71 Fastback rear isolastic

Yes, may need some changes for a 71 as this is for a MK3 but I suspect you will be fitting verniers type anyway.

https://www.accessnorton.com/NortonCommando/isolastics-mkiii-vernier-servicing.840/#post-6048

1. REMOVE THE TANK.

2. REMOVE THE PRIMARY (OPTIONAL -- SEE BELOW).

3. REMOVE THE HORN (OPTIONAL -- SEE BELOW).

4. REMOVE THE AIR FILTER(S) AND THE EXHAUST PIPES.

5. PUT THE BIKE ON THE CENTERSTAND AND FASTEN THE CENTERSTAND WITH SAFETY
WIRE, ELECTRICAL TIES, BUNGEE CORDS, ETC., SO IT CANNOT POSSIBLY
COLLAPSE.
DO NOT FASTEN IT TO ANY PART OF THE FRAME, BUT ONLY TO THE ENGINE PLATES
OR
SOME OTHER PART OF THE BIKE THAT HANGS ON THE ISOLASTIC MOUNTS.

6. SLIGHTLY LOOSEN THE NUTS ON THE LARGE CENTRAL BOLT THAT RUNS THROUGH
THE
REAR ISOLASTIC, AND ALSO LOOSEN THE NUTS ON THE HEADSTEADY.

7. PUT A SMALL HYDRAULIC JACK, ETC., UNDER THE MIDDLE OF THE LEFT FRAME
TUBE
(WITH PADDING TO PROTECT THE FRAME) AND SLOWLY RAISE THE SIDE OF THE
FRAME
UNTIL THE LEFT FOOT OF THE CENTERSTAND JUST LEAVES THE FLOOR. AT THIS
POINT,
THE WEIGHT OF THE FRAME DOES NOT REST ON THE CENTRAL BOLT OF THE REAR
ISOLASTIC, AND YOU CAN REMOVE IT EASILY. USING A SUITABLE DRIFT (A 1/2"
SOCKET EXTENSION WORKS WELL), TAP THE BIG BOLT LOOSE, CATCHING THE
VARIOUS
METAL PARTS OF THE ISOLASTIC THAT FALL FREE WHEN IT'S OUT. (BY THE WAY,
USING
A HYDRAULIC JACK THIS WAY IS ALSO USEFUL FOR GETTING THE BOLT BACK IN
WHEN
YOU'RE DONE, AND YOU CAN LOOK THROUGH THE HOLE WITH A FLASHLIGHT AND MOVE
THE
FRAME UNTIL THE PARTS ARE EXACTLY ALIGNED).

8. LOWER THE HYDRAULIC JACK. NOW THE FRAME IS HANGING ON THE POWERTRAIN
BY
THE FRONT AND TOP ISOLASTICS, AND THE TOP ISOLASTICS SHOW IT BY TWISTING
SLIGHTLY UNDER THE WEIGHT. LIFT THE REAR WHEEL (WITH A 2X4", BRICK,
ETC.)
UNTIL THE TOP ISOLASTICS ARE NO LONGER TWISTED. NOW, REMOVE THE SIDE
PLATES
OF THE TOP ISOLASTICS. (YOU DO NOT HAVE TO REMOVE THE ENGINE STEADY FROM
THE
TOP OF THE ENGINE).

9. THE POWERTRAIN IS NOW RESTING ON THE FLOOR, HELD UP THE CENTERSTAND,
BUT
IT'S ATTACHED TO THE REST OF THE BIKE ONLY BY THE FRONT ISOLASTIC. NOW,
PUT
MORE STUFF UNDER THE REAR WHEEL TO RAISE THE FRAME UNTIL THE CENTERSTAND
ALMOST COMES OFF THE FLOOR.

10. AT THIS POINT, THE FRAME TUBES ARE OUT OF THE WAY AND THE REAR
ISOLASTIC
IS COMPLETELY EXPOSED ON BOTH SIDES FOR REBUILDING.

THE "OPTIONAL" STEPS: IF YOU DIDN'T REMOVE THE PRIMARY, THE ISOLASTIC IS
COMPLETELY EXPOSED ONLY ON THE RIGHT SIDE, AND YOU WILL NEED SOME KIND OF
HOOK TO PULL THE RUBBER PARTS OUT. IF YOU DIDN'T REMOVE THE HORN, THE
FRAME
TUBES WILL BE PARTLY OUT OF THE WAY BUT NOT ENTIRELY. I RECOMMEND TAKING
OFF
BOTH OF THESE ITEMS IF YOU'RE REMOVING THE ORIGINAL ISOLASTIC RUBBER
PARTS,
BECAUSE IF THEY'RE TRULY STUCK IN THERE, IT'S A %$#@ OF A JOB TO GET THEM
OUT. ON THE OTHER HAND, CONSIDERING HOW AWFUL A JOB IT IS TO REMOVE THE
HORN, YOU MAY WANT TO TRY THIS FIRST WITH THE HORN IN PLACE AND REMOVE IT
ONLY AS A LAST RESORT. (BY THE WAY, IF YOU POUND ON THE CENTRAL RUBBER
WITH
AN ORDINARY DRIFT TO GET IT OUT, THE RUBBER ABSORBS THE SHOCK OF THE
HAMMER
BLOWS BEFORE THEY GET TRANSMITTED TO THE EDGES. THE BEST WAY IS TO POUND
ON
THE EDGES OF THE RUBBER BY USING A VERY LARGE SOCKET ON AN EXTENSION AS
YOUR
DRIFT).

REMOVING THE HORN: AS ANYONE KNOWS WHO HAS TRIED IT, THIS IS ONE OF THE
ULTIMATE BASTARD JOBS ON THE BIKE. YOU CAN DO IT WITH THE REAR WHEEL IN
PLACE BY UNBOLTING JUST THE FRONT PART OF THE REAR FENDER (TWO BOLTS NEAR
THE
TOP, TWO NUTS ON STUDS NEAR THE BOTTOM), AND FLEXING THE FENDER ENOUGH TO
"POP" IT OFF THE STUDS AND MOVE IT DOWN. THESE STUDS TURN OUT TO BE THE
BOLTS THAT HOLD THE HORN MOUNT, WHICH YOU REMOVE (TEACHING CHILDREN IN
THE
AREA SEVERAL NEW WORDS IN THE PROCESS). FINALLY, YOU CAN SQUEEZE THE
HORN
OUT OF THE SPACE BETWEEN THE FRAME AND THE FENDER -- MOVING THE REAR AXLE
AS
FAR BACK AS YOU CAN WILL

Not much anyone could add to Johns super comprehensive work list so heres a few photos to show how far forward you need to get the engine and what access you get. This is a 1970 Roadster. Not everything that you see dissasembled was to change the isolastics.