Is a Sunbeam S8 capable of cruising at 57mph?

[antoni]

...and would I be able to get spares and maintain it?

I've ridden a G3LS for 10,000 miles over 10 years.

[iansoady]

For a while......

Although the fake Sunbeams are very popular with those with a hipster leaning they did have a number of design flaws including the worm drive back axle. If I was looking for a 500 twin I'd go for an A7 unless you really want shaft drive in which case a BMW might suit you. But your Matchless would probably be nearly as fast......

Spares are available for the S7 / S8 from Stewart Engineering.

[Rex]

As I understand it the old "rear drive problems"  ended when a) the bikes stopped being merely old nails and started to be maintained properly, and b) when better oils became available.

A charming old bike which always attracts people ready to chat.  My mate's bike does more than 57mph but like so many 65 year olds, it's cruelty to expect longevity if you anticipate doing those speeds continuously.

[mini-me]

I love these posts about whether this or that  50 yr old bike will cruise at 80mph all day or some such nonsense.

Have these people never heard of  Japanese bikes, or even Triumph?

[antoni]

Mr. Me,

Do you love these posts or do you not like them?

57 mph is a very important speed to be able to maintain if you find yourself needing to use motorways or A-roads. Informed opinions on a marque and model are what this forum is about.

Moving onto the Sunbeams' worm drive, would modern lubricants designed for 'modern' hypoid drive differentials be appropriate for an old drive using old metal alloys?

For example it is necessary to use safe lubricants in my 1960 Regal MkV's transmission. There are unsafe ones.

[TGR90B]

Judge for yourself on a bike with a tested top speed of 83mph in 1950. 80mph in third BTW.

[mini-me]

#1 don't ride on motorways,they are no place for old bikes, from the point of view of safety and other users if nothing else.
#2 On A roads, but never dual carrigeways, where I often ride bikes older that an S8, I do not attempt to keep up with or in front of other traffic.

Informed opinions on a marque and model are what this forum is about.

Thats what you got, I've been 55 years on british bikes,seen the roads change beyond all comprehension, as well as deteriorating standards of driver behaviour.

I was taught by BSM  to drive a car in the Tottenham Court Road in the mid 60s, try that now.

The smallest cars on the road today are faster and better brakes, acceleration etc than your S8, just enjoy the ride and let the fools rush past.

57mph,such a definative  figure, not 55? or 58? your speedo won't be that accurate.

Although the fake Sunbeams are very popular with those with a hipster leaning

also required a beard, a man bun,silly haircut, face ironmongery, and an inability to order  a plain cup of coffee,.

oh my god I need a skinny latte mocha frapp now........ BARISTA!!!!

[antoni]

Thanks for the replies. I tried to be concise in my original post but it seems more detail is needed. I love riding at 30-40 mph on backroads. That's what 90% of my riding is.

There are events which I would like to be able to ride to instead of driving to. So that's - say - 3 round trips of 120 miles per year tops.

My Matchless is only borderline happy holding 57 mph and thereby avoiding the need for speed-limited 56mph lorries overtaking me leaving 12 inches of clearance between me and them.

My rebuilt Smiths Chronometric is the most accurate speedo I've ever used. That's why the ploice BMs had them installed in the 80s

Can a bike which achieved 83mph (presumably briefly) in 1950 steadily hold me ahead of the angry lorries, without overheating its rear cylinder, or overstressing its worm drive or any other of its parts?

I don't know the answer to those questions but I notice that the Sunbeams might be had for less eyewatering sums than the usual suspects.

What is a fake Sunbeam? I'm baffled!

[mini-me]

I'd suggest when one of theose HGvs overtake, hang back, you can't be in such a hurry?

Having been a mechanic for the Met and City police I think I can speak with some knowledge of their speedo practice; they were regularly checked and calibrated by a specialist police dept,run by a copper.

I was also there when the City Police took delivery of the first BMW bikes by any Police force[they were horrible bikes] and I| have the certificates from BMW to qualify me to decide what rubbish they were. I once owned an ex police RT  which was the most unreliable bike I have ever owned apart from an XZ Yamaha, so I'm not impressed by BMW worship.

I forget at what intervals but often a defence lawyer would be sure to ask when calibration was last carried out.

Yes chronos are accurate, but not as accurate as you want/believe them to be, do the numbers on the dial tally with orginal spec?

A fake Sunbeam is one made by BSA, not by Marstons in Wolverhampton, or even AMC pre war.

As you are familiar with AMC singles why not look for a 500?  that will fill your want.


Police motorcycles are nothing special apart from a few police equipment mods, despite the bollox/wishful thinking I often read from the fanciful.

The most reliable modern bike I owned was the often mocked CX500 Honda, nearly 100.k on the clock when I sold it, going up in value, far better than an S8.

[antoni]

Thank you for your contribution to this thread Mr. Me.

[mini-me]

No trouble,I said all I have to say, except that you are looking for a unicorn.

[john.k]

Hypoid and extreme pressure (EP) additives DESTROY  bronze gears in worm drives................you need some kind of high spec industrial worm gear lube............The old worm drive iubes contained around 20-30% castor oil.........Pre 1950 many big trucks had bronze worm drives,and worm oils were freely available..........one I remember is Dentax W which we used in the worm diffs of the Coles 30 ton cranes.

[Rex]

http://www.stewartengineering.co.uk/viewPart.asp?id=1056

From the Sunbeam experts.

[john.k]

To be passing any speed limited trucks in Aus,you ll be needing a Vincent Rapide.....speed limited to 104k,they cruise at 120k,and pass cars a dozen at a time.........there are plenty of the S8 Sunbeams for sale here ,for not much money,because they cant hack it on the hi way.

[Mark M]

I have ridden thousands of miles with a best friend on a Sunbeam S7. The answer to your question is yes. His self imposed top speed is just under 60mph, this is to keep oil consumption at a reasonable level and just general mechanical sympathy for an old lady! The S8 is lighter so should manage 57 easily. My pal has had 'Beams for over 40 years and was well connected to the original Stewarts of Putney. The rear drive "problem" is largely a myth created by poor/lack of maintenance and the wrong oil. Modern hypoids are the answer. Motorway work is not the ideal place for a 50s bike but my experience is that truck drivers are usually very sympathetic to bikes, a truck driving friend tells me many drivers ride themselves as an antidote to being stuck behind the wheel all day!
REgards, Mark