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During the years I have the WD16H, and while making this website and
answering people on various items, I found that a number of parts are not
given in the spare parts lists or described in the Maintenance &
Instruction Manuals that I have. The consistency with which they are not given is puzzeling. Nobody
bothered to mention it, or Norton was not interested in correcting it.
Other parts are prone to failure but their failure is not
always obvious.
The engineering of the bike is lovely crude. Some of its additions
have (in my opinion) a token value only.
I hope my experiences can be of help. I expect this to become a small list in the end.
It is not always to be taken as advice. It is always your own decision and
responsibility if you follow what I did/do.
MYSTERIOUS PARTS
Crankcase breather valve.
To alleviate the pressure differences which develop in the crankcase when
the piston is going up and down, a pressure relieve system is usually
utilized. On the 16H and Big 4 engine, this consists of a a pressure relieve valve
using a steel ball to close the case when the piston goes up, and vents
when the piston goes down. (There is another channel drilled
in the crankcase LH side below the main axle, it will breathe also, but I
am not sure what the exact function is). The crankcase breather tube is visible behind the top end of
the primary chain case and pointed in the direction of the rear chain on
which it spits any excess of oil. This copper breather tube, steel ball
valve and the brass nipples are not very obvious in the spare parts list.
It is listed under Transmission as "Crankcase breather, complete with
Pipe" part no. 9531. It would be more appropriate in the Engine
section!
The Maintenance and Instruction manuals do refer to a valve,
without further description of the configuration.
I did not know a "ball" valve was supposed to be there until I opened
an engine which I obtained lateron, on which it was mounted. Apparently I
just didn't
read the M&I manual properly before, but if I did I wouldn't know what
it looked like!
I have found more engines without the valve installed. As a slight
underpressure in de crankcase, when the piston goes up, is beneficial in
sucking some oil through the cylinder backwall channel (lubricating the
rear of the piston skirt). I think it should be present and working.
Bottom view crankcase breather
valve
Top view crankcase breather valve
Felt and leather washers
Many bikes have lost their felt and leather washers over the years.
Many people don't even know there should be any at all. The M&I manual
does sometimes mention them, but they are relatively mysterious.
I made them all and think they are usefull in keeping muck out and
grease in. Between the primary chaincase and the engine crankcase a
leather washer is used. Between the primary chaincase and the gearbox a
felt washers is used. I added a felt washer between the magneto and the
timing chain case. Felt washers were further used for : clutch nut, gear
change pawl carrier, wheel hub bearings (both sides), inside primary
chaincase between footrest tube and outer casing, and sheets of packing
felt between the top frame tube and the petrol tank on "later"
bikes. ("Early" bikes used rubber sheets (See pictures of most
original WD16H).
Gearbox main axle dished spring washer
The exploded view drawings of the gearbox in the Maintenance and
Instrucion manual as well as various books, show a dished steel spring
washer at the end of the main axle. I personally have never found such a
washer in a gearbox, and wonder if they were actually used on all boxes,
or only the later ones. Its not given in the spare parts list of either
old or newer contracts or postwar civilian lists. The dimensions are I.D.
5/8", O.D. 1 7/16", steel thickness 1/64" and dished height 1/16" as
measured from a used washer by Lex Schmidt.
Magdyno platform variations
When restoring a military 16 H or Big 4 from scratch, one
unfortunate finding could be that the timing chain as dictated by
the magdyno sprocket does not run in line with the driving timing
sprocket.
When using the wrong platform, there is no gap between the rear of
the timing chain cover and the Magdyno. When using the correct
platform there should be a clear gap between those parts. I cannot
give an exact measurement for the gap as there are many variations
but some measured results are around 3/16" (4,7) mm. To prevent
muck to enter the timing chest through this gap I have made a
fitting felt washer mount between the magdyno and the timing chain
with such dimension that it does not interfere with the rotating
magdyno shaft and is not to obtrusive when looking at it from the
outside.
The in-line deviation will not happen (on military bikes) when
using the cast iron version as made during the war (casting number
12311), but it can happen when applying the aluminium version as
used before and after the war. The correct aluminium version has a
casting number 11699 on it. One incorrect alu version has a casting
number 13814 on it, there may be more alu casting numbers.
The civilian Norton part number changed from 3711 (prewar military
and civilian prior to 1938) to 3711A for the cast iron version to
A2/117 in 1946 and 1947.
The 1938/39 civilian Norton part number was 8918, but its not clear
yet if they deviated in dimensions or casting number and whether
they are identical to the prewar 1938/1938 civilian version.
