2 Stroke Single - Overbore Opinions

The rings are VERY worn on the RV125 I am rebuilding. So I am going to bore it out since its the proper thing to do.

Should I:
1) Bore to the next size .5mm over
2) Go all out and bore to 2mm over

Will there be any significant power increase with a 2mm overbore? Is it worth it? I have no experience with this on 2 strokes so I'm looking for opinions.

Just go the next step up if the cylinder is un damaged.
You will gain like 2cc per step or so, so its not really going to get you more power.


Plus if it wears, you have no more room to go over anymore

Always go with the smallest overbore that will get you full cleanup. That way you can get more "life" out of the cylinder. Most guys that do cyl. boring would like to measure it first and then tell you what size piston to purchase.

Thanks guys, just what I wanted to know. Appreciate the input.