50cc racer

[elbert]

I finaly got started on my 50cc racer project. It will be based on my old AC50 moped that I picked up from my parents place after it have been stored there for the last 12 years or so.
I've have an almost compleete RT kit for it which should result in something close to 10.5hp at 12000rpm.
Modifications will focus on removing weight and upgrading the front brake to either a bigger drum or a disk brake.



In the picture you can se the bead blasted and primed frame together with the expansion chamber, cyllinder with head and the clucth cover that alows for a 20mm carburator instead of the original 16mm.
I'm missing the disc valve from the kit, but if I can get the timing for it I will just cut an original one to the same spec. Apart from cleaning up the ports a bit the engine will receive an electronic ignition.

Any input on the project is apreciated.

[advant63]

i can help you with the first few grams. the m12 has a steel pipe with spring pins for the front seat mount. lighter than that bar on the A model.
i put a k or m swing arm on my a100. it is shorter, and presumably lighter weight and quicker steering. it may be the same as the 50. i can take measurements if you need.

[elbert]

Using a pipe instead of the bar seems like nice trick, I haven't been thinking much about the seat it self yet, probably make one from scratch.
For the swing arm a friend of mine offered to make one out of aluminum but I'm not sure if it will happen or if it will be any lighter than the original.
I will try to find a lighter front end for it, the fork legs are only 65 cm long so it's not a huge selection out there, but each leg is 2,2kg dry so hopefully I'll find some where the lower leg is of aluminum instead, maybe from a smal MX bike. Off course I'll be using aluminum rims when rebuilding the wheels.