My God, could you imagine trying to ride a bike with a 16 litre engine?

No test rider lived to tell about what riding a Spagthorpe Mastiff was really like… But the bike itself was never hurt, even after taking several 200+ mph tumbles, and needing a new front wheel and two new sets of forks.

That is an unfortunate chapter in the proud history of the Spagthorpe Motorcycle Company. This high casualty rate is, by the way, what led to the development of the Spagthorpe War Mastiff.

Motorcycles spotted at Walt Disney World

The spousal unit and I recently spent two weeks in Orlando Florida. We spent several days at the 50th World Science Fiction Convention, and the rest of the time at Walt Disney World. One of the new spots at WDW since we were last there in 1988 is Pleasure Island, a complex of nightclubs and shops that is open from 7PM to 2AM.

My favorite nightclub there, so much so that we spent nearly every evening there with other folks from the Convention, was the Adventurers Club, a take-off on the classic 1930s style stuffy gentlemens’ club. But in this club, you can never tell when such characters as Professor Otis Wren, the self-important club treasurer, Hathaway Brown, renowned aviator and bug expert (his smoking crashed plane is just outside), or Pamelia Perkins, the sexually repressed club president, is going to make an appearance to talk to the guests. Great fun. Kungaloosh!

Anyway, near the entrance to the Pleasure Island was, to my surprise, an Ariel Square Four, looking to be in restorable condition. Some bastard had cut the distributor wires (I carefully placed the cut wires back in the distributor cap for appearance's sake). Apparently it's only a display piece, and Disney fans will appreciate the joke. I looked for serial numbers on the engine block and frame, but no luck.

I was already giddy with the idea that someone in the Disney organization (which I already have a great deal of admiration for) thought of this. Little did I know that the best was yet to come.

I spend a few minutes wandering around the outside of the Adventurers Club one evening, waiting for it to open late because someone had booked it for a banquet. Around the far corner sat another display piece, perhaps more in keeping with the theme of the Club. I swear to you, my knees grew so weak I thought I might fall. It was a Spagthorpe Mastiff, with sidecar, in what appeared to be in very close to running condition. Most all the running gear looked to be intact, although the rear double-chain was missing, and the ornate crested cover to the oil tank was gone (and from what I could tell, the oil tank was empty too).

Where the Ariel was black and chrome (and looked damned good), the Spagthorpe was British Racing Green with gold accents. Stunning. Had not the lithium battery in my camera decided to die during the NASA tour several days before, I could have captured this for the photo archive. As it was, this alone may have been worth the price of admission to Pleasure Island.

Resurrecting a Spagthorpe War Mastiff

by Michael Roeder

After last year's winter holiday in Colorado—the family was quite surprised to be awaked from their weekend-long post-Thanksgiving nap by the roaring arrival of my beautifully restored 1975 Spagthorpe Pit Bull. Young Neville insisted on taking a ride around the neighborhood, but since he hadn’t been properly trained in the operation of a motorcycle with a sidecar (let alone one with the complexity of the Pit Bull and its attached Albino-Bulldog), we rolled out the spare from the rear compartment of the sidecar. Neville quite enjoyed riding the 1993 Spagthorpe Chihuahua (not to be confused with the Chihuahua of the 1970s, which would have fit, but its unreliability would have defeated the purpose of a reliable spare), particularly on the long straight stretch of 6th Avenue west of Federal Boulevard. By the time the Denver police realized that it was not a P-51 Mustang that had just buzzed him, Neville had already disappeared down the far side of Floyd Hill—I decided to ride on to visit East Tennessee and North Carolina, to take on Deals Gap and the Dragon.

Neville rode alongside in the forward compartment of the Albino-Bulldog. Because the spare in the rear compartment weighed only an eighth of a ton and the weather was cold enough not to need the air-conditioning in the front compartment of the sidecar, we were able to keep the fuel consumption down to an economical 16MPG.

While at student at the University of Tennessee in Knoxville, I uncovered a document published by an aircraft dismantler in Virginia, who was contracted by the government during W.W.II to dismantle captured German warplanes for the purpose of analyzing their technology and construction techniques. The experience of these unheralded workers helped greatly to improve the American state of the aeronautical art. As it turns out, they also severely affected the progress of American motorcycle manufacture. Since the findings of the breakers had long since been declassified, their yard were open to the public. Completely unable to resist the temptation of possibly uncovering some obscure piece of aeronautical history, Neville and I extended our trip and paid the yard a visit.

There can be no doubt that the Messerschmit KR200, in production 1955–1964, was inspired by the Spagthorpe Mastiff.

While I was poking around in the mostly gutted fuselage of a Boeing B-17—a half-baked concept that involved its rotating gun turret and a 1975 Hugemobile station wagon was stewing in my mind—Neville found something that resembled a cross between Little Boy and a Dempster dumpster. Upon closer examination, its features, long since camouflaged by a thick growth of wistercias and dandelions, became clearer.

The nose of the shell held a busted-out headlight—its gleam in the sunlight had attracted Neville's attention—and soon, with the assistance of a machete borrowed from local cigarette plantation workers and tire irons from the Pit Bull, other features came to light. It appeared to be a cross between a Messerschmitt and a Herkimer Battle Jitney. Smaller than the Herkimer but larger than the Messerschmitt, it had fewer wheels than either: two, to be exact.

We found and opened the hatches for the engine compartment. The experimental gas struts had long since become flaccid, so we had to prop the hatches up with the machetes. Imagine our luck when we discovered, tightly squeezed into the generous compartment, what appeared to be the complete engine of what could only be a Spagthorpe War Mastiff!

The motorcycle's 16-liter engine was a little monster: six 1800cc pistons and four 1300cc pistons in a complex W arrangement with three heads: one twenty-valve four-cylinder bank in the center flanked by a pair of eighteen-valve three-cylinder banks. The central pistons had five valves each, three intake and two exhaust; while the flanking pistons had six valves each, three intake and three exhaust. These were operated by a complex set of hydraulically actuated valve lifters, with camshafts located two over each cylinder bank and two more in the gullies between banks.

Slide rules, HP-32s, and graph paper in hand, Neville and I analyzed the complex valve actuation system. Our analysis was delayed until we traced a set of hydraulic lines associated with the transmission, the carburettors, and the valvetrain up to the pilot's compartment, where they connected to the right-hand grip. The entire engine management system was hydraulically controlled by throttle position! So, assuming a 30-weight oil (multiweight oils not having been invented until after the war, I had to explain to Neville), we concluded that at small throttle openings only the smallest set of intake and exhaust valves would be active (actuated by rocker arms and lifters driven by the gully-positioned camshafts), enabling the engine to idle smoothly and quietly. With increased throttle openings, more intake and exhaust valves would be actuated. Neville and I looked at each other with astonishment: At maximum throttle, this engine should produce about a thousand horsepower!

Could the Herkimer Battle Jitney be a distant relative of the Spagthorpe Mastifff?

We returned to the breaker's office and made an offer on the Dempster dumpster under the B-17. The crazy old lady behind the counter grabbed my tie and told me that she was going to junket the next day, so I doubled my offer. She laughed a hearty laugh, took my hundred bucks, and handed me the keys. Neville, bless his young heart, didn’t make a sound. I could tell he was working very hard to contain himself and not snicker.

Resurrecting a W.W.II-era battle motorcycle is not a weekend task, so we rented a garage-sized space at a nearby self-service storage locker. We hitched the Mastiff to the big Pit Bull—it would not fit in the sidecar—and drug it to the self-storage. A quick jaunt on the Chihuahua took us to a nearby car parts store where we stocked up on supplies: six gallons of engine oil, four oil filters, ten little air-filters, two dozen spark plugs, a quart of brake fluid, three muffler bearings, and a bottle of blinker fluid. Luckily, the Pit Bull's roadside repair kit contained the necessary oil drum and it appeared that its tools would fit the Mastiff.

We drained the engine oil and removed the oil filters one by one—it was a tight squeeze to get the one at the front of the inner bank of cylinders. Having changed the oil, we wondered about that complex hydraulic system. Poking about the engine revealed a curious thing, what appeared to be a PTO but was completely inappropriately positioned for that purpose (and who would want to run a combine off a motorcycle?) but was somewhat conveniently positioned for a left-handed mechanic standing with his back to the side of the hatch. The device was attached through a slip-clutch to one of the hydraulic system's redundant oil pumps. We could turn the coupling and precharge the entire system with control oil. Bleeding the system was thus a relatively simple sixteen-step procedure.

Replacing the spark plugs (two in each cylinder in the top bank and three in each of the flanking heads for a total of twenty-six) took only a couple of hours. The simple magneto ignition was slightly complicated by the engine management system but appeared basically sound. We considered building a custom breaker ignition, but decided to delay this project until our return to Denver —and after we had figured out the firing order.

The air filters were fairly straightforward, if tedious, to replace: one for each of the six carburettors feeding the flanking cylinder banks and one for each of the four carburettors feeding the top bank. It appeared to us that the Spagthorpe engineers had not spent a great deal of time thinking out how this engine should breathe. The complete lack of intake ductwork— indeed the lack of intake grilles on the outer hull—was perplexing. We would deal with this problem when we got to it.

We refilled the battery with some Seven-Up and, this being a military vehicle, recharged it from the Pit Bull's 24V generator. While waiting for the batteries to charge, we replaced the muffler bearings and the blinker fluid.

A recently uncovered early concept sketch of the Spagthorpe Mastiff

Finally, the moment of truth: Time to start the engine. A poke at the starter lets the engine spin for a moment, then cough, sputter, and die. This is promising, but we had the feeling that we had neglected some important detail. Acknowledging that we were not experts in British motorcycle technology from the late middle of the previous century, we shut down the Mastiff, locked the storage space, and head out to Knoxville for a quick look at the engineering library. As it was a ride of several hours in the Pit Bull, I checked out Neville on its theory of operation and let him have a few hundred miles at the controls.

While I visited the engineering library in the basement of Buehler Hall, young Neville visited the electrical engineering department in nearby Ferris Hall. I found the volume I was looking for, a user manual for the Spagthorpe War Mastiff, which I copied and replaced on its shelf. Perhaps reading this document would give us a clue why the engine would not start. Neville rejoined me from his exploration of Ferris Hall and we had a quiet lunch at Sam & Andy's on Cumberland Avenue near the campus. Occasionally glancing up form our reading materials—my User's Manual and Neville's UT Daily Beacon—we noticed that the Pit Bull had attracted a small crowd of admirers. We finished our meal and, after a short conversation with the Pit Bull's admirers, we hit the road.

The Problem Diagnosis section of the user manual was appropriately large, so it took us a while to track down the cause of the War Mastiff's refusal to start. After about ten minutes of following complex diagrams form page to page (this was written, after all, at a time when flowchart-optimization algorithms hadn’t been worked out yