I finally started tearing into the siezed GS500 race bike engine, to identify the cause of the failure and determine the best course of action for repair. Was kind of hoping it was something simple...
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB100248.jpg)
Guess not.
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB100249.jpg)
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB100251.jpg)
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB100250.jpg)
Other cylinder looks a little carbed up, but otherwise fine.
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB100252.jpg)
I'm not sure at this point if a piston failure lead to the bottom end failure, or whether the rod or rod bearing went out, causing the pin to be torn out of the piston. Would appreciate experienced input on that.
Quote from: burning1 on November 11, 2011, 02:13:56 PM
I'm not sure at this point if a piston failure lead to the bottom end failure, or whether the rod or rod bearing went out, causing the pin to be torn out of the piston. Would appreciate experienced input on that.
It broke. Don't try to start it up without oil :thumb:
:icon_mrgreen:
I'm not a mechanic's son. And I can forward the pics on to my maestro mechanic for his Opinion if you like. But I would be inclined to think the rod or rod bearing went out before the piston. Rods, bearing, shafts, etc., I think, would all go first, which can then lead to other things. Though, in the scheme of things, whether the rod or bearing went before the piston the result is the same.
I've put the pics to him so we'll see what he says just by the pics.
Michael
In this case, knowing exactly what failed could be helpful... I have a couple of other engines that I'm planning on building up to race on, so if I could identify this as a piston or rod failure, it may be worth investing some money in aftermarket parts to help prevent this kind of failure from happening again in the future.
How many k's were on the bike before you turned it into a race bike? And how long was it a race bike before it failed? Yeah looks like you did a good job doing it.
4K miles on the bike before it got raced.
25 days or so. So, probably 3K miles of race use. High oil consumption rate on the race bike. Oil was allowed to get about a quart below minimum about 5 trackdays before the failure occurred. Noticed a slight ringing from the engine after that, but the sound wasn't exactly right for a bearing failure.
Engine seized suddenly. There was no momentary drop in performance before hand, or other indication that it was about to go.
holy smoke! .. Can i vote for this as seizure of the month .. Thats a hectic breakage!
I don't race, but I was recently made aware that my gs consumes a lot of oil as well, when riding down the road I lost a ton of power and started hearing what I would call a ringing sound as well. Upon inspection I was a full two quarts low. Could my problem be related? Am I heading for a siezed engine?
Quote from: Steel on November 11, 2011, 03:33:34 PMCould my problem be related? Am I heading for a siezed engine?
Signs point to yes. 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.
Huge number of lessons here, and I feel like a real fool for a number of the decisions I made.
looks like oil got low, piston got hot, turned plastic, then wrist pin pulled through = cablooie.it's gonna be hell to flush all the mess out of that engine and transmission.
Quote from: Steel on November 11, 2011, 03:33:34 PM
I don't race, but I was recently made aware that my gs consumes a lot of oil as well, when riding down the road I lost a ton of power and started hearing what I would call a ringing sound as well. Upon inspection I was a full two quarts low. Could my problem be related? Am I heading for a siezed engine?
the high oil consumption likely means rings. while that isn't a bad thing other than the expense and wastefullness, it could lead to a similar chain of events if/when the oil level is low enough to starve the pump.
mine would use 1/10th to 1/5th quart per ride depending on how much was high speed. normal in town riding meant little to no loss. i don't know if it has to do with the number of engine cycles or what, but the high speed stuff will definietly suck down the oil.
you could stop now, and ring your bike. i'd bet your oil consumption drops to very little. before you do that, do a compression check. and/or a leak down if the compression check shows one cylinder is crazy low. should be able to pinpoint if it's rings or intake/exhaust at least that way.
O0
Quote from: burning1 on November 11, 2011, 03:45:20 PM
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.
I may do that. Can you recommend a send away lab you've used before? Thanks for the advice!
I've read a lot of people use Blackstone Labs
http://www.blackstone-labs.com/
I don't know what caused the failure, but I'm looking at the pics of the cyilnder walls... they are awfully shiny. Not much honing left... I can't imagine you were getting a great seal with the walls looking like that. Less than 10K miles? Yeesh.
How do the cylinder heads (combustion chamber) look? Any clues?
Quote from: burning1 on November 11, 2011, 03:09:07 PM
...
Engine seized suddenly. There was no momentary drop in performance before hand, or other indication that it was about to go.
owch.
So, from a rider's perspective, what's the best thing to do when you're ON the beast, and the engine seizes up like that?
Quote from: Phil B on November 11, 2011, 07:55:13 PM
Quote from: burning1 on November 11, 2011, 03:09:07 PM
...
Engine seized suddenly. There was no momentary drop in performance before hand, or other indication that it was about to go.
owch.
