the primary case (or file or even clip it away with tinsnips to about half the radial thickness).
J.H.: I believe layshaft bail bearing failures arc more frequent when:-
1. The 22T gearbox sprocket is used as on 850s and
2. Every failure I have seen has been a Portuguese SKF bearing.
In Birmingham they insisted on Hoffmann 117 bearings bring used here but, of
course. as
Tim rightly
points out we did not have so much power. Even so, the Hoffmann bearing-now RHP---would probably
stand up better to present 850 conditions.
It seems to me very unfortunate that they did not change Commando gear ratios by using alternative
engine sprockets, because with a larger engine sprocket and retaining say, a 19T on the gearbox (as was
standard on all Norton Nortons from Model 50 to Atlas and Manx) the speed of the box would be
increased without such a heavy journal load on -the bearings and tooth loading on the pinions
themselves. > >
Any rider of an 850 Commando in particular, but 750 also, should stop immediately if he feels the
slightest sudden roughness in the intermediate gears especially if the kickstarter flies back because this is
a sure indication of layshaft bearing failure.
As well as the sprockets listed (19T to 24T) there are 17T for Matchless and 16T for sidecar scrambling-
available from your local friendly. This o-rings us to the kickstart pawl. These break. Only sometimes and
much less often on recent machines than on 1970 and 1971 bikes. Recent pawls are cast from steel (by
lost wax process, by the way) and have an M an the side: they are much more reliable. If the pawl does
break, the side bits of the T shape wedge in the bottom gear pinion and the kickstart is carried down on
its own and can then stay down-waiting for you to go round a right hander. If the kickstart flies up again
there is no reason why it shouldn't happen again-or the bits can get between any of the other gears-rather
to the detriment of the abaft straightness and freedom from broken teeth and broken cases. So, for
whatever reason the kickstart plays up-don't just carry on. You can get the covers off at the roadside with
the too! kit and a large brink--the long black spanner is 15/16in at the large end-not exactly 1in Whitworth,
but only 0.0175in too big, and in these circumstances no one will argue about 17 thou. That's to got the
mainshaft nut off. Of course, you can got -the clutch operating housing unscrewed with the brick and a
tyre fever. Brutal, but inevitable there's no special tool unless you make your own special tube using a
piece of 1 }in LD. tube and filing as per diag 1. To use the tube you'll have to remove the roller and
operating lever. I his part must be screwed up with the clot in the housing in line with the cable hole in the
cover, so mark the position before unscrewing it. If it is not lined up correctly the clutch operation
becomes stiff because the cable has to go round too many corners.
Diagram 1.
Another cause of stiff clutch action is the operating lever that fits in the slot. The outer Profile of this bears
on the roller in the end of the slot and if profile is notchy so is the clutch action. You can alter the profile
with a grinding wheel (or by trying another lever) so that the lift is gradual and
16