| Diagram | Fig. 14 — CLUTCH · ref 5 |
| Subsystem | primary |
| Listed in parts books | 1974, 1976–1980, 1985 |
Sprocket and housing
Sprocket and housing (chainwheel) for the clutch primary drive, carrying the triplex chain into the clutch assembly.
57-4640 is the sprocket and housing assembly that sits in the clutch on the primary side of the engine, listed in the CLUTCH section of the parts book. It carries the triplex primary chain drive from the engine sprocket back to the clutch, so this is the piece the chain actually wraps around before power gets to the clutch plates.
Read more
Catalog records show this part number appearing across rows from 1974 through 1985, so it had a long run in the parts books. If your parts book lists 57-7065 alongside it in the same clutch section, that's worth checking against what you pull off the bike, since more than one number has shown up tied to this assembly over the years.
As with anything in the clutch and primary area, get the correct one in hand and compare it to what comes off the bike before you order, especially if you're not sure which chainwheel style your primary case was built around.
Sorry if we got something wrong here. If you think this information isn't correct, .