During the 1960's Yamaha supplied many so called GYT kits for many models, but when the "real" race-kit parts became available for the AS1 everything changed.
After purchasing an AS1 or later, the AS3, one could build a very competitive 125 cc racer. In Europe, few people modified standard bikes, but many riders built very smart looking AS1 and AS3 based racers. I have a lot of pictures of these bikes and will add those in due time.
From the accessory catalogue of the Dutch Yamaha Importer at that time, Messrs "Het Motorpaleis" (the Motorpalace) of January 1972 is this listing of the AS3 tuning parts. It is not necessary to translate it (I think) as most of you know Yamaha partnumbers........, but here they are from top: Engine: cylinderhead-cylinder left-cylinder right-pistonring-piston-conrod-bigendbearing-carbmanifold-clamp-carb left-carb right-clamp-clip-holder-carbrod-racemagneto Gearbox and Exhaust: wheel 1st gear-wheel 5th gear-wheel 3rd gear-wheel 2nd gear-main axle-5th gear-2nd gear-clutch spring-friction plate-clutch plate-exhaust left-exhaust right-exhaust screw-exhaust spring-exhaust bracket
The price of a complete AS3 engine was Dgl 1195,- and the complete tuning kit was priced at Dgl 1295,-, but that was January 1972!
Here is a good picture of the contents of the kit (here the slightly older AS1 kit)
The most extraordinary part was the beautiful racing magneto, recently I received this picture of a brand new one.......!