So just to recap. this was my first scratch built frame. Constructed out of 5/8" tubing, I built the frame using a simple wooden jib I fashioned up. I raided the parts bin for the main components, like the Yamaha GT80 engine, Honda S90 tank, forks, swingarm, and hubs. I think the headlight is off a Bridgestone 90, and the seat was of course built from poplar wood, is despite its chunky appearance is quite light thanks to be mostly hollow inside each layer.
Wheels are 2.15x18 aluminum rims laced to S90 hubs, sporting Shinko 244 tires in 3x18 size.
I went a little crazy with the engine, upping compression from a meager 7:1 up to around 10:1 thanks to shaving down the head and fitting a slightly domed piston. I also opened up the intake and exhaust ports, and did a little filing on the piston to change the port timing per some race specs I found for old 80cc Yamaha engines. It really does scream. Well, as much as say 10-12hp or so, by my estimate. Which is a lot more than the 4.9hp it made stock, with the tiny little carb.
Speaking of, yes, I have an air cleaner for it. But it is currently sitting on the DKW acting as a space saver during mock-up.