Spagthorpe(R) Motorcycles

I Decided to look for some inormation on Spagthorpe(R), as I realized
I knew the name, but nothing about the company.

The first image the turned up was this jpg
http://www.spagthorpe.com/production/rottweiler.html

How terribly tragic.

They were pioneers in the develepment of new technologies including
rotarian valves, the "five-and-a-half-cylinder" engine and of course the
wonderful eight cylinder, 40 valve, 124.5cc Feral Flea.

Quote:
"There was, of course, the Spagthorpe Wrestler engine, which was a
horizontally opposed twin having no crankshaft and a single rod
connecting the two pistons. Teeth on the top and bottom of this rod
drove gears which transmitted the motions to the gearbox. The pistons
were lead weighted to provide sufficient momentum to complete the
complex Three-And-A-Half-With-A-Wiggly-Bit-Thrown-In-For-Good-Measure
stroke system that was the masterstroke behind this engine"

http://www.spagthorpe.com/production/summary.html

And what evocotive names the motorcycles had !
Birddog, Werewolf, Chihuahua, Doberman, Pug ! to name but a few.

The modern era of Spagthorne(R) promises to be as exciting and daring
as the last 100 years.

Long may they continue !

 

Ah, Spagthorpe; a splendid manufacturer of quality motor-bicycles. I feel
certian that, as a connoisseur of such machinery, you would also be
interested in the equally renowned [that is to say, largely forgotten]
builder of the Excalibur, the Empire Excalibur and the Wildebeeste, to say
nothing of the prototype X5 Ladies' Monocycle:

http://www.hurley-pugh.co.uk

 

I say Sir !

A most elucidating and informative website if i may say so, and one by
which the cockles of my heart are warmed immensly by.

 

You absolute *Rotter* Sir !

 

Does one get a grant for such obfuscations ?

For years I have toying with the idea, in combustion engines, of having
valves as part of the piston. The basic idea is to remove any lost
movement from any camshaft/pushrod arrangement. If, by the action of the
piston moving downwards, the valve was naturally opened, to the correct
amount, and for the correct duration (dwell ?) this removes any need to
connect cranks to chains to camshafts.

 

Cracking idea. If you had some sort of one-way valve opening into the
combustion chamber, then the low pressure from the piston down-stroke could
be used to draw the mixture into the cylinder. Some sort of reed or flap
valve would do. If you had the mixture inducted into the crankcase in the
first place, then the piston downstroke could be used to pressurise it so it
went up through the piston via the one-way inlet valve. The succeeding
upstroke could then pressurise the mixture in the cylinder for combustion.
If you could then arrange some sort of exhaust valve to dump the burned
mixture after it had imparted most of its energy to the piston, then you
could have a power stroke on every revolution of the crank. The exhaust
valve would have to be situated so that it wouldn't open at the top of the
stroke, otherwise your bmep would be gone for a ball of chalk. If you
situated it on the side of the barrel, then it wouldn't operate until it was
uncovered by the descending piston. And the pressurised mixture coming up
from the crankcase would help blow the burnt gasses out the exhaust valve.

Thinking about it, if the exhaust valve isn't exposed until you need to vent
the gasses, it would work better if you didn't fit a valve at all, just had
it porting directly into the exhaust pipe. Also, the inlet valve would have
an easier time of it if it was protected from the actual combustion in the
same way as the exhaust was, by being let into the cylinder wall - and if it
was opposite the exhaust port, it would be more effective in blowing the
exhaust gasses out of the cylinder. You'd need to arrange some sort of pipe
to take the pressurised mixture from the crankcase to the inlet, though.

I reckon you're onto something.

--
Platypus - (surreal)
Triumph Trophy 1200 (The Incredible Hulk)
VN800 Drifter (still for sale)
R80RT (for sale - spares or repairs)
Z200 (Fear the Distance Monster!)
DIAABTCOD#2 GPOTHUF#19
BOTAFOS#6 BOTAFOT#89 FTB#11
BOB#1 SBS#35 ANORAK#18 TWA#15

 

Bwaaaaaahahahahahahahaha!

--
Cammo
VT500 Rat
GSX750SE Katana
GT250-X7
GT380
http://cammo.webs.bikers-engine.com
cammo at bikers-engine dot com

 

<snip>

Heh, what sort of weirdo would have a bike with an engine like that.

 

That's nice.

 

How about using hydraulics to open valves. If the action of the piston
moving down - or up for that matter - was used to open valves, would
this not be efficient ?

I also had a design in mind once for a spherical valve that would be
continually spinning, a bit like a needle roller bearing, difficult to
describe here though.


1. I know F1 cars use hydraulic valves - are they not operated by
electric solenoinds ?

 

Klaatu wrote

It is called a transfer port.

 

mups wrote

Lozzo.

 

As in 2 smokes ?

Like: http://www.madsens1.com/anieng.htm ?

 

Thank you Mr Murray.

 

steve auvache says...

I hadn't realised the Thunderace, GPZ500 and CB250RS were 2-strokes.

--
Lozzo : The anti-Timo
YZF1000R, GPZ500S, CB250RS x3
BOTAFOT#57/70a, BOTAFOF#57, MIB#22, TCP#7,
ANORAK#9, DIAABTCOD#14, UKRMT5BB, IBW#013, MIRTTH#15a/16,
BotToS#8, GP#2, SBS#10, SH#3, DFV#14, BONY#9.
Url for ukrm newbies : http://www.ukrm.net/faq/ukrmscbt.html
http://www.glfuk.com/ for MJK Leathers in the UK.
Artificial intelligence is no match for natural stupidity.

 

Lozzo wrote

I thought we were talking about weirdos riding motorbikes.

 

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dr Ivan D. Reid"

Ricardo, afair, invented a rotary valve in the 1920s. It's all been done
before, the only thing that stood in the way of things taking off was
the inadequate materials science of the day.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

 

I haven't, but I wish that I had.

Yes, Pneumatic.