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.