TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: F-Red on January 10, 2015, 01:43:08 PM
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Words to follow! :miserable:
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/973428AB-0C15-4915-AFA9-CA888AF04019.jpg)
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/AEDCB0BE-F06C-4746-827C-E278503DD977.jpg)
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/DD80FBEE-2EDF-4520-A6A1-607F8B004C69.jpg)
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(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/1C788A74-28EF-4BA3-A01E-DB04FA7BDC8E.jpg)
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Whoa.. let's hear the story behind this one F-Red!
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Damn!
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Did you forget to put the c-clips in?:jk: You might have some excessive clearance on that bore now. Is that one of those short 4 stroke pistons? Looks like your missing the needle bearings on the wrist pin bearing. I have 3 of those to order on my new wish list.
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Oh my...
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Wow. Ouch. I have never seen a rod break like that on a single cylinder 2 stroke.
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Little muriatic acid on that cylinder and it will clean right up.
:lies:
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Looks like a 4 stroke piston. I have seen worst...but not much worse. Hopefully it won't set up back too much or too long. goos luck
best regards
-Jason
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now thats what I call grenading a motor. damn
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rub a lil jb weld on her, she should be good as new ;)
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time for a lil forensic engineering.
John
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I have seen a lot of engines that looked similar to this when they are mechanically over-reved. There use to be a local track that had a wide open 4th gear jump that had a 180 2nd gear turn about 50 feet after you landed off of the jump. Some riders would down shift into 2nd gear while they were in the air and land with the clutch out. 250s turning 8000 RPM or more when they left the jump in 4th gear would be revved to around 12, 000 RPM or more when the rear tire touched the ground. 125s leaving the jump in 5th gear turning 11000 RPM more might see over 15,000 RPM when the wheel touched the ground.
Engines that are over-revved to the point to caused a catastrophic failure usually pull the wrist pin boss out of the piston, pull the connecting rod apart somewhere along the I-beam section of the rod or the rod breaks through one of the lubrication holes in the wrist pin end of the rod.
It looks like the wrist pin boss of the piston failed first, not the connecting rod. If the con rod failed first the wrist pin end of the con rod will usually be "opened up" and the wrist pin boss of the piston will still be in tack, with the wrist pin still in the piston.
When the piston becomes disconnected from the rod, it will sometimes hit the head so hard that it will pull the head studs out of the cylinder or pull the cylinder base studs out of the cases. I have also seen the tops of acorn nuts pop off when the piston hits the head in these types of failures.
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Sorry about your luck man. Hopefully you have a spare engine laying around so theres no down time.
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WOW!! No half-ass stuff there.
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Thanks for the humor guys! :joyous: The crying doesn't help!
My son was riding it, when this happened. He's an experienced rider. He was shifting through the gears, on a flat trail with moderate acceleration. Hits 4 gear and locks up. No over-rev. It was quick with no warning signs. I was running the piston with too much ring gap (.018). I should have had it bored, but was trying to get buy on the cheap. Dumb decision on my part. It doesn't appear the piston hit the head very hard. I don't understand how it caused so much damage, in such a short amount of time. I guess I'll be in the market for another set-up. How do I explain this one, to the wife? :cat::culpability:
Is it possible, the ring could have rolled over and got wedged?
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/F8CB31E1-40FD-4539-8C09-531887CFA144.jpg)
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Looks like theres quite a few scars on the dome with carbon covering them, what all happened the other times the piston was replaced.
Maybe I'm not seeing it that good from the pic, but the one of the rod, it looks like that bottom crack is kinda smooth, like its been cracked for a while & vibs have smoothed the cracked area out. Just dont have a ruff fresh crack look to it. Might just be how the pic looks.
Neil
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Thanks for the humor guys! :joyous: The crying doesn't help!
My son was riding it, when this happened. He's an experienced rider. He was shifting through the gears, on a flat trail with moderate acceleration. Hits 4 gear and locks up. No over-rev. It was quick with no warning signs. I was running the piston with too much ring gap (.018). I should have had it bored, but was trying to get buy on the cheap. Dumb decision on my part. It doesn't appear the piston hit the head very hard. I don't understand how it caused so much damage, in such a short amount of time. I guess I'll be in the market for another set-up. How do I explain this one, to the wife? :cat::culpability:
Is it possible, the ring could have rolled over and got wedged?
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/F8CB31E1-40FD-4539-8C09-531887CFA144.jpg)
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/BC2263B1-9F25-4E21-A228-10996B24DE45.jpg)
You could have put it together with 1/8" end gap and .020" piston to cylinder wall cleanrance and it would not cause that type of failure. If the ring had hung so hard that it stopped the piston on the down stroke it would have pulled the outer edge of the piston above the ring off before pulling the pin boss out of the piston. This type of failure is very common on engines with cast pistons, especially automotive engines.
