Do you remember the good old days when Classic and
Motorcycle Mechanics used to do those very useful stage by stage strip down
articles of Villiers engines? As a learner at this game I have found them very
useful when exploring the innards of Villiers engines, but unfortunately they
have abandoned this sector of motorcycling activities to concentrate on
Japanese machines. As the Club which represents this need I thought that it
would be good to have our own versions and decided that I would try my hand at an equivalent article
for the Villiers 1F which is fitted to my James Comet.
The problem which prompted this strip down was a
degree of clutch drag which meant that when I engaged first gear there was
always a nasty clangcrunch as the dogs meshed together. I was worried that
frequent use was gradually ruining the gears so resolved to check that the
clutch was sound and properly set up, but on the 1F the clutch is not as easy
to get at as it is on the ‘D’ and ‘E’ series engines. The 1F has only two main
castings, the left hand incorporates the crankcase and gear box, and the right
hand acts as the primary chain case and carries the kickstart mechanism and the
armature plate. The clutch assembly runs between these two so they have to be
separated to examine the clutch.
On a bike as simple as this it is easy to get the
engine out of the frame. There are only three mounting bolts and the other
connections are easily separated and the engine can then be lifted out onto the
bench. To hold it steady while you grapple with the dismantling I recommend
bolting on a piece of plate (I used 5mm drilled to take an engine mounting
bolt) which can then be clamped in the
vice
Remove the flywheel cover plate and then the flywheel.
If you have a Villiers Hammertite spanner you can just hold the flywheel while
you give the spanner a smart rap with a copper hammer. The nut then unscrews a
bit and tightens when it will need a bit more force to undo as the nut pulls it
off the taper. Once you have the flywheel off put it in a plastic bag otherwise
the magnets will attract all the metallic rubbish which floats around the work
area. Also remove the kickstart cover.
Next remove the armature plate which carries the coils
and is held onto the clutch case by four small slot head screws. These are
often difficult to shift and will need a screwdriver that is really clean and
neatly squared off to give a good fit in the slots. Having removed these the
armature plate comes easily off its boss on the clutch case. At this stage also
remove the kick start ratchet which is held on by a circlip.
Now remove the drain plug in the bottom of the clutch
case and collect any dirty oil. You can then undo the clutch cover fixings (2
nuts on studs, 2 slot head screws, 2 hex head screws). In my copy of the
Villiers 1F manual there is an illustration of an elaborate extractor (ST 148) for withdrawing the clutch case off
the clutch shaft and crank shaft. My engine is a bit worn so there are no tight
fits and with a judicious tap with a mallet the two halves of the engine came
apart easily to reveal the primary drive.
To remove the clutch assembly it is necessary to
remove the engine sprocket. You will need to devise a way of locking the
sprocket. Villiers supplied a special tool for this that dropped over the
sprocket and was bolted to the gear case but we can get by with a suitable
piece of wood jammed against the chain. Pull the engine sprocket off its keyway
at the same time as the clutch assembly is withdrawn. Sprocket, clutch shaft
and chain can be removed as a unit. The clutch assembly can then be examined.
You will see that I keep a collection of ice cream tubs which are ideal for
sorting parts as they are taken off, keeping different sub-assemblies separate.
Holding the clutch shaft in the vice enables you to
remove the clutch nut lock washer, clutch nut, clutch spring and its bush,
before removing the clutch plates. The clutch spring is under compression so as
the nut is undone it will come off with a bit of a jump. As you remove the
plates watch out for the positioning of the cotter that releases the clutch
plate pressure.
You can then examine the clutch plates for
deterioration, buckled plates, worn corks, gummy residues and so on. Everything
on mine seemed to be acceptable so I commenced re-assembly.
With the clutch shaft still in the vice I put the
plates back in reverse order. First the outer plate with holes goes next to the
circlip that retains the gear wheel. Then the tanged plate,
dished centre plate with the dished side towards the
tanged plate. The cotter should then be fitted into the slot in the shaft, then
the chain wheel and finally the outer plate. Then you have the problem of
assembling the clutch spring nut against the pressure of the spring. I found
that a piece of tube placed over the clutch shaft after the nut was in place
enabled me to squeeze up the spring in the vice to the point where the nut was
about to engage the thread on the shaft. A careful turn of the spanner got the
nut going on its thread and then finally fully tightened.
