boostein wrote:i have done this. i used a degree wheel to verify that the #2 cylinder intake valves close 180 degrees after the #1 cylinder.
Crank shaft angle or cam shaft angle?
I was a Yamaha XS-500 owner in late 70'. It was twin inline engine but not the same way like Triumph twins. When one piston was on the top the other was on the bottom. That means that you have ignition on 0 and 180 deg of first crank rotation and no ignition during second rotation. Engine looks like first two cylinders of four cylinders engine. Triumph style twins looks like four cylinders engine without first and fourth cylinder.