Piston oversize

[Vonturd]

So I was on mixes xs pricing out parts for my rebuild. And I noticed the piston selection they have on there. For instance, they have piston 1st oversize all the way to piston 4th oversize.
well it says they fit models from 74-84. Well my question is will these pistons fit in my stock motor? And if they do what are the advantages?
I can only assume these are pistons for when you have bored out you cylinders?
Maybe I'm wrong..... Thats why I ask.
For my rebuild since I'm not buying a big bore kit should I just stick with the standard piston size?

 

[weaselbeak69]

I went from 1st to 4th oversize with no issues yet on my otherwise stock motor. If your cylinder walls look bad then boring the cylinder out will give you a nice smooth wall. One thing to keep in mind is you'll have to add the cost of the machine shop work to bore your jugs out and also the cost of new rings. I also needed larger jets in mine, not sure if a smaller jump in size would have required larger jets.

 

[TwoManyXS1Bs]

The best way is to take or send-off the cylinders to the machine shop, where they can clean-up, inspect and measure the bores. From that, they can determine if overbore is necessary, and how much. Then you (or they) order the appropriate size pistons and rings. Deliver them to the machine shop, since they will need to have them 'in hand' to bore the cylinders to proper size. They can also set the ring gaps when done.

A similar situation: http://www.xs650.com/forum/showthread.php?t=37382