bro its 78 cc
top speed i havent checked not that professional rider yet 
brake is good enough ! although i feel sometimes the rear tyre is a bit too thin !
net weight i didnt check bro
yes v durable till now although too early to say that , have tried a bit high speed on rough terain and it handled well , wuz quite smooth on the bumps which i didnt expect
the only and major fault in it is signs of rust starting to appear already ! other then that its great i am happy with it