Sunbeam S7 questions

Anyone ever had one of these? I've always like the looks. but have been put
off by criticisms of the handling and the worm drive (and the cost!). Any
advantage to buying one in the USA and bringing it back?
Kes.

 

I've often wondered about that worm drive. Like, a worm drive is a
one-way thing: you can drive the pinion with the worm, but not vice
versa. Think of the machine heads on a guitar - don't exactly unwind
under string tension, do they? If you did something foolish like
finding a false neutral, or pulling the clutch lever in, presumably the
back end would lock up, as the shaft wasn't being driven. Possibly
there's a freewheel of some sort.

--
Platypus
VN800 Drifter, R80RT
DIAABTCOD#2 GPOTHUF#19
BOTAFOS#6 BOTAFOT#89
BOB#1 SBS#35 ANORAK#18 TWA#15

 

That final drive is a terrible weakness (1) and there is no getting away
from it but otherwise it's a lovely SOB.

(1) if not using hard or high miles doesn't matter?

 

I've just dug out an article[1] on the S7/S8, which reckons that the can
of worm would become uncomfortably warm in everyday use, and would wear
out completely in a few hundred miles on the sports model.

[1]Gurt British Motor Cycles of The Fifties by Bob Currie, twa squids
from the local cheap bookshop a couple of years ago.

--
Platypus
VN800 Drifter, R80RT
DIAABTCOD#2 GPOTHUF#19
BOTAFOS#6 BOTAFOT#89
BOB#1 SBS#35 ANORAK#18 TWA#15

 

I believe it does have a car-type freewheel, I've also read that there's no
engine braking (to reduce wear on the worm drive teeth) so it must
disconnect when you throttle off I suppose. I think that's why the bike
goes all over the place when you blip the throttle. Anyway, it does look
nice.

 

It's quite possible to make a worm drive that works on over-run and many car
manufacturers have done it. Probably the ratio involved has something to do
the reversibility. They do tend to need special oils though, you can't
chuck in any old gear oil and expect to get away with it. Peugeot, who only
gave up worm drive on cars in about 1965, used to specify a castor base oil
made by Mobil, though probably old fashioned thick Castrol R would have
worked OK.

Ron Robinson

 

It it a true worm drive, though - or just a short one? I'm thinking a
short one might be able to over-run. Perhaps it's a hypoid bevel and
mis-called worm.

--

Dave

GS 850 x2 / SE 6a
SbS#6? DIAABTCOD#16 APOSTLE#16? FUB#3
FUB KotL OSOS#12? UKRMMA#19

 

I know nothing, but a pal had them and swore about the brakes a lot.