Same reason as for using an early cylinder on a bike:martdapp wrote:Welding the caphole to the other site is possible, I have such a tank. Then stays the fact that the hohle is to big for the NZ-1 petrol-cap as shown on the tank from the for sale NZ-1. I put in some pictures from my tank, it has indeed the older and wider caphohle and the holders for the knee-protectors. And also the old wire for the petroltap. But why and for what reason did they/some-one do that?
The early tank were produced 6 years, the later one just a year. It is even more difficult to find a late one, so many restorators seem to use the early one, with some modifications. That they keep the knee protectors is in my opinion just the result of bad research. The tank is NZ, and they keep them, ignoring that the late NZ does not have them.
The cap diameter is easy to change, you just need a second tank from a modern bike, as available at motorbike-part-traders and then you fit the new one.