Norton 850 Mk 1 1974, Service Notes, Page: 11 / 48

it, (A.F, stands far American Fred, by the way, a fact first mentioned in the Vincent Owners magazine.) (I thought it
stood for Awkward F----r!)
ROCKER SPINDLES: The rocker spindles are fitted with the oil flats outwards -away from the holes in the rockers
--because otherwise too much oil swamps the head. The rocker spindle locating plates always seemed to me to be a
very complicated way of avoiding a simple die casting, but there's nothing much to say about them except that they
usually weep a hit.
HEAD BOLTS AND NUTS: Nothing extraordinary, either, about these. except -- the nut holding the head dawn at
the hack. on all engines, is 3/8in x 26 tpi, but the similar nuts on the base flange of the latest 750's (those with the
breather at the back of the crankcase) are tapped 3/8in x 24 tpi (American Fred, again! ). and by the time you've
realized this, the threads have so thoroughly jammed together that the nut and the stud are both ruined. Ask your
local dealer it he stocks either . . . You will note that the size of both nuts from the outside is 1in Whitworth to add to
the confusion.
EXHAUST THREADS: The exhaust threads in the cylinder head cannot be stripped using the standard nuts and the
large service C ring-the fins on the nuts bend first. If the nuts aren't tightened enough, an pre-delivery, they will
loosen and the lock rings enable you to carry on like this so that the threads wear, and %ill subsequently strip.
To stop my exhaust rings coming undone 1 use two short pieces of steel wire bent into loops about 2in long x „in
width connected to each end of a 3in x 4 spring a-la stop light switch, This is looped over the fins of the clamp
rings, making sure it is tending to tighten them Maybe even another small loop of wire to retain the device to the rev
counter cable so if one end comes adrift the device isn't lost in the bushes!
The 850 Mk llA of Hill Nicol, Bury .St. Edmunds, The tin covers on the rear suspension ran only he an improvement
while skimming the chrome off of the disc is a personal choice.
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