SOHC.co.uk Forums > CB750
750 K2 Strip & Rebuild - help please
K2-K6:
Haven't looked in detail at them, but peaning will easily do this.
Regarding method though, ideally it would involve peaning round the ball in one operation.
Imagine a ball bearing that's larger than the one used in the hole, with a hole bored in itself, placed over the crank and ball assembly, then when you thump it (technical term for lumping it one ;D ) it's own surface will compress the ring around the installed ball to pean the surrounding material in place to hold the ball and make it oil tight.
It's basic riveting really, but with a different "snap" set to give the required metal displacement. This stuff is pretty routine on steam boilers etc, implemented properly been holding stuff together since the industrial revolution ;D
Guess you could call it "angular riveting" and that would certainly make your eyes water :o
Ballls actually seal really easily, another example is 1/4 turn ball valve in plumbing.
The issue with threads is that it cuts into the structure and makes a stress raiser all round the pointy section. Why you're unlikely to see threads cut into conrods etc.
Honda obviously okayed that though on the late cranks from observations further back.
K2-K6:
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That one on the right hand side looks like the arrangement you'd need. It can't touch the ball though as you don't want to push that inwards just set the material uniformly around the ball to enclose it.
Oddjob:
The cranks though Nigel are peened using 3 strike areas, well it is on the 500 crank. Seems they just used a centre punch.
Trigger:
You just use a center punch at 3 points ;)
K2-K6:
:) no wonder they don't mind threading them then.
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