Although progress over past couple of weeks has been slow, I have made some decent steps forward. Firstly I won an e-bay auction for a Honda CBR600 frame, which I decided would make the perfect front –end for the project. The twin disc and decent telescopic forks will make a substantial improvement over the C90 drum and leading link set-up. Here are the parts cut ready for fabrication.
Secondly, I have arrived at a reasonable solution for the rear spring/damper unit which I am mounting in the lower body section. Initially it seemed to conflict with the location of the intermediate shaft, but I have been able to fit both items.
The intermediate shaft is needed to align the engine gearbox sprocket with the chain to the rear wheel. When centralised, the engine is too “slim” for the 160 rear tyre, and the chain dimensions would require custom sprockets making. I have solved this problem by driving the intermediate shaft (loose awaiting final machined spacers before welding) with a standard C90 chain and two engine sprockets. The original Z750 front sprocket is then fitted to the intermediate shaft and drives the stock chain and rear sprocket.
This allows more opportunity for gear ratio alteration to match the std 3speed box and target top speed. It also allows the opportunity of fitting an additional drive source (eg: electric motor) to further improve efficiency – but that’s more than I want to take on at present