- Hard to do without a tear down and they are all about the same
anyways. The numbers won't tell you. The early engines (70-73) had
76cc heads and the later (74-76) had 120cc heads. The 120cc heads
had a bump in the exhaust port floor where the early ones was almost
a constant square port. Except for the heads almost all 500 are the
same and can built to the same levels but you have to be carefull
what pistons you put with what heads.
75 and 76 had electric chokes.
The 1970 did not have any smog pump holes in the head, but some of
the 1976 did not either.
Can't think of anything eles right now.
> Can anyone help me date the 500 I just bought?