i bought literally the first athena. not to run but to compared to the cylinders they copied poorly (vitos).
i wrote this in 2009 on another forum when i got them:
the description of the piston is wrong they are NOT forged moly coated pistons, they ARE a o.e.m. style(68mm though) CAST piston with a cheap tin coating. the intakes are too short to accept a stock reed cage. the larger water jackets that are mentioned are actually to small to use a stock water jacket plug and the kit doesn't supply any plugs so theres no way to keep this cylinder from leaking. the left cylinder has egg shaped intake bolt holes with threads only on the top portion of the screw cavity, intake bolts will thread in by hand but id bet they would strip if a allen wrench was used and they were tighten. back to the bore and piston, because of the piston they use and the triple ports its going to be short circuiting like crazy. the stock looking head with domes looks pretty good except that the domes are different then pro-design,vitos,modquad,noss etc. etc., they were 24cc also. theres alot more i could say about these but i'll stop here, if you want to pm me we could talk more.