Author Topic: The Aftermath, Carnage! :culpability: (Read 13916 times)

C-Leigh Racing · « **Reply #15 on:** January 11, 2015, 12:06:49 PM »

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

Jerry Hall · « **Reply #16 on:** January 11, 2015, 05:25:00 PM »

Quote from: F-Red;48590

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?

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.

F-Red · « **Reply #17 on:** January 11, 2015, 08:04:33 PM »

Quote from: C-Leigh Racing;48596

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.

Quote from: Jerry Hall;48603

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.

C-Leigh Racing · « **Reply #18 on:** January 11, 2015, 08:27:52 PM »

Not the I beam part, right there on the small end, that bottom crack.
Neil

F-Red · « **Reply #19 on:** January 12, 2015, 12:56:52 PM »

I'll look at that area again, Neil.

Bio86 · « **Reply #20 on:** January 14, 2015, 08:33:11 AM »

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.

pinned250r · « **Reply #21 on:** January 14, 2015, 09:27:57 AM »

Now that's an example of riding PINNED!!! Lol. That's a ton of damage man.

C-Leigh Racing · « **Reply #22 on:** January 14, 2015, 08:01:12 PM »

Fred, you pulled that bottom end apart yet ??.
Neil

F-Red · « **Reply #23 on:** January 15, 2015, 01:02:16 PM »

Quote from: Bio86;48686

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.

Quote from: C-Leigh Racing;48724

Fred, you pulled that bottom end apart yet ??.
Neil

Not yet Neil. I'm waiting for the right mood. :crushed:

C-Leigh Racing · « **Reply #24 on:** January 15, 2015, 01:23:19 PM »

Quote from: F-Red;48762

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

F-Red · « **Reply #25 on:** January 16, 2015, 01:03:49 PM »

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:

CR500R · « **Reply #26 on:** January 18, 2015, 12:57:05 PM »

What is this ESR water flow issue, your talking about?

Are the holes in the dome too small?

F-Red · « **Reply #27 on:** January 20, 2015, 01:07:01 PM »

Quote from: CR500R;48911

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

etccb · « **Reply #28 on:** January 20, 2015, 02:00:48 PM »

And all esr for over a year have been changed even more then that over the ex including down into the jacket area.

F-Red · « **Reply #29 on:** January 31, 2015, 01:17:46 PM »

I dodged a bullet! Cases survived! :apathy: