B. N. G. Spagthorpe:
Pit Bull/Rhino

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  • Concept Illustration with R75 for scale.

    Jim Buchanan provided us with this most loving description of the Spagthorpe Pit Bull:

    Well, last weekend I did it. I got the Britbike I’ve been wanting. I was picking up some papers for recycling from my wife’s aunt Tabitha. When I went into the garage to get the papers, there it was, a Spagthorpe, with a factory sidecar. I didn’t even know what model it was, but I had to have it. When she saw how interested I was, Kris’s aunt explained that it had belonged to her late husband, and that I could have it if I took good care of it. Wow!

    She hasn’t been able to find the title, and I’m still not quite sure what model and year it is. It appears to be from the early eighties. Naturally, my first thought was to ask on the ’net. Of course, I have some technical questions as well.

    On the upper fuel tank there is a badge with a picture of a rhinoceros, so I suspect that it is a Rhino. Of course, the tank from a Wolfhound would fit too from the looks of it, so perhaps this doesn’t prove much. A friend of mine says that the Rhino’ is just a re-badged Pit-Bull. Apparently, sometime in the early ’80s a rider was mauled by the layshaft of his Pit-Bull, and this plus the reputation of th canine of the same name, and the litigious nature of the US, led the importer to re-badge all Pit-Bulls as Rhinos’.

    The engine is a flat, opposed seven (the place where the eight cylinder would go is taken up by the reciprocating power-steering pump). Estimating the bore and stroke, I’d guess that the engine displaces about 2.6 liters.

    In a novel twist on turbocharging, there is a six cylinder reciprocating external-combustion engine above the main engine. This is powered by the exhaust of the lower, main engine. The output of this second engine is used to run a unique scroll-shaped positive-displacement supercharger. This blower resembles a rotary steam engine made around the turn of the century, which I saw at the Giles Peach museum in Detroit a few years ago.

    The engine is fuel injected. There is an injector at each intake port (note: 4 of the cylinders have two valves and one intake port, 3 of them have 4 valves and two intake ports, I assume this is to broaden the torque curve, like most Spagthorpe tourers, this is a fairly heavy bike). These injectors are connected, via stainless-steel braided lines, to what can best be described as “fuel distributors". There is one distributer per side, each suppling 5 injectors. The “distributors” are made of cast-iron and are painted black. There is a plunger in the center which moves up and down under the control of an aluminium disk that rises and falls inside of a machined aluminium cone which is behind the “distributer". Both this cone, and the “distributer” are mounted to the top of the air-cleaner housing. The air cleaner is a rectangular pleated paper thing. The “fuel distributer” seems to work due to 5 separate pressure regulators that keep a constant pressure across slots which are covered/uncovered by the plunger. This results in controlled fuel flow to the injectors.

    The flywheel is at the front of the lower engine and is connected, via an exposed chain, to a layshaft above the top engine. Both the alternators, the 24V unit which is used for charging the batteries, and the 48V, 400Hz unit that is used for lighting and accessories, are driven, also via chains, from this layshaft. These alternators are located in front of the left and right lower fuel tanks respectively.

    The output of the 24V alternator is rectified via a synchronous rectifier. The sparks it throws out at night are beautiful! Who needs neon?

    The 48V alternator is held at a constant speed via a set of fly-weights that slide a chain back and forth on a set of tapered sprockets. It only seems to keep the frequency within about 10 Hz of the 400 Hz nominal. This will probably cause problems with the clock, but since it needs to be reset each time the bike is started, perhaps it won’t be too irritating.

    The lower engine is air-cooled, with the added feature of thermostaticly controlled water jets which spray water at the heads when they reach a preset temperature.

    The upper engine is water cooled, with two radiators located to the left and right front of the middle fuel tank.

    The transmission is conventionally located behind the engine, also driven via chain from the layshaft. Due to the high torque output of the engine, I suppose, it only has eight forward speeds. Of course, with the two speeds and reverse offered by the transfer case, there are 16 forward gears and 16 reverse gears.

    The transmission is *very* clunky, almost as bad as my beemer. Perhaps that is due to the unique choice of clutch locations, at the output of the transmission. I’m not sure it would be possible to shift this bike without the hydraulic power assist on the three shift pedals (two on the left side one on the right).

    Behind the clutch, there is a housing that contains bevel gears. There are two shafts going to the rear wheel. The left shaft spins opposite to the right shaft. There is a drive housing on either side of the rear wheel hub where the power is re-combined.

    The wheel on the sidecar is driven, much like the old WWII beemers, only much different. It has a hydraulic motor that is powered by a pump that is located in the lower left saddle bag. This pump is powered off the 48V bus. On top of the middle tank, there is a set of controls. One engages the hack pump, the other, via some sort of device that looks like a 3 phase motor, operates a similar motor-like device at the hack wheel which bypasses oil around the wheel motor. Three phase power for these device is supplied by a rotary converter that is located in the third (from the bottom) left fairing pocket. Nit: sure, this system was an option, but they could have put a little more work into integrating it into the styling of the bike. It looks as if it is lifted bodily from a WWII battleship!

    Brakes: well, there are none, in the conventional sense. Each wheel has a DC generator built into the hub. When the (integrated) brakes are applied by pulling in the right hand lever, field current is applied. The output of the generators is used to charge the left hand battery. To say that the brakes aren’t up to modern standards is to make an understatement! They are ’green’ however! These brakes are either full-on or full-off. Riding a /5 for several years, I’m rather used to that though.

    The side car is nice. It is the Albino-Bulldog model, the one that looks like a Pontiac Transport, only ten years earlier. This is *very* similar to a Hannigen sidecar a member of my local club has on his beemer. Side by side it would be hard to tell them apart. It is set up to haul other bikes. I can fit my R75 into the back compartment easily. Gold Wings need not apply though (at least the six cylinder models). Ramps and tie-downs are provided. To get the other bike in, I do have to take out both of the full-size spares. There is room to put them back before riding though. Only the front compartment has air-conditioning. It is powered from the 48V line. Sadly, the rider has no air-conditioning, I guess you can’t have everything.

    Pit Bull with Albino-Bulldog Sidecar and spare R75.

    The second-most unique feature of the bike is the steering mechanism. There are *two* steering heads! The handle bars pivot on the left assembly, and this connects via a scissors mechanism to the other. The forks are attached to the head bearings via a similar mechanism. One unique feature is a knob on the fairing that changes the geometry of these linkages. When it’s fully in one direction, the steering works normally. When it is in the other direction, steering is reversed. You can counter-steer with the side-car in place! When the knob is centered, there is no steering. I don’t think I’ll be testing this out while moving... The power-steering cylinder is connected to these linkages. The weirdest part of this front end is the actual springs and suspension. It is a leading link assembly, with the pivot point at the lower back of the fender. There are two spring/shock assemblies that attach the axle to the fork at the point that it starts to bend back. These look for all the world like rear shocks. They seem to work out quite well with the ’car though.

    On a bike this size, I’d expect an electric starter. There doesn’t seem to be one. Instead, there is a ’starter console’ on the dashboard. It consists of a lever labeled “store” and “release” below a dial that is labeled from 0 to 100. To start the bike, you place the lever in the “store” position, then kick the kick start lever until the dial climbs to 100. If you kick hard, this can usually be accomplished in about 20 kicks. Then, slip the lever into “release". The main-spring is released and the engine spins over. In the short time I’ve had the bike, it’s never take more than 4 or 5 tries to get it started.

    When starting one of these bikes, make sure that it is in neutral! After I got the bike home, I was showing off the starter mechanism to the neighbors. I’d left it in seventh gear, but I’d forgotten to put the transfer case into neutral. Instead, it was in high reverse. When I slipped the lever into “release", the bike took off backwards at about 70 mph. We were lucky that the engine didn’t start, and that no one was hurt. The bike wound up about two blocks down the road, stuck in a muddy field, among a group of bemused pigs. The farmer wasn’t too bad to deal with, and I’ve fixed the fence already. It was amazing, how straight it tracked though...

    Now that it’s getting colder, I think I’ll really appreciate the heater. It’s electric, of course, with three 1KW elements. At this point, Lucas rears his ugly head. These elements are on the same 100A breaker as the running lights. When it’s cold out, you can only use the three main headlights! When will they ever learn! I had exactly the same problem with my ’59 Greeves-Thorpley Griffin, also equipped with Lucas electrics. As you may recall, the Griffin was a British sports car, that to save weight, had a total-loss electrical system, using primary cells. Unlike many British cars of the era, it had decent heat and lighting, both electrically powered. Unfortunately, in addition to suffering from poorly thought out electrics, the battery added more weight than was saved by removing the generator. In fact, the battery added more weight than could have been saved by removing the engine. Definitely not a car designed by a committee, this vehicle reflected the personality of the designer, Thorpley Peach (Yes the estranged brother of the American industrial tycoon, Giles Peach).

    One part of the bike I’d really like some help with is the radar??? system. Some parts are missing, and I’m not quite sure what the system is supposed to do. In the rear trunk there is a magnetron. About 3KW I’d guess. It is pulsed with power from a capacitor bank that is charged up to several thousand volts via a transformer. The current seems to be switched with a metal-case vacuum tube, probably some sort of thyratron. The output of the mag is connected to a waveguide that forms the backbone of the frame. And some manufactures thought they were clever putting oil in there! At the front of the bike, the waveguide is terminated in a feed horn on a flexible coupling. This whole assembly is behind a ’dome’ or ’nose’ that protrudes between the bottom two headlights. The mechanism that aims this, and for that matter almost all of the electronics are missing. Just cables with military looking plugs on the end, hanging at the back of the equipment rack. This rack is located where the refrigerator would be on a Wolfhound. I don’t see any sort of consideration made for a receiver, but there *is* a round CRT in the dashboard, and its leads end, unterminated, at the same rack as the control lines to the magnetron. Help people, what is this system supposed to do?

    Also, there are unused brackets on the right side of the frame that seem to be intended to mount something long and fairly slender. What are these for? My first thought was a rocket launcher, but it appears that the fairing would block the front of such a device.

    Well, I hope she finds that title soon, I can’t wait to ride this beast into work. Can you imagine the reaction?

    Hmmm, I’ve never named a vehicle before F.B., I suppose I’ve started a tradition, the Spaggy will need a name. Any suggestions?

    Anyone have an “Illustrated Spagthorpe Buyers Guide"? It seems to be out of print. When I asked at one local cycle shop, the owner warned me not to ask that question in public, and to be careful who I deal with for parts. What did he mean?

    Jim Buchanan replied...

    Jim, Jim, Jim, Jim. I hate to be the one to break this two you, but this is almost certainly a clone of the Spagthorpe Pit Bull produced by the Long March Motorcycle Company in the People’s Republic of China. The specific model is indeed the Rhino, a reference no doubt to the belief common in China that the Rhino’s horn has special medicinal properties of a sexual nature.

    The key is the name and the tank badge: since all Spagthorpes are named after dogs, it’s clearly a clone. The Rhino is not known for its reliability. Much of the workmanship is clearly inferior to the original Spagthorpe, and the materials used are of much lower quality; Long March clearly ignored the Spagthorpe quality motto of “Never use lead when gold will do". It is in part this attitude on the part of Spagthorpe that makes the bikes such coveted collectors items. That and the, ah, unique and previously unsuspected engineering principles.

    As you may know, the emissions created by the LMMC Rhino are so bad, it is one of the vehicles on the EPA’s hit list, under the special heading (the so called “red page") “terminate with extreme prejudice". Not only could the Rhino not be EPA certified, just bringing it into the country requires an Environmental Impact Statement. The EPA has the authority to impound not only the Rhino, but anything it may have been in contact with. In Texas, it’s possible to get the death penalty for owning a Rhino. Worse, in California, you can be forced to move to New Jersey. They take it that seriously.

    The LMMC still produces Rhinos for domestic use, although future international agreements with the PRC will probably force them to halt production. Even this will not elevate the Rhino to collector’s status, since my boss recently came back from a business trip to Beijing (NCAR is looking at joint field projects in Mongolia with the PRC’s National Meteorological Center) and reports that the streets are littered with Rhinos, not to mention cast off parts.

    Good luck.

    Front view of Pit Bull showing headlights and radome.


    Spagthorpe Home Story: Jim Buchanan (c22jrb at kocrsv01 dot delcoelect dot com)
    Pictures: Wendell Gunderson-Ogelthorpe (wgundersonogelthorpe at spagthorpe dot com)
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