What causes a wrist pin clip to break?

[Rhino89523]

Half was still in the piston the other half was floating around in pieces, what causes a wrist pin clip to crack or break?

[AlisoBob]

They should be installed with the opening at either 12 or 6 o'clock...

If they are installed ( or wiggle around) so the opening is at 3 or 9 o'clock they fatigue under the flutter of changing directions 16,000 times a minute.

[Rhino89523]

Thank You, as always your the man. I'll make sure it goes in that way.

[2strokeforever]

i always install mine like that, they never come out like that, bugs me but no issues so far

[jbsleddin]

They should be installed with the opening at either 12 or 6 o'clock...

If they are installed ( or wiggle around) so the opening is at 3 or 9 o'clock they fatigue under the flutter of changing directions 16,000 times a minute.

Had one break on an old KTM when I was a kid, costly mishap. I just tore down a motor yesterday and the guy "freshly rebuilt" it. Cylinder was bored to the max, new piston etc. and he couldn't figure out why he could not start it. Compression was 60 lbs at best so I tried a leak down test which it failed miserably. Tore it down to find a new piston, gouged to hell, a ring that was not checked for end gap and had been butted and bent causing the lack of compression. Good thing that he didn't get it running because the one circlip that wasn't installed with the opening to match the slot in the piston (ten o'clock) , was half out of the groove and would've popped out wreaking more havoc. Minor scratch in the sleeve from the ring, hoping to just hone it and run a new piston. Oh yeah, almost forgot to mention, the new gaskets mustn't have been up to his QC standards, as they were slathered in silicone much similar to ribs ready to grill. Lower end and crown of piston were covered with the excess that squeezed out and balls of the shit would have been everywhere.... Some people's kids.

[Tharrell]

The postion is really important but I think most of the ones that come loose are not seated properly in the groove.

[Rhino89523]

"slathered in silicone much similar to ribs ready to grill."

[hoofarted]

Tore it down to find a new piston, gouged to hell, a ring that was not checked for end gap and had been butted and bent causing the lack of compression. ... one circlip that wasn't installed with the opening to match the slot in the piston (ten o'clock) , was half out of the groove and would've popped out wreaking more havoc. ...new gaskets...were slathered in silicone much similar to ribs ready to grill. Lower end and crown of piston were covered with the excess that squeezed out... Some people's kids (need their toolboxes welded shut)

Fixed.

[lunatic]

I asked K&T performance about circlp position and they said it dont matter.They have built thousands of motors so who do you believe?

[jbsleddin]

Any "mechanic" I've ever spoken to over the years has always said it doesn't matter, as long as the opening is facing up OR down, not aligned with the cutout like I keep finding more and more dumbasses doing. And then it's damn near impossible to remove the clip after when you have nothing to grab on to. As far as the clip that broke, I have no idea why since the remainder of the clip was still in the groove.