Super happy with the first lower bracket mockup, it's dead on.
Doppler engine spring tension is perfect, carburetor bowl and launch lever linkage clearance are perfect, exhaust ball joint and radiator clearance good as well.
I'm gonna use that template to fabricate 2 thicker plates bolted on each side on the engine cases + a spacer between them to mount and secure the launch lever ball joint.
I'll also be able to adjust the spring mount and launch lever for 2 different diameter size clutch pulley, from Doppler 195mm to C.Bouchet 175mm roughly, using the same 17mm scooter belt length.
The pipe is not final, I haven't even started working on it. I'll play the volume, total length, probably stinger diameter. I have MORE pipes to test and play with til I get the right one for that setup. I'm not looking for a screamer but a torquy and reliable track engine that can last one or two entire seasons, not just a 1/4 mile race and rebuild :)
Pretty the same as all my previous 50cc race track engines, fast, reliable, low maintenance.