I'm planning to build up a race bike from an Ancillotti 125 cc (Hiro engined, 1978) motocross bike. I will convert he engine (34 hp without tuning!) and the frame and buy or make all the other parts. So my project will take a lot of time and money. (Fortunately I have a pre67 racer to ride while building this new racer.)
I'd like to find a model (for the appearance) from the latter half of the seventies. Do you have in your mind a good-looking 125 cc race bike from that era?
Greetings Andres. Beauty is in the eye of the beholder. What rules are you building your bike to? Most national motorcycle associations have their own rules. By Australian historic competition rules the bike has to have the external appearance of a model from the era or at least use parts that are externally "visibly indistinguishable" from parts of the era. To me the Morbidellis were the best looking 125 road race bikes of the 70s with alloy wheels and disc brakes. But by the Australian rules, as we have to use 18" wheels in our Period 5 class ('73-'80) and it is hard to find suitable (lightweight) 18" alloy wheels, most builders use spoked wheels. RS 125 Hondas became available in 1980 and are probably the most suitable to base your bike around to visually conform with Australian rules. As far as looks go - a lot can be done with paint & stickers on the bodywork of the era. Good luck with the project. Bummers
Assuming you are building a road race bike
“Racing is life. Anything before or after is just waiting.” Steve McQueen