Yamaha SC 500

[maxvmx]

Apart from the tank colour and decals what's the difference between a 1973 and 1974 SC 500?

[Iain Cameron]

None that I know of it was just a follow on model . Iain

[YZB 500]

Hi ya,

Shift drum is longer on the 74, changes in the shift mechanism.

and the 74 went to a needle roller bearing in the clutch actuator shaft.

and some gearbox internals, close ratio to wide ratio

also the big end in the early parts books is a 19 needle roller bearing, give that a miss, the 17 needle roller bearing is the go! I had a 19 needle roller bearing big end fail, the cage is strong in the case of the later part numbered big end bearing.

Regards YZB 500

[bazza]

CDI unit and one was faster than the other! You could swap between 2 models and it made the difference in speed as to which would be faster. 2 mates measured barrel, ports etc trying to see why one model was faster,in end they found japanese info on CDI, swapped and it made the difference

[Iain Cameron]

Well you learn something new every day . thanks gents . Iain