Mike,
I went to the German Webra site and I agree the 91 looks like a winner with the TNII carb. My 32 is sweet and the TNII carb on it is great. I did not see a price or ordering info... I would keep the fixed gear if your inverting the engine as the damage to the engine and firewall would be significant of the retracts malfunctioned and you had to belly it in. Pete