The timing bracket is difficult to hold
The only bit with any surfaces to clamp on is the clamp at the bottom. So that needs squaring up first.
Then there is little choice where the mounting hole is going to go as that only has about 1mm to come off the inside diameter
While it is mounted up best drill the holes relative to the mount. This can then be used to hold the bracket to turn the back face. A bit more drilling/tapping, then the clamp can be slit.
A quick check it fits - I needed extra clearance around the bolt heads behind the bracket, then I need to think about making some mounting screws
Jo