How works the transmission?

While I had the 750 apart on the bench this weekend, and for no good reason at all, I documented the workings of the transmission in more detail. These gizmos can look confusing, but are fairly simple bits of steel. As most everybody knows, there are 3 shift forks operated by the grooves in the shift drum. The forks are labeled 1, 2 & 3, but those don't necessarily corelate to the gears they operate. Fork 1 is for 2nd gear. Fork 2 is for 4th & 5th gear. Fork 3 is for 1st & 3rd gear.

Each of the two transmission shafts consist of a gear that is rigidly fixed to the shaft, idler gears, and sliding gearsets which are splined to the shaft and engage their neighboring idler gears via dogs.

Here is the main shaft in the upper case half, with the large clutch gear on the right. The clutch gear is turned directly by the gear on the crankshaft. The middle gear is at the top.

The individual gears, 1st through 5th, are indicated along with their matching pair on the countershaft below.



Here is the counter shaft in the lower case half, along with the 3 shift forks. The two outside forks operate splined gearsets on the countershaft. The middle fork operates the splined set on the main shaft after the two case halves are mated.



In neutral, all the sliding splined gearsets (shown in orange) are in their middle positions, not engaging the dogs on either side. The idle gears are shown in blue. The gears fixed to the shaft are green.

Ratios between gears are as follows (particular to the '82 Maxim 750)

1st - 16/35 = .45
2nd - 20/30 = .6
3rd - 26/30 = .87
4th - 30/28 = 1.07
5th - 32/26 = 1.23



In each gear, shown in order below, the sliding of the gearsets via shift forks is indicated by the black arrow. The gears that are engaged in power flow are red.