Engine rebuilding checklist 750 Seca

I am currently at the point where I have almost all the parts I need to rebuild the spare engine for Pumba, and started thinking along the lines of while its apart why not replace ???

An example is reading about selector return springs failing, should I get a new one?

So what would you consider a must on a rebuild (I wan't this rebuild to outlast me)

Already have;
Gaskets/seals
Bearings
Pistons
Serviced head
Timing chain
Primary chain and guide
Starter clutch bits
New rod bolts and nuts
Oil pump chain
Clutch pushrod and bearing

Suggestions?

 

Put a polish on the piston crowns and combustion chambers which marginally boosts efficiency and keeps carbon from sticking.
Did you remove any minor imperfections from the intake and exhaust ports??
You didn't mention a new clutch.
Put a few magnets in the "oil pan" that will collect extra iron shavings from all the chains, sprockets and gears.
"blueprint" your oil pump??
Now would be the time to buy the "middle gear set" from a 900 so you have about 8% taller gearing.
Make the motor "yours".

 

This is a statement I've heard a few times: "Years ago, Continental Motors(aircraft) found that polished pistons had a higher failure rate than ones with a dull finish. The reason was of the boundary layer that insulated the piston crown from the combustion heat. A polished crown would absorb heat and melt/burn thru."

True, or not?

Googled around a bit, and polishing pistons seems to be another one of those things that some people swear by, and others dismiss, and nobody seems to have any empirical data for.

 

And a second question.

I now have a Wiseco big bore kit.

68mm pistons is a big cut (3mm oversize)for the barrels.
I know the 900 barrels are the same height as the 750s, does anyone know if the steel liners on the 900 are thicker/require less reduction of cylinder wall?

 

Dark would that not be a 1.5 mm cut in the barrels? As far as pollishing the piston tops why not ask Wiseco about that

 

Yep a 1.5mm cut, but it would only be a 0.5mm cut on 900 barrels.

Being air cooled I would rather have as much metal as possible (thermal mass).

Wont be polishing pistons, the Wisecos have a lovely machined finish, here is a pic showing them next to new yamaha units.

 

Pretty looks like your going to gain some on compression ratio