TOPIC: Drive Train- featherbed

featherbed/Wide line engines and codes
500cc code 12-2 and 600cc code 14
Code is on LH side of case under barrel. Later ones are adjacent to patent badge on case.

Note 2 types of engines for each size. dynamo cases with stubby crankshaft and later alternator cases and longer crankshaft.

featherbed/Slim Line engine codes (all are now alternator cases and crankshafts)
1. The shop build type identification and serial # is on rear of the case
Then:
500cc code12-2 and 600cc code 14
AFAIK they all now had patent badges on LH side of engine cases.
finally when the engine was assigned to a bike rolling chassis The frame was VIN stamped with the engine type and engine serial #. However they were given a marketing name such as 88 or 99 "BIKE"but the frames were stamped same as the as engine #

650cc engines introduced with slimline only which is assigned code 18 but installed in "manxman, "650SS" or 650 named bikes. Rolling chassis numbered with 18 matching the engine code, again stamped with brit serial # US VIN from engine
Still confused by most to this day...........

650 last of the "DOMI" small bolt pattern barrel and head engines.

I see no logical reason to name a BIKE a domi when it is actually the ENGINE..
1961 type sn
94449 18 65 123 Manxman ebay calif
94516 18 65 193 Manxman
95109 18 65C 329
97912 18 65 481

1962
100213 18 650C 793 dd

1963
104172 18 650SS 1899 ..dd......

The slimline 750 was code 20 but it's piston bore configuration is new as a DESAXE. This is where the piston bore size increase is moved primarily to the rear. It therefore resulted in a portion of the head bolt pattern getting larger- rearward.
The 20M1 was to have been designated when there became a 20M2.
If correct? The 20M2 had concentric carbs and rear point instead of a magneto. These additional evolutionary changes and upgrades happened but were not as "celebrated"
.
20M3 will later become designated as the first 750 engine series in the commando rolling chassis.