How many modern retro motorcycles are still being offered today?

[flynrider]

The British twins really thumped because both pistons rose and fell at the same time. The crankshaft flywheel on my BSA Lightnings was huge and heavy. But that's what gave them their great torque, that lumpy feel, and gorgeous exhaust note.

I rode my friends Yamaha 650 one day and it felt wimpy because of the opposed pistons.

My CB500XA was very smooth for a twin. It did not have the same strong feeling as my 650cc BSAs, but it was quick. Both were supposed to be 48 horsepower, but the 500 had fuel injection and a 6-speed transmission.

I believe the Yammie XS650 had a 360 degree crank, with both pistons rising and falling together.

My KZ750 twins also had this configuration. The primary vibration was rough. Eventually causing some parts to fall off due to metal fatigue.