Chainsaw Repair

IF 5100 is 45 x 32 shows 50.91   477816393442   I always thought jonsered 590 was 45 x 32 and 50.7cc by their paper work specs. But calculator I use says 50.9. 

I have allways believed the 590 and 2051 were 50.9cc, despite some statements saying 50.7 or 50.8.

Regarding the Dolmar, I have never seen any statements from Dolmar regarding the exact bore/stroke, but they have stated anything from 49.9 to 50.7 regarding the cc, depending on which document you are looking in.
My guess is that the bore is closer to 45 than it is to 44mm, and the stroke 32 - but the exact bore is an open question.....

I assume these saws are just over 50cc because of the way EPA rules works.