[Jordan1200]

If I do a big bore upgrade from a 96" to 103". Is there any Benefit in the way of noticable power gain when going to the biggest over sized pistons .010" over or would I be better off to stay with standard bore for durability and cooling?
I do like the idea of keeping the cylinder walls as thick as possible. I know you can take the stock bores to 107" but again I worry about reliability and longevity of my motor...not to mention that I would have to reeplace the entire cylinder if I had mine bored to 107" and needed to go oversized in future as opposed to a small oversize boring..
Additional question.
I have used stock pistons in the past for my 883 Sportster 1200 Buell Thunderstorm top end conversion.
Is that a good way to go or are there better materials in the aftermarket to use and if so, what is better about them keeping in mind thermal expansion and other attributes of course.

 

[troqed]

Os pistons are to make the bore fresh and usable.
SO .010 over will add nothing.
The big bore of course will.

 

[Don Dorfman]

At 3.937 you grow to 107", a few more horsepower. KB makes a nice heavy duty line2line coated piston for those.

 

[troqed]

For mediocrity (Poorly built) will get one-to-one.
1.25 is average and anything above that is getting really good .
Harley in their sales campaign are the only people that i know of that will sell a bike leaving half the power
on the table so a stupid customer will come back and buy the bike all over again.
Their bikes have always gone out the door anemic with a pellet of Scamming eagle parts waiting in the back room.
those that buy new bikes should demand the crap be bolted on NOW at the sticker price.