if any, the metal parts are wearing against each other, or the viscosity of the oil. oil analysis... at this point why ? for that matter, oil analysis, at any point - why ? the test can tell you that something is touching something else, or did once, more than it should, but will not prevent a teardown for the real diagnosis.

pulling the head and cylinders and actually looking at the condition of the rings/pistons/bores gives a very good condition of the top end. if either the top or bottom end was to start spreading shards of aluminum, steel, and hardended bits of bearings around the engine, I personally would write the whole thing off and get another one. toast is toast.

thoughts  ?

[Steel]

I personally would write the whole thing off and get another one. toast is toast.

thoughts  ?

I'm certainly interested in hearing thoughts here too. I'm very much a freshman in mechanics. If I did need to do a total engine teardown, I can't help but think about how much I'd learn. I probably wont see on my own the relative cost/benefits involved however, so I welcome the advice of my betters on these scenarios.

That being said, nothing has blown up yet with my bike, OP is the one with the tragedy. I'm still waiting for my valve shim tool to arrive in the mail so i can correct my exhaust valves that have no clearance, zero clearance where the bucket doesn't spin freely. Please hold the angry stares and eye rolls, I bought it that way and I'm playing catch up. I believe I need to correct some other basic maintenance issues to try to establish a baseline performance before I should consider major mechanical work, right?

[noiseguy]

I'm certainly interested in hearing thoughts here too. I'm very much a freshman in mechanics. If I did need to do a total engine teardown, I can't help but think about how much I'd learn. I probably wont see on my own the relative cost/benefits involved however, so I welcome the advice of my betters on these scenarios.

Get/find a dead engine to tear apart... something free. Practice getting the bolts out without breaking them, see how things go together, etc. You'll learn a lot. I did this when younger on stuff I never intended to reassemble. MC engines esp don't get rebuilt as often... anything major goes on them, folks just swap in a used unit.

[ohgood]

I personally would write the whole thing off and get another one. toast is toast.

thoughts  ?

I'm certainly interested in hearing thoughts here too. I'm very much a freshman in mechanics. If I did need to do a total engine teardown, I can't help but think about how much I'd learn. I probably wont see on my own the relative cost/benefits involved however, so I welcome the advice of my betters on these scenarios.

That being said, nothing has blown up yet with my bike, OP is the one with the tragedy. I'm still waiting for my valve shim tool to arrive in the mail so i can correct my exhaust valves that have no clearance, zero clearance where the bucket doesn't spin freely. Please hold the angry stares and eye rolls, I bought it that way and I'm playing catch up. I believe I need to correct some other basic maintenance issues to try to establish a baseline performance before I should consider major mechanical work, right?

sorry, i wasn't suggesting for -you- to tear yours down just yet. a loose motor mount or fastener can make a squeak, that sounds remarkably like a bearing in failure mode.

the valves are something that either get done proper, or never. you've done nothing wrong here. it's not terribly difficult, just have to be methodical about the order and not ddropping things in the engine. you'll find either the shim tool slips in the first time, every time, or you fight it for hours before it finally works. i'm going to call it 'muscle memory' as in your muscles being trained how to manipulate the tool into position. you'll see what i mean.

i've met people that send off oil analysis for every oil change, on brand new japanese motorcycles. why ? beats the hell out of me. generally, jap bikes last 100,000 miles or more with just a little maintenance. it's been proven synthetic oil doesn't matter in this reguard, nor does parking it over a crystal pyramid and chanting nightly. the things are made to last and last. rev limiters do a fine job (on newer bikes) keeping things below a known bad area of piston speed an lubrication failure. with so much engineering build into the engine, i really don't see a reason to see what the metal content of the oil is. change it, regularly, and enjoy the ride. 

[Phil B]

After you revealed the bit about the noise after being a tad low on oil he mentioned, "Bearings don't necessarily make bad noises before they let go... if they let go the whole bottom overheats and start the melting effect. Really a GS 500 intended for track use should undergo some modifications including pistons etc "

Michael

Guh.... sounds a little extreme. Or down on "the little guy".

Aren't unmodded GS's used on track all the time?  Why's this guy recommending piston changes?
Is there really a good reason, or is he just dismissive of anything not shipped as an "R" model?

[mister]

After you revealed the bit about the noise after being a tad low on oil he mentioned, "Bearings don't necessarily make bad noises before they let go... if they let go the whole bottom overheats and start the melting effect. Really a GS 500 intended for track use should undergo some modifications including pistons etc "

Michael

Guh.... sounds a little extreme. Or down on "the little guy".

Aren't unmodded GS's used on track all the time?  Why's this guy recommending piston changes?
Is there really a good reason, or is he just dismissive of anything not shipped as an "R" model?

He's not a great fan of air cooled (and he has previously seen a blown GS due to continued highspeed riding). But he does like replacing things on his bikes. Like boring out his BMW F800 to a F900, a previous ER5 became an ER750, you get the idea. He likes to Enhance the bike. Each new bike he gets he will not ride it until he has done both front and rear suspension suited to his weight specifically. We rib him about things not being CF on his bike. Couple years back he bought a BMW SR1000RR. I think they sell for like $29k down here. He gets a few thou discount from BMW cause he's "in the trade". By the time he had finished removing bits and replacing them with Sturdier bits his total spent including bike was $63k! And when he was done he never rode it! BMW asked him if they could use it on their display at a bike show.

So, like he said, He would replace the bits likely to wear harshly with something sturdier Because it is being raced.

Michael

[twinrat]

i see in your 4th picture of the bottem of the piston what looks like a darker colour on the left side of the piston where the skirt has  let go and dropped down the bore and become jammed between the conrod and bottem of the bore lip .the force of rotation has smashed the pin out of the piston which was locked  in the bore because the conrod being forced that way by the jammed broken skirt .You will find no signs of piston seizure in the bore.But you will probably find a dent or bruise in the bore on the right side where it jammed ..
Causes of piston failure looking at photo  i would have to ask if all those oil holes are in standard pistons because it looks like it let go along those holes . could you post a photo ove the bottem of a standard piston and i could give you a hint on reducing the number of oil holes if it has been modified from standard ..
Looking at 4th photo again it snapped the right side piston skirt right off because it slapped the bore with sutch force  you will probably find thes peices in the bottem . you were lucky to stay on with a lockup like that ..

[mister]

you were lucky to stay on with a lockup like that ..

Burning didn't stay on. It happened mid corner. Bike went down. Here "In my case, it went in the middle of a corner with no warning, and put me on the ground before I knew what had happened. Bent the bike up and dislocated a shoulder in the process."

Michael

[slipperymongoose]

I think we have found a new way to turn you boxer or briefs a new shade of brown.

[adidasguy]

I think we have found a new way to turn you boxer or briefs a new shade of brown.

The double meaning of "skid marks"

[slipperymongoose]

But I agree with misters mechanic, there has to be a cause to this. Based in info from previous posts, lack of adequate lubrication and high load has probably caused bearing failure combined with the heat generated by the lack of lubrication. To prevent this in the future maybe go stronger rods and pistons but also increase the oil capacity so there is plenty of oil getting splashed about providing the essential cooling.

[Phil B]

But I agree with misters mechanic, there has to be a cause to this. Based in info from previous posts, lack of adequate lubrication and high load has probably caused bearing failure combined with the heat generated by the lack of lubrication. To prevent this in the future maybe go stronger rods and pistons but also increase the oil capacity so there is plenty of oil getting splashed about providing the essential cooling.

errr... how does stronger rods/etc help? Seems like the problem is "no oily, no slidy-slidy" inside the engine. Stronger rods would probably only make a bigger mess of the insides of the engine in that case.

Contrariwise, seems like what is needed, is "stop the oil going away" ?

Whats the best way to do that, for a stock->track conversion?
S
Replace stock, with "magical track spec" piston rings or something?
Or perhaps more simply, "switch to a better (full synthetic?) grade of oil"?

