"mike" wrote in message
...
"Mike" wrote in
:


Not necessarily Mike.
There've been lots of non-360 degree twin 4 strokes.

This particular engine has both pistons going up and down at the same
time. I am pretty lame in motorcycle knowledge. What well known
parallel 4-stroke engine type use the opposite, one up and one down?
Sound must be quite distinct.

O=={o] Hot Rod


Early triumphs had both 180 ( pin 180 apart ) and 360 (pins together
alternate firing). Some laverda 500 racers had 180 cranks. Yamaha 850 twin
and Triumph Bonneville america have 270 cranks where the crank pins are 90
degrees apart..... they sounf like a V twin

Are you sure about the early Triumphs? My '56 pre-unit had a 360 crank.
I've never heard of any Triumph with a 180 crank, but I've never heard of a
lot of things. You're absolutely right about the Laverdas though. I seem
to remember a model test done by a bike magazine on a street model parallel
twin Laverda back in the '70's that stated that it also had a 180 crank.

Garrett Fulton

Garrett Fulton