The T-100 Bonneville has a traditional 360 degree firing order with both pistons going up and down together. One piston is at the top of the power stroke and the other is in the middle of valve lift overlap. The chopper style America and Speedmaster models and the scrambler have crank throws with a 90 degree offset like the one in the foto. These are typically run with a 270-450 firing order. The Triumph dirt track team does this. This is what I am doing this year. They can also be set up for 90-630 firing order. I might do this, too, at a later date.
The parts came back from Revco where they were balanced. Little drill holes and spot grinding indicate that work was done. They were balanced for the big bore pistons and the Carillo rods. These lopsided firing order twins are very smooth. This should be an almost vibration free race motor.
This conversion is costing me a lot more than I initially figured. The shed is being cleaned out and a few things are posted in the classifieds on the Triumph forum. There is no interest there. I will post them here, too, under the W. Walrus Shed Sale thread. A donation will be made to Slim if I can get rid of these most excellent items.