Ply318ci said:Yep the closer one is a 72 the farther one is a 74. Got the 74 for the cases (the 72 threw a chain and busted the case) and the 72 came with the bike. The seat was done by the PO who wanted to cafe the bike but lost interest and sold it.
stock 72 is most collectible but the least useful because there are so many parts that changed over the years. If you have a choice, use the 72 barrels and 74 crank but with 74 on pistons. You can't mix and match pistons and cranks across designs. 72 inlet manifolds are more like normal Mikuni intakes and are easier to change to larger carbs. Late (BS) carbs and early VM32 flow about the same and supposedly either can handle around 100 HP.
Transmissions changed in 75 and again in 76 and 77, but all will work fine on the street.