Now came the cross studs there are two, one at the rear, one at the front. The normal penetrating fluid and wait procedure, was rewarded by the rear cross stud sliding out, but the front one was stubborn to the point where I thought I would have to cut it out. Without much hope I heated the stud ends in turn, hoping that heat would penetrate down the stud into the cross tunnel (above the sump). I also purchased some acetone and mixed with some transmission fluid I attempted to get some to travel (without much hope) down the frame, across the spacer, and finally into and along the tunnel all in a horizontal direction. The next day I fitted a rusty nut to each stud end and started to swing my 2lb copper hammer, after a few blows the vernier gauge registered a slight inward movement left. Not getting my hopes up I went to the left side, and welted that end repeatedly. I was rewarded with a definite movement rightwards. This back and forth continued, till I could move the stud back and forth to the inch or so that the studs would allow. Another anointment of fluids followed and the following day with a brass drift out came the stud.
The engine was balanced on two jacks, and following the normal procedures out came the engine and gearbox to the bench, now finally I could clean the engine remove the electrics, clean the gearbox and rear assembly and take all three items away for inspection
The electrics were in a terrible state so taking plenty of pictures I removed them .In all the corrosion and rust I had not so far snapped any fasteners, that run was broken on the lower small screw of the contact breaker back plate.
I now turned my attention to the last major item of the strip down, the front assembly. Initially I could not see how the wheel could be removed .It transpired that the wheel spindle A that threaded the swinging arm* B did actually pass right through the hollow spindle* C that held the internal steering stem* (not shown)and that the central hub was held by the three bolts D each side that were secured on the steering yoke* E (*My terms). Mercifully all eight bolts undid with minimum protest
R75/6 || 03/74 || 4011632 || 4011835 Model manf date from to
I was by this time getting very confused with exactly what model of BMW engine I was dealing with, a faded maintenance book that came with the bike was for a R75/5 while the date of manufacture on the V5c was 1975. Eventually I traced the engine number to the non US sequence that confirmed it was an R75/6 built in March 1974 so its the same age as my son!