The engine may have not been revving extremely high at the time of failure but the evidence tells me that it has been severely over-revved at some time. It may have cracked the pin boss area at some other time and it finally let go at a later time.
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Looks like theres quite a few scars on the dome with carbon covering them, what all happened the other times the piston was replaced.
Maybe I'm not seeing it that good from the pic, but the one of the rod, it looks like that bottom crack is kinda smooth, like its been cracked for a while & vibs have smoothed the cracked area out. Just dont have a ruff fresh crack look to it. Might just be how the pic looks.
Neil
Two piston change from overheating, from the ESR water passage restriction. This was the third piston, three hones on a 76mm bore. I think it must be the picture Neil, the rod beam looks ok.
You could have put it together with 1/8" end gap and .020" piston to cylinder wall cleanrance and it would not cause that type of failure. If the ring had hung so hard that it stopped the piston on the down stroke it would have pulled the outer edge of the piston above the ring off before pulling the pin boss out of the piston. This type of failure is very common on engines with cast pistons, especially automotive engines.
The engine may have not been revving extremely high at the time of failure but the evidence tells me that it has been severely over-revved at some time. It may have cracked the pin boss area at some other time and it finally let go at a later time.
Jerry, you continue to educate. I appreciate and value your opinion.
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Not the I beam part, right there on the small end, that bottom crack.
Neil
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I'll look at that area again, Neil.
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Wow that made a mess. Do you know what piston to cylinder clearance it had before the failure and what piston was in it? Just curious.
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Now that's an example of riding PINNED!!! Lol. That's a ton of damage man.
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Fred, you pulled that bottom end apart yet ??.
Neil
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Wow that made a mess. Do you know what piston to cylinder clearance it had before the failure and what piston was in it? Just curious.
No, not exactly. It was on the first bore (76mm piston) third piston. Honed lightly between piston installations. ESR's Wiseco piston.
Fred, you pulled that bottom end apart yet ??.
Neil
Not yet Neil. I'm waiting for the right mood. :crushed:
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No, not exactly. It was on the first bore (76mm piston) third piston. Honed lightly between piston installations. ESR's Wiseco piston.
Not yet Neil. I'm waiting for the right mood. :crushed:
So the cylinder not been bored again, just a little honing each time & new STD size piston. Good guess would be, the bore got a bit loose from the honing each time & that piston just gave up.
Hold your arm straight up, ball your fist up & then rock your wrist back & forth. That rock of your wrist, is what that pistons doing on every up & down stroke of the crank, even with the proper piston to bore clearance & soon or later that piston being the smaller lighter part will give up. Any time there is more clearance added, that rock gets worse. Be interesting to measure the bore on that sleeve just to see how much it is.
Neil
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I was rolling the dice, I know. My Hebrew ancestry (Jesus), got the best of me. :hopelessness: The money we spend to keep yourselves running :quad: happy, should never be compromised! Lesson learned. :tranquillity:
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What is this ESR water flow issue, your talking about?
Are the holes in the dome too small?
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What is this ESR water flow issue, your talking about?
http://trx250r.org/threads/331-ESR-330-Failure
Look at pictures in post #31 then go to #68
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And all esr for over a year have been changed even more then that over the ex including down into the jacket area.
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I dodged a bullet! Cases survived! :apathy:
(http://i532.photobucket.com/albums/ee328/RideRed187/250R%20Pics%20Parts/71FBDBA5-2579-42B1-ACC1-21B90CEE680E.jpg)
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Whuuuuu, thank goodness.
Not entirely though, check the roundness above & below the balancer cavity, got two bulged out places. Be sure to check for flatness & use a heavy coat of sealant going back together.
Todays the day Fred, mail runs kinda late though.
Neil
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ya almost looks like its alittle distorted near the balancer area. might just be the camera angle though
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Your right Neil. You can see that from 900 miles away. How's that going to effect anything? How bad is it?
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Is that the only cracked place on the right side half ?, what about the left side.
I know only a patch, would be good for just so long & the high dollar pocket folks will say replace them both, but its your money that will have to spend when just a little JB Weld would seal up the crack.
I would be thinking more about, if it has deformed the sealing surface for the gasket, thats why I was saying a good heavy coat of sealant on the gasket to fill any deformity.
Theres alway, V the crack, try to press the bulge back in shape & weld, but then you have to surface the gasket area back flat because the welding will push & pull the case.
Neil
Nothing came Saturday.
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That's the only crack. I can fix that up. Out for delivery today Neil.
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Did some testing with, JB Weld. Test sample sat in Honda HP tranny fluid, for 6 weeks. No change in appearance. Then I heated the sample in the fluid, [MENTION=677]250[/MENTION] degrees for 2 hrs. Still no visible changes. I sealed the crack up. Going to give it a whirl.
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