Pro china class bike build 1

Last post for the day! I had a bit of time left after the other two bikes were worked on to put in a bit of time on one of my team bikes.

This particular one is for the Pro chinese class. that means it has to be a chinese made mini moto but regulations regarding the engine are fairly open. that means certain parts like the crankcases and engine barrel must be chinese made (but can be modified) where as the bolt on bits like exhausts, carbs etc can be European or genuine brand items.

The bike im using as a starting point is a ZX-1 Taipan which is a Chinese made replica of a polini 911 dreambike. I chose it A) because i own one already and B) its the lightest water cooled bike you can get. So with the limited horsepower provided by the chinese based engine a light bike is a big bonus!

This bike already had a set of good quality banshee SHO wheels on it as opposed to the standard cag like wheels they come with, which is great from a strength perspective - unfortunately they don't accommodate a rear wheel driven water pump pulley like the stock one so some modifications had to be done.

The water pump pulley itself was from a DM mini moto and it mounts as a tight press fit behind the sprocket on a circular part of the hub. This wheel however had a tapered hub with 3 "stubs" on it so the pulley wouldn't fit at all. The solution was to jig it up in the lathe carefully and turn a flat area on the hub upon which the pulley could sit.


Here the machining is nearly done. The metal was getting quite thin near the bolt holes so i also took some metal out of the inside of the pulley as well and in the end it all came out great. you can see the flat areas where the pulley sits on in this picture.


And it fits! plenty tight too. Some pulleys mount by bolting to the sprocket itself, but this way makes it faster to change the sprockets at a race as it stays with the hub. To lock it on even tighter the pulley sits a thou or two above the surface (an extremely tiny amount) and the sprocket clamps it on tight.

Below you can see the finished product with everything bolted up. One problem i had when i put it together was that the wheel sat too far to the left because of the hub offset which made the pulleys and sprocket run misaligned. Remaking the spacers out of 2024 aluminium to replace the steel items (every bit counts!) and milling down the brake bracket made everything line up.

All it needs is a tire and new brake cable and the rear end is done!


Thats it for today. thanks. if you have any questions at all email me at Glen.M.R@gmail.com