Late Mk2a swingarm uses identical parts to Mk3 swingarm?

I believe I know the answer to this question. The later Mk2 & Mk3 bikes (mine is April of '74) employed the following parts:

= 06.5227 - Pivot seal
= 06.5320 - "Short" bush

The early Mk2 used the following parts:

= 06.0446 - Dust cover
= 06.0449 - "O" ring
= 06.0447 - "Long" bush

I was not able to figure out at which VIN number this shift took place. Doubt we can nail this down but was interested in knowing if the Mk2(a) swingarm changed in any way to allow this. For example, the "shelf" machined into the outside-facing sides of the swingarm? Also the distance between the inner faces of the swingarm (mine measures 4 1/8" face to face) - is this different from the inner measurment, face to face, of the earlier Mk2 (and beyond for that matter)?

Thanks and sorry if this has already been covered, could not find that thread.

My August 74 MKII has the pivot seal, welsh plugs and felt oilers, but the pivot is still drilled for the central fixing bolt. Sort of a 1/2 way to being MKIII bastard child.

My early February MKII has the wimpy o-rings and long skinny weak "bolt" holding the end caps (with the "never-to-be-greased" grease nipple) in place (barely!).

My understanding is during these transtional times, there was more than likely no hard VIN where all the changes took place, but that various bikes coming off the line would get whatever bits and pieces were still laying at hand around the factory at the time. Not too hard to believe given the much more relax assembly process being used in those days.

My Feb 74 is the old style complete.

Jdub said:

I believe I know the answer to this question. The later Mk2 & Mk3 bikes (mine is April of '74) employed the following parts:

= 06.5227 - Pivot seal
= 06.5320 - "Short" bush

The early Mk2 used the following parts:

= 06.0446 - Dust cover
= 06.0449 - "O" ring
= 06.0447 - "Long" bush

Click to expand...

Correct, plus the other parts including the 'short' central hole spindle, (or latest type that fits both late Mk2/2A and Mk3) also felt wicks and welch plugs.

Jdub said:

I was not able to figure out at which VIN number this shift took place.

Click to expand...

The number (if one exists) is still as yet unknown.

Jdub said:

Doubt we can nail this down but was interested in knowing if the Mk2(a) swingarm changed in any way to allow this. For example, the "shelf" machined into the outside-facing sides of the swingarm?

Click to expand...

Yes, there's a difference. The part number for the later swingarm is unknown.:
']

https://www.oldbritts.com/mk3_sa_lube.html

Jdub said:

Also the distance between the inner faces of the swingarm (mine measures 4 1/8" face to face) - is this different from the inner measurement, face to face, of the earlier Mk2 (and beyond for that matter)?

Click to expand...

The 850 Mk3 is the same (4 1/8").

My Feb. '74 MkII has drilled pin, wick oilers, no long lock pin. It's a wonderful world we live in where giants once roamed the land unfettered. Swingarm is MkIII type with recess.

maylar said:

My August 74 MKII has the pivot seal, welsh plugs and felt oilers, but the pivot is still drilled for the central fixing bolt. Sort of a 1/2 way to being MKIII bastard child.

Click to expand...

Ditto my 04/74