12th overbore piston pins- can stock honda be used

2799 Views 10 Replies 4 Participants Last post by beedub, Jun 22, 2009

beedub

Discussion Starter · Jun 20, 2009

the overbore pins that come with the large pistons are really thick and much heavier than the stock Honda. Can the stock Honda pins be used ok? the piston bosses are large and thick, and it seems silly to increse the mass of the piston assembly by such a large factor. the fit is exactly the same, no slop there (see below!), and Hondas are a little shorter but not much, 1/8" ?

soemone also told me the pin holes are supposed to have a clearance of .oo4" but I don't think sooo...0004" I asked? no, .oo4". ok i said. good to know.

so anyone know about this? seems to me increasing the reciprocating mass a lot would be more likely to cause bottom end or top end failure in the rod assy.

thanks, bw

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Bird76Mojo

· #4 · Jun 20, 2009

Have you weighed the pistons too?

I'd just use the new parts. It won't make that huge of a difference unless you're building a race engine where maximum revs are desired.

GB :mrgreen:

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Bird76Mojo

· #6 · Jun 20, 2009

A 25 gram difference in total reciprocating mass is nothing to worry about IMHO..

GB :mrgreen:

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Bird76Mojo

· #8 · Jun 20, 2009

You must have wrote it wrong then. Check your previous post.

What I was getting at was this:

Stock pin: 107
Stock piston: 215

Total: 322

New pin: 147
New piston: 200

Total: 347

So you're saving 15 on the piston. Adding 40 with the new pin. All together, adding only 25g.

Adding a mere 25g is nothing unless, like I said, you're building a race oriented engine.

GB :mrgreen:

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