Author Topic: The Aftermath, Carnage! :culpability: (Read 13920 times)

F-Red · « **on:** January 10, 2015, 01:43:08 PM »

Words to follow! :miserable:

havinnoj · « **Reply #1 on:** January 10, 2015, 01:49:49 PM »

Whoa.. let's hear the story behind this one F-Red!

zaT · « **Reply #2 on:** January 10, 2015, 01:56:00 PM »

Damn!

Pumashine · « **Reply #3 on:** January 10, 2015, 02:07:32 PM »

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.

Hawaiiysr · « **Reply #4 on:** January 10, 2015, 02:07:34 PM »

Oh my...

Piney0 · « **Reply #5 on:** January 10, 2015, 02:27:00 PM »

Wow. Ouch. I have never seen a rod break like that on a single cylinder 2 stroke.

Rupp250 · « **Reply #6 on:** January 10, 2015, 02:38:55 PM »

Little muriatic acid on that cylinder and it will clean right up.

:lies:

2ndmoto · « **Reply #7 on:** January 10, 2015, 03:04:29 PM »

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

dirtyd · « **Reply #8 on:** January 10, 2015, 04:08:44 PM »

now thats what I call grenading a motor. damn

JesseA420 · « **Reply #9 on:** January 10, 2015, 05:06:39 PM »

rub a lil jb weld on her, she should be good as new

jcs003 · « **Reply #10 on:** January 10, 2015, 05:20:05 PM »

time for a lil forensic engineering.

John

Jerry Hall · « **Reply #11 on:** January 10, 2015, 05:45:08 PM »

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.

broken1 · « **Reply #12 on:** January 10, 2015, 09:02:38 PM »

Sorry about your luck man. Hopefully you have a spare engine laying around so theres no down time.

StrokedAZ · « **Reply #13 on:** January 11, 2015, 01:03:56 AM »

WOW!! No half-ass stuff there.

F-Red · « **Reply #14 on:** January 11, 2015, 10:32:19 AM »

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?