[slipperymongoose]

Because the engine is going to be used at wot for most of its life of course you ramp things up inside the engine, and you make sure that the oil gets everywhere it can with no starvation.

[ohgood]

Because the engine is going to be used at wot for most of its life of course you ramp things up inside the engine, and you make sure that the oil gets everywhere it can with no starvation.

or, instead of rampaging through catalogues for gs parts of higher quality and service, just upgrade to a r6 or similar already upgrade machine for track only use ? it's on the same price level as a street-worthy gs.

[slipperymongoose]

That too lol. But if your a die hard fan like burning 1 you might want to rebuild it.

[burning1]

you were lucky to stay on with a lockup like that ..

Did not stay on the bike, unfortunately. Went down in Turn 15 at T-Hill, dislocated my shoulder, ruptured the gas tank, bent the frame, broke off a clip on, put a few holes in my leathers. Bad crash all around.

i've met people that send off oil analysis for every oil change, on brand new japanese motorcycles. why ? beats the hell out of me. generally, jap bikes last 100,000 miles or more with just a little maintenance. it's been proven synthetic oil doesn't matter in this reguard, nor does parking it over a crystal pyramid and chanting nightly. the things are made to last and last. rev limiters do a fine job (on newer bikes) keeping things below a known bad area of piston speed an lubrication failure. with so much engineering build into the engine, i really don't see a reason to see what the metal content of the oil is. change it, regularly, and enjoy the ride. 

I do UOA every 6K miles on my German bike, attempting to put the synthetic vs conventional oil theory to the test. So far, my results show that synthetic produces significantly less engine wear (going by wear materials) but that a good conventional doesn't sheer as fast as some of the stuff I've read would suggest.

[the mole]

I'm inclined to agree with sledge's analysis. I've never seen that kind of piston damage caused by a bearing failure, looks like a piston seizure-piston broke(as I often am)-major carnage. the bearings might not even look too bad, although if the whole sequence was started by a lack of oil it all will be pretty messy!

[burning1]

Just staying on top of the oil will help. It burned a *lot* of oil; so much that I only changed it once in 30 days of use, and it still looked clean. Burned about .25-.50 quarts per trackday... That's a lot; 2-3 quarts per 1000 miles, but not so much that the bike would be dangerously low if checking every day in the morning. Problem was that I went 3 days without checking it. Of course, at the time I was doing 2 track-days a week, so it didn't take long to cause a problem.

A huge part of the problem is I ran it without the instrument cluster, and didn't bother to wire up a oil pressure light or gauge. Definitely something I would do in future track-days.

Oil pressure to the rods is something that may be possible to address through a few means... Modifications to the oil pump, oil pump gears are possible. Not sure, but it looks like there's an oil pressure regulator that might be tuneable. Could look into adding an oil cooler, which would help keep the oil temperature lower. Could possibly modify the bearings, crank, or rods for better lubrication.

When I disassemble the engine I will inspect the good rod to see what the condition is over there. If we see lots of these failures, I'd be curious if this is the piston that usually does so, suggesting some sort of a design flaw.

As I believe I mentioned above, lots of the bottom end parts have been updated on recent GS500F models. Off the top of my head, there are newer rods and pistons... Might also be a newer crank. Curious if the updated parts are designed to address this sort of thing.

Also... As far as I can tell, the oil ports are normal. This piston is stock, off of a 93. First time it's been open since the bike was in the factory, and the pistons look identical to other pistons I've seen.

[the mole]

For what you're doing to the poor thing, an oil cooler would be a good investment IMHO! As to the oil warning light, I'd be looking for a sender that cuts in at say half normal oil pressure, normally they are set to a fraction of that so they don't upset people when its idling. By the time the standard light cuts in due to low oil, the motor would be ready to put under your bacon and eggs.


And if you think you did a job on your motor, check this:
http://www.youtube.com/watch?v=W0iTLrI9G7k