80-81 125 RV

[Bill Campbell]

Can anybody out there provide me with some set specks for the above motor. I have a Bing carby and a standard motoplat external rotor ignition on it.It will start easily but will not rev out past about half throttle. It has a 160 main in it and running 2.5mm BTDC. Any ideas. Motor is fresh but I cant get it to run properly. Cheers