So, from a rider's perspective, what's the best thing to do when you're ON the beast, and the engine seizes up like that?
do you guys mean sieze as in "the darn thing blew up, smoke everywhere" or the engine and wheel locking up?
That's what happens when your top end and your bottom end meet.
Looks like maybe the top of the piston decided to stay at the top of the cylinder, while the rod and wrist pin finished it's trip to the bottom? :dunno_black:
Either way you've done a good number.
The pot looks to have been overcome by friction and seized at TDC, probably when for that fraction of a millisecond it stopped carrying kinetic energy and become stationary prior to changing its direction of travel from up to down.
Inertia has then played its part and the mass and speed of the still moving parts including the whole bike itself have acted to keep the crank rotating. Upshot bring the now seized piston has been subject to a severe tensile load and it has failed at the weakest point, in this case directly across the little end journal where the pot contains the minimum amount of metal.......... For want of a better description the piston has been stretched and pulled apart along its axis. Secondary damage has then occurred to the cylinder and lower end as a result of loose pieces of the now broken piston
This has happened at high speed, had inertia been less at the instant the piston seized damage would have been less severe.
The question is why did the piston seize. The obvious answers being oil breakdown/starvation and/or overheating.
Quote from: Phil B on November 11, 2011, 07:55:13 PM
owch.
So, from a rider's perspective, what's the best thing to do when you're ON the beast, and the engine seizes up like that?
Pull in the clutch at the first sign that there's something seriously wrong for the engine, raise your hand up, and pull over to the side of the track. Most of the time, when the engine seizes it doesn't take out the transmission, so by pulling in the clutch you can maintain control of the bike until you can get somewhere safe.
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. I'm glad that I came out of it better than the bike did.
Quote from: rayshon on November 11, 2011, 08:00:14 PM
do you guys mean sieze as in "the darn thing blew up, smoke everywhere" or the engine and wheel locking up?
We mean seize as in, the engine suddenly stopped spinning, and the wheel locked up as a result. Engine wouldn't budge with a wrench on the signal rotor. No other obvious external signs of problems, and I had no idea how bad it was till I pulled it apart.
Quote from: sledge on November 11, 2011, 11:33:43 PM
The pot looks to have been overcome by friction and seized at TDC, probably when for that fraction of a millisecond it stopped carrying kinetic energy and become stationary prior to changing its direction of travel from up to down.
Piston wasn't at TDC when I pulled it apart. I will knock on it with the handle end of my wooden mallet to see how hard it's wedged in there. With that said, there's not much of a skirt to keep the thing square in the bore, so there's a good chance that it'll be stuck anyway, proving... Not much.
My learnings and experience tells me that if a pot starts to pick up or siezes due to oil starvation or reduced clearances it is almost always at either the top or the bottom of its stroke. This I believe is due to the fact it lacks inertia at these points and consequently is far more likely to be overcome by the increased friction it sees at these points due to the lack of lubrication. Mechanical failure is another issue altogether, its outcome is random and more difficult to diagnose.
Could it have seized or started to pick up at TDC or very close to it then been dragged down the cylinder a short distance before it gave way? Is there any damage or marks to the cylinder wall in the area above the position where the pot came to rest?
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
Quote from: burning1 on November 11, 2011, 03:45:20 PM
Quote from: Steel on November 11, 2011, 03:33:34 PMCould 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 ?
Quote from: ohgood on November 12, 2011, 05:51:15 AM
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?
Quote from: Steel on November 12, 2011, 06:39:12 AM
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.
Quote from: Steel on November 12, 2011, 06:39:12 AM
Quote from: ohgood on November 12, 2011, 05:51:15 AM
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. O0
Quote from: mister on November 12, 2011, 04:33:17 AM
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?
Quote from: Phil B on November 12, 2011, 07:40:45 AM
Quote from: mister on November 12, 2011, 04:33:17 AM
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
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 ..
Quote from: twinrat on November 12, 2011, 03:03:38 PM
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
I think we have found a new way to turn you boxer or briefs a new shade of brown.
Quote from: aussiegs on November 12, 2011, 04:20:57 PM
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"
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.
Quote from: aussiegs on November 12, 2011, 04:28:59 PM
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"?
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.
Quote from: aussiegs on November 12, 2011, 04:46:30 PM
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.
That too lol. But if your a die hard fan like burning 1 you might want to rebuild it.
Quote from: twinrat on November 12, 2011, 03:03:38 PMyou 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.
Quote from: ohgood on November 12, 2011, 06:55:40 AM
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. O0
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.
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!
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 :woohoo: 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.
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 (http://www.youtube.com/watch?v=W0iTLrI9G7k)
Wait, did he blow half the block off..?
