| Also known as | 54202299C |
| Diagram | Fig. 1 — CRANKSHAFT AND CONNECTING RODS · ref 22 |
| Subsystem | engine bottom |
| Listed in parts books | 1968–1970, 1976–1978 |
Rotor, type RM21
RM21 alternator rotor for the crankshaft, later superseded by part number 54202299C.
This is the RM21 rotor, listed in our records under part number 99-0739 and later carried forward under 54202299C. It shows up in the crankshaft and connecting rods area of the parts books, as well as under crankcase listings, which tells you this is an alternator rotor mounted on the crankshaft rather than a separate generator unit.
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The RM21 designation refers to the Lucas alternator rotor type used on these engines. It spins with the crankshaft inside the primary side of the motor and works with its matching stator to generate the bike's electrical current.
Our catalog shows this part appearing across a run of years from the late 1960s into the late 1970s, but we don't have the specific model-year breakdown pinned to this listing. If you're chasing down a rotor for a rebuild, check your original part number against 99-0739 or 54202299C before ordering, and give us a call if you want us to confirm fitment.
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