piston bore size???

[calholli]

piston says 3209A, but I can't find anything about it on google, ebay, ect..... the bore of my cylinder is nearly 67mm.. the bore on the piston is right at 66mm... so what size do I order from ebay, do they go by the piston or the cylinder???? I ordered a 72.5 big bore before, and they sent me a 72.44mm piston.. so I'm assuming you order by the cylinder size and they give you the correct piston. but IDK, cus a few dune trips later, that bb piston busted the skirts (and the cylinder sleeve skirts)... and I don't want that to happen again.. please help.

side note< ... can I re-sleeve my bb?? how much?? (otherwise I'm just gonna order this smaller piston.)

 

[calholli]

I cleaned the top of my piston and found some more numbers... 573m0??75 .... looks like a 6 then I can't read the second question mark, they're gone.. but searching I found mo6675 and it says its .030 over.. this is likely my piston, but what is stock?? any help would be great. thanks.

 

[hotrodaj_2]

You always go off of the cylinder. When a piston gets extremely hot they can shrink when they cool. They can change an a few other ways also. The cylinder can change but it will be very little at worst. Give someone your cylinder size and they will give you a piston, cylinder work may still need to be done, they will tell you ( make sure you ask). I think cast and forged piston are clearenced differently. Buy a forged piston, they are well worth the extra money imo.

 

[brandoz28]

also make sure they chamfer the ports too when you have it bored

 

[super noober]

stock piston/cylinder bore is 66mm, like mentioned stay away from sh*tty cast pistons and get a forged one.