REALLY should have gone back and torqued those bolts..... :mad:
In my case it was two quarts in 2300 miles, half street half freeway. I have my full instruments and I never saw an oil light. Basic reason would tell me that a third of the oil can't do the same amount of cooling, but if my light never went on can that mean there was no starvation at the pump? I'm searching for a silver lining here. In a couple of days I'll know if I can return to normal performance or not. I don't know if I'm ready to handle a seize on the road, as a rider, working clutch or no.
UPDATE: I've got my cams out just now to pull shims whose buckets wouldn't rotate, and while pulling the buckets for inspection I could plainly see what looked like glitter in the motor oil. This couldn't be normal, could it? All I could find on the forums was a thread about the first 600 miles, and how it's normal then. I'm getting the impression that something in my engine is/was under a lot of stress.
The reason I recommended UOA is that it would confirm whether or not your engine was seriously damage without a full tear-down. Getting the engine apart isn't terribly difficult, but putting it back together can be a bit of a pain. But if you're seeing a lot of metal in the oil, it's pretty strong indication that something is severely damaged in there.
If you pull it apart now, you may be able to repair it for a moderate cost. Bearings are $5-$10 per half, and a new rod is $50-$70 (may or may not be needed.) This is assuming that your crank is still okay.
Replacing the rod bearings means removing the cams from the engine so that you can get the cam chain off the crank, removing the side covers, and separating the cases. I'm not 100% sure on whether or not the clutch basket needs to come off or not at this point.
Regardless of whether or not you manage to repair the engine, you'll learn something from the process.
After pulling the other followers I did NOT see the same metal flakes present. Maybe the flakes where from fussing at that valve with the shim tool before deciding to pull the cams? I did however see that my two exhaust valves that had zero clearance had buckets that looked like they were wearing and starting to show a brassy color on the outside. The wear appeared even. When I tried to put them back in their places neither would go, I tried encouraging them gently with a rubber mallet, and rotating them with pliers and applying down force. I then tried each intake bucket and they went in easily, came out the same. So I have warped buckets (?) and I can replace them with new ones I suppose.
Does this indicate anything about the condition of my exhaust valves, springs, or other cylinder head components?
PS: Am I "threadjacking"? I'd be happy to start my own thread if so. I felt my issues were related, if not the same to the OP's, but I can also feel the focus moving a bit.
Quote from: burning1 on November 13, 2011, 05:14:09 PM
The reason I recommended UOA is that it would confirm whether or not your engine was seriously damage without a full tear-down. Getting the engine apart isn't terribly difficult, but putting it back together can be a bit of a pain. But if you're seeing a lot of metal in the oil, it's pretty strong indication that something is severely damaged in there.
If you pull it apart now, you may be able to repair it for a moderate cost. Bearings are $5-$10 per half, and a new rod is $50-$70 (may or may not be needed.) This is assuming that your crank is still okay.
Replacing the rod bearings means removing the cams from the engine so that you can get the cam chain off the crank, removing the side covers, and separating the cases. I'm not 100% sure on whether or not the clutch basket needs to come off or not at this point.
Regardless of whether or not you manage to repair the engine, you'll learn something from the process.
tl;dnr: I'm a poor kid and I don't like rocking the boat.
Some backstory, and narrative about me: I'm willing to tear down and look, but I want to be as sure as I can be that it's necessary, for my first time especially. My gs is intended to be my daily driver, it's currently my only form of transportation. I have to be frugal with my resources and my downtime, as much as possible. I haven't messed anything up yet being noob, knock on wood, but it would be particularly shitty for me to be meddling and exposing myself to extra expense by f%$king up.
I very appreciate your advice. It's not my intention to be rude when it looks like I'm second guessing you, it's my way of adding details and trying to be sure I was clear, so that your advice still applies.
Quote from: burning1 on November 12, 2011, 12:16:42 AM
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.
I'm glad that I came out of it better than the bike did.
It was a catastrophic failure of a relatively stock engine. Yes? :dunno_black:
The important issue is your safety and survivability when pushing a low-tech mill that hard. (I'm assuming the internals were stock?)
Either way, glad you're OK burn1.
Please take the time to heal-up properly before pushing the envelope again.
Take care,
-Ej-
More detail:
Bad rod, removed from engine:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130276.jpg)
Shame that it came out a little blurry, but the best overview picture for how the rod and crank looked when split:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130256.jpg)
Detail of the rod and balancer shaft:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130257.jpg)
Detail of balancer shaft damage:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130259.jpg)
Detail of damaged rod journal:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130272.jpg)
Detail of good rod journal and crank bearing:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130266.jpg)
Detail of crank bearings:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130279.jpg)
Detail of 'good' rod bearings:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130282.jpg)
A couple of details to add...
First, the failed piston was about 27mm from top of stroke where I found it; about halfway between TDC and BDC. Crank was rotated near BDC when I found it, so it did appear to spin a little after the piston shattered.