The final position of the nut is crucial because the
clutch assembly is sandwiched between bearings which are housed in the two main
castings. Villiers provided a gap gauge to dealers with a max of 3.696” (93.88 mm) and a min of 3.676” (93.37
mm)
If the nut is
overtightened the dimension will be too small and when the clutch is operated
the whole assembly will move rather
than compressing the spring. To get a clearer view of
this I cut an old casting in half to see the action
I have two boxes of old 1F bits (cranks, clutch
assemblies, castings etc), and if anybody wants any let me know.
Once this stage is over it remains to re-assemble the
rest of the parts. There are only two points of special note. Firstly I always
add a drop of Loctite when re-fitting the armature plate fixing screws.
Secondly because the fly wheel is not keyed it is necessary to retime the
magneto, but this is easy by getting the timing marks in line when the piston
is at top dead centre.
Finally after all this I put the engine back into the
bike and started the engine and checked the clutch. Clangcrunch! Just the same
as before! I put the bike in the shed
and sulked away to do something else. After a few days when I had cooled off I
started to wonder what the problem was. It occurred to me that the clutch
operating arm on the engine was not getting its full movement. A quick check
showed that it was fully operating after 15mm of movement. For some reason the
clutch lever on the handlebar was only giving 11 mm so the problem was that
there was insufficient movement. Why was this ? By comparing the two levers,
clutch and front brake I found that the
lever has at some time been bent slightly, and it was coming up against the
handle bar rubber too early. These levers are only a spindly bit of brass and a
careful bit of bending away from the handlebar pretty well solved the problem.
It’s called learning the hard way.
John
Hawthorn.
Reprinted
by popular request
TECHNICAL DATA FOR VILLIERS ENGINES
MODEL CC BORE x STROKE PLUG TIMING PETROIL
OIL
MkIV 269 70
70 A6 3/10
16:1 0 /0
MkV111C 147 55
62 A6 1/4
16:1 0 /0
MkX11C 148 53
67 A6 1/4
16:1 0 /0
1E 196 61
67 A6 7/32
16:1 0 /0
3E 196 59
72 A6 3/8
16:1 0 /0
7A-10A 247 67
70 A6 5/16
16:1 0 /0
14A 247 63
80 A6 3/8
16:1 0 /0
16A 247 67
70 A6 5/16
16:1 0 /0
17A-18A 247 67
70 A6 7/16
16:1 0 /0
6B-10B 342 79 70 A6
5/16 16:1 0
/0
14B 346 70
90 A6 3/8
16:1 0 /0
Midget 98 50
50 A6 11/64
16:1 0 /140
Junior 98 50
50 B6HS 5/16
16:1 0 /140
JDL 98 50 50 A6
1/4 20:1 0
/140
9D 122 B7HS 5/16
16:1 140/140
1F-2F 98 47
57 B7HS 1/8
16:1 0 /140
10D 122 50
62 B7HS 5/32
16:1 140/140
6E 197 59
72 B7HS 5/32
16:1 140/140
11D-12D 122 50
62 B7HS 5/32
20:1 140/140
7E-8E 197 59
72 B7HS 5/32
20:1 140/140
4F-6F 98 47
57 B7HS 1/8
20:1 0 /140
1H 225
63 72 B7HS
5/32 20:1 20 /30
3K 50 40
39.7 B7HS 3/32
24:1 0 /30
13D 122 50
62 B7HS 5/32
20:1 140/140
29C-30C 147 55
62 B7HS 5/32
20:1 140/140
8E 197
59 72 B7HS
5/32 20:1 140/140
9E-11E 197 59
72 B7HS 11/64
20:1 20 /30
2L 173 59
63.5 B7HS 11/64
20:1 20 /30
31C 148 57
58 B7HS 11/64
20:1 20 /30
31/32/35A 246 66 72
B7HS 11/64 20:1
20 /30
33/34/36A 246 66 72
B8HS 1/8 24:1(R)
20 /30
2T 249 50
63.5 B7HS 5/32
20:1 20 /30
3T 324 57
63.5 B7HS 3/16
20:1 20 /30
4T 249
50 63.5 B7HS
5/32 20:1 5
/30
27B 353 A7 3/16
16:1 0 /0
2H 246 66
72 B7HS 11/64
20:1 20 /30
AMC 15T 149 55
62.7 B6ES 3/32
24:1 30 /30
AMC 10T 175 B6ES 24:1 50 /50
AMC 20T 199 59
73 B6ES 24:1 50 /50
AMC 25T 249 66
72 B6ES 1/4
24:1 50 /50
NOTES:- Bore/stroke in Millimetres.
Plugs quoted are NGK ref
Timing is in Inches
before Top Dead Centre
Oils quoted are primary
chaincase/gearbox viscosity
(where 0 is shown then the engine does
not have a fitted
gearbox and lubrication depends on box
fitted and the
primary chain is either unlubricated
or by gearbox oil)
We realise that this list is not by any means complete and that
quite a few engines have been left out whereas AMC are included.
At one of the occasional meetings of the Essex section, at the start of July, we were discussing various matters concerning Villiers engines – as you do, when I mentioned that some of the things which had been generally thought, and which tended to get carried on from publication to publication, were perhaps not necessarily so and cited the case of the 197cc 9E and 10E engines and the general view that the 10E had an upright cylinder position, while the 9E sloped forwards. Like the others, I also used to take this at its face value (after all my 10E powered Francis Barnett had an upright cylinder)
It was some years ago, when on the BTSC stand at the
Snetterton Festival of a Thousand Bikes event, that I met someone who said that
he had done a lot of work on tuning Villiers engines, written a couple of books
on them and (I think) also worked at the factory at some time. He told me that it was a load of nonsense
and that the two engines were mechanically the same. I noted what he said (but not, unfortunately, his name) at the
time, but never actually got around to checking it out.
As the others were still of the opinion that the two
engines were different we got the parts list books out for the two engines and
sure enough the two engines had the same crankcase part numbers. Just to make
sure, the following day I went through the lot and the only bits that were
different were the cosmetically different left and right side outer cases,
which were different to suit Francis Barnett and James, who it seemed did not
want either the Villiers motif on the left, or the characteristic ribbing on
either side. The only mechanical difference was the inlet stub, which kept the
carburettor mounting straight and showed that the 9E only had a sloping
cylinder because the whole engine was canted forward and when using the 10E
inlet stub, would be mechanically identical to the 10E..
In the past, I
too had been guilty of perpetuating the story that James and Francis
Barnett did not change to the 9E when it first came out, because they wanted an
upright cylinder to their engine, for its better looks in their bikes. However,
being that the 10E is the same engine it poses some intriguing questions that I
had not previously thought about. Mainly, why did the AMC marques of James and
Francis Barnett continue to use the, by then, dated looking 8E and thereby making their products rather
“old fashioned” looking when compared with their competitors?
Surely, it wasn’t just a case of Villiers not
supplying an inlet stub for an upright cylinder! I find that difficult to
believe, unless they were hoping to force the AMC organisation to continue
buying up their 8E units, in the belief that the 9E could only be mounted with
a sloping cylinder, thereby conveniently clearing their obsolete stock. Or did
they come to an arrangement to continue to provide 8E units to AMC at a “knock
down price”, which was too tempting for the AMC accountants to resist.
Or could it be that James and Francis Barnett did not
want to change the engine mountings on their frames to suit a new Villiers
engine because they were expecting an early delivery of the 200cc versions of
their own engine, to run alongside the 250cc 25T which was already in
production, but whch in fact never turned up till 1960.
Whatever the reason (and I would love to know the
reason from someone close to the decision making) by 1958 even AMC decided they
could no longer continue with the outdated 8E and had to change anyway. So why
the 10E designation for the new engine? Was it just to denote the cosmetic
changes presumably demanded by their large AMC customer and avoid any confusion
between the James and Francis Barnett spare parts books and that of Villiers
themselves? Or was there another more intriguing reason? I would be very interested to know.
Colin Atkinson