There has also been a part number C2/117 but its not known (at this
moment of writing) in what sense it differs from A2/117 or 3711(A).
The number 13814 was found on a platform labelled C2/117.
NOT SO VISIBLE FAILURES (AND SPARES)
Main Gear Wheel Sleeve Bearing Roller Retainer Washer.
Pictures of the "exploded view" gearbox show that the rollers in
the main gear wheel are neatly housed. What it does not show is that the
rollers are closed into the main gear wheel by a steel washer, against
which the bronze clutch thrust washer rotates when activating the clutch.
Look at the picture given in the
gearbox and transmission
page where I added the washer for clarity.
This hardened steel washer has the tendency to fracture. Two of the 3
gearboxes I have showed this to be the case. The washer is given in the
spare parts lists (all) under no 3598 (Main Gear Wheel Sleeve Bearing
Roller Retainer Washer). I have however not been able to find
original replacements for them, and had them made from a cold work tool
steel (AISI D2 or UNS T30402) and hardened to 59 Rc. Remains of the
original were measured to be 60 Rc so I think I am close enough.
Loosening clutch nuts
On some bikes, you see an additional disc in the large depression
produced in the primary chain case to house the clutch. This is usually
the result of adjustment of the clutch disengagement while actually the
clutch nut has come loose.
So if you ever have the urge to adjust the clutch disengagement stroke, first check the central
nut on the clutch. Despite the spring washer behind it, it loosens on
occassion.
OIL AND GREASE STUFF (See alo the
running a 16H or Big 4 page)
Oil return lines.
Anybody not having used his bike for some time will have experienced the
blubbering noises and heavy kickstarter actuation when trying to start his
machine. I know, everybody has a perfect oilpump, but me?
The oil tank has drained itself into the engine
crankcase after finding its way past the gears of the oil pump.
My solution to the problem is adding a tap into the oil feed line.
Dangerous? only when you forget to open it before starting. If you
don't trust yourself, hang a "remove before flight" banner on
your handlebar! Modern motorcycles do it for their disk brake lock.
I have used it for 20 years now and forgot it twice. Because I regularly
check the oil tell tale after start up, the ommision shows itself
immediately. With such a "high" powered engine as the 16H, I
really don't expect a lot of additional wear on the internals. I am rather
convinced you can ride it without oil for some time if you don't revv it
up too much. OK I know it is not meant to be so!
Valve grease nipples.
One of the most amazing features on the 16H engine are its valves. There
are grease nipples on the valve guides as a token addition to subdue valve
stem wear. Initially I used to give them a squirt of high temp molybdenum
based grease. This usually resulted in a fairly sizable smoke curtain at
the beginning of a trip.
I stopped greasing them as I don't think it has any use. I am now about
15.000 miles further since I stoppped greasing and it still works. I know
I don't have the maximum compression, and I don't go faster than 50 MPH
anyhow because that is a very uncomfortable speed on a dinosaur
suspension. But what the heck, put in a new set of valves and guides and I
will ride into my old age pension!
These bikes are rugged!!!! I love it!
Latest tip I got was the use of : "(air) gun grease". This
apparently has a very high temperature resistance, and would therefore be
able to withstand the temperatures of the cylinder head. I will try to get
some and have a go at it myself. Keep you posted. I will first try to do
some temperature measurements on the barrel using a non contact gauge as used
by modellers. Then see if it is usefull.
Oil regulating grub screw on top of timing cover
An often asked question reaching me is about the setting of the grub
screw valve on top of the timing cover.
The setting of this grub screw regulates the amount of oil being fed to
the rear of the piston/cylinder.
It is not properly described in the military Maintenance and Instruction
manuals people usually use as guide.
The setting of this was done at the factory and should normally not need
to be touched. After 60 odd years however some cleaning of the insides
may be required or the workmanship of previous owners needs to be
checked.
The standard setting of this screw is one turn from the fully closed
position. (According to EM Franks in 1952).
Its difficult to say if this is still correct for all engines, but
depending on the state of the engine it may need some adjustment.
It should be adjusted such that there is a minimal amount of smoke
coming from the exhaust. As the smoke from the exhaust does not only
come from this setting, its a setting with lots of possible positions.
The standard setting is therefore the most likely correct one.
THREADS ON NUTS AND BOLTS.
Attached
list (MS Excel file) shows all nuts and bolt sizes on the Norton 16H.
Most of these are also used on the Big 4.
The list can be usefull if you are searching what taps and dies you
might need to clean up threads or recreate fasteners.
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