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB130264.jpg)
Damaged piston moved freely in the bore when I checked. It could be pushed up and down the bore by hand.
Oil pickup system in the GS seems pretty decent. I can't imagine it sucking in air unless there was less than a quart of oil in the sump. Uncovering the pickup through acceleration or braking would require huge forces, esp since there is a splash guard between the pan and the crank... I'm doubtful that the engine was without oil, though it could have been lacking splash lubrication, low oil pressure, or high oil temperature.
Inspecting the rods, it appears that the big end of the rod is lubricated by the crank, and has a jet designed to spray oil onto the cylinder walls. The small end of the rod and piston skirt appear to be splash lubricated, partially by this jet.
Most of the bearings appear to be in okay condition. I noticed some signs of wear on the crank bearings, but nothing terrible. The non-bent rod had some obvious scouring on the bearing surface, though not the worst I've seen in pictures. Crank bearings seem to be in comparatively good shape.
Looks like this is probably a bottom end failure that resulted in a piston failure. I think we'd have had a much better idea of what went wrong if I had tore the engine down before the whole thing went to hell.
So we're down to more oil being needed and cooled?
Not that I'm a mechanic but. . .
This is a low mileage engine that's properly maintained and is operated in its factory specified RPM range?
I don't get it? (http://smileys.on-my-web.com/repository/Thinking/thinking-018.gif)
Those photos are frightening.
Ej, this is an engine that was run under race conditions with low oil and - one which was a high oil user and which had not been top up in the last few races after damage had been done previously. You cannot cause damage and then subject the bike to similar conditions which caused the damage and expect nothing to go wrong.
Michael
Pretty much what Mister said, although a similar failure is very much possible on a street bike if you let it get low on oil and ignore the indications that something has gone wrong.
For what it's worth, I'm not entirely convinced that this was caused purely by a low oil condition. Everything else in the engine looks very very good. If it is oil maintenance related, it may also be in combination with a oiling weakness in the engine. I'm going to take some detailed photos of the failed rods and see if I can dig out some bits of the bearing to see if there are obvious signs of over-heating and wear associated with lubrication failure.
Read my reply #27 again i do not believe you had a big end failure it is not discoloured enough .you had a piston skirt failure for sure . look at your piston where you can see all the oil hole drillings exposed and this never happens unless a piston skirt has failed at this point .seen this before ...check with a magnifying glass and you will not find a single bruise there ,only a crystaline surface that is oil inpregnated . this is from the crack developing over time ,its just badluck..
I've seen a lot of good theories on what happened. Wish I had torn the engine down before it failed... I think the answers would have been a lot more conclusive.
New photos for everyone...
Detail of big end bearings from broken rod:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140284.jpg)
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140286.jpg)
Detail of broken rod, showing signs of heat discoloration:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140297.jpg)
Detail of broken rod, showing wear to the big end and detail of breakage:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140299.jpg)
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140301.jpg)
Little end of broken rod, showing heat discoloration of pin:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140304.jpg)
Detail of broken piston & bore showing clean bore, wear on pin bore:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140365.jpg)
Detail of surviving rod, showing bearing wear:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140328.jpg)
Detail of surviving rod, showing discoloration of little end:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140337.jpg)
Detail of surviving piston, showing discoloration of pin:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140339.jpg)
Detail of surviving piston, showing pin bore wear:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140359.jpg)
Detail of surviving piston, showing skirt condition:
(http://i261.photobucket.com/albums/ii63/ctbarbour/PB140340.jpg)
Putting up all those photos & captions is a lot of work.
Thanks for taking the time to post it all.
BTW: I ride like an old hen. I couldn't imagine pushing an engine to that point. Low oil or not.
Thanks for explaining all this stuff too. :cheers:
-Ej-
Wow you can see the bronze coming through in those bearings.
Your piston does not show excess heat after all the hours that have been put on it since new,though your piston pin does show over heating .and colouring ,you need to have your pin apush fit by hand when cold and able to be pushed through piston and small end eye at same time.A piston in good running condition normaly
has a black carbon burn mark underneath that is with non detergent type oils from my experance..
Hi burning 1,, this is a book that should grace you book shelf .TUNING for SPEED BY PHIL IRVING First copy written 1948 but since updated . this is extremly valuable knowledge if you are racing these older design of air cooled motors and can be applied to water cooled to.
Quote from: twinrat on November 16, 2011, 11:53:00 PM
Hi burning 1,, this is a book that should grace you book shelf .TUNING for SPEED BY PHIL IRVING First copy written 1948 but since updated . this is extremly valuable knowledge if you are racing these older design of air cooled motors and can be applied to water cooled to.
Thanks so much for the book reference. I was hoping to find a good book on building air cooled motors, but I didn't know where to look.