BSA B33 - Technical Specifications and Options; Sparking Plug and Oil Recommendations; Exhaust System and Gearbox Options

Sparking
Plug,
For
normal
road use,
or for fast
touring,
thi
mosr
suitable
sparking
plug
is tbe CtampioD
dodel
NA8,
For
the intermediate
compression
ratios Champion
model
NA10 or
even
the NA12
should be
used, the
latter
for rca1ly
high
duty work.
When
using alcohol
fuel with
the
highest
compression
piston,
a Champioo
model
NA14
plug
will
be
nec€ssary.
The ChampioD
NA14
is €ssential
when
racing
on
petrol
ol
petrol/benzole.
IMPORTANI.-For
warming
up with
dope use
the
Champion
LllS,
as
a long leach
plug
witå
protruding
points
will
foul the
pistotr'
Oil
Recommendrtions.
The
oil taodmendations
ats
given
itr
the chart
on
page
36 are
suitable for
most
purposes,
but
for
ulha
high speeds
a
castor base
oil may be
prefefied.
For
this
purpose
the ruoing
grades
of oil
supplied by the
6rms tabulated
in the
lubrication
chart are
suitable.
It must
always
be bome
in mind
that castor
base oil
wil not mix
with
minenl
oil, and
if a change
of lubdcant
is made.
care
must be
taken
to ensure
that the entiæ
system
is thoroughly
cleaned out,
as otherwise
a formation
of heayy
sludge
may
rcsult with
consequent
damage to
the
engine.
Exhaust
System.
Unless
rhe
purchaset
orders
a speciai
exhaust
system
to suit his
requilements
the Gold
Stals
are fitted
as s@ndard
with
a
nolmal exhaust
pipo
and
silencer,
making
them suitable
for ordinaly
road work.
For
iaciog
events wherc
silencers
are
not enforced,
these
will
naturally
be discarded
and
an exhaust
pipe
of suitable
leneth,
with or
without
megaphone,
will bo
emDloved.
Exlension
tailpipes
are
fitted
in
some
cases as
rhe
le;gh
of a straight
lhrough
pipe
is delermined
partly
Dv theenaine Derformance
as influenced
by
lhe aclual cams
usea.
ana
parity
Uy
rtre
tlpe ofevent
in which
the machhe
is to oartiaiDate.
Thedder
will,
therefore, be
uelJ advised
to exoeriment on
his o$T
machine
unlil he
6nds the
most
suitable
length of
pipe
to
suit his
rcquilemerlts.
As a
guide
see Table fV.
It should
be bome
in mind
that a
rcduction
in
lensth
will increase
the
maximum
speed at
the expetse
of a
sl ightly
reduced
pe
rformance
low
dowr. and
conversely
in
the case
of a
pipe
of
8leater
lerrgth.
Gearbox.
For_foad-racing
the
gear
change
mechanism
can De supplted
to operate
in
tbe re\erse
direction.
Maximum
Safe EDgine
Speed.
Tbe maximum
sDeed
should
nol
be allowed
ro
exceed
6,800
r.p.m.
on the
832
and
9,1q- l.p.ttr.
on the
Bl4
unless
orherwise
specjfied
in
the
iadividual
Certificate
of
perfolmance
issued
with
the
machine-
Rev.
CounteB.
These
are
available
for
Gold
Star engines.
The conve$ion
entails
the
fittitrg
of a
modified
tLrine
cover.
Tlres,
Sizes
ro ind;vidual
rcquifements.
Fronr
Tyre:_
3.00-2-1,
or
3.00-t9.
Rear lyre:
3.25-19,3.5b_
t9
and
4.00-19.
Ilandl€bar
Levers
(Front
Brake
and
Clutch).
On racing
machines
an
additioDal
knurled
finger
adjusrer is
provideå
at tne
nanolebal
lever.
Front
Brake.
For Scrambles
a 7in.
dia.
brake is
used.
(For
adjustment
see
page
32.),
Other
models
are fitted
with
an
8
in.
dia.
brake,
This is
described
oD
page
60.
TAILE
IV
EXHAUST
COMBINATIONS
Exhaust
System
ii
834
Gold
Star
Plain
Pipe extensiotr
lengtb
measuted
on
outside
of
Clubmatr's..
Pipe
for use
wirh
Mega-
phone
oength,
measured
on
outside ol
bend)
Megaphone,
length
Megaphone,
major
dia.
.,
Exhaust
Pipe
dia.
(TouriDg)
Exlraust Pipe
dia.
(Scrambles)
Erhaust Pipe
dia.
(Clubman's)
53
ins.
42 ins.
35
ins.
l4
ins,
3
iå
ins.
(inverse
cone
1l
ins.
rå
rns.
l* ins.
Gerr
Rados, Four
ranges
of
g€arbox
ratios
arc
availablc
for
lhcse
models,
as
follows:
53 ins.
43 ins.
35 ins.
loi ins
3
iå
ins
lå lns
ti rns
tns.
I
rns.
rns.
lns.
ins.
ina.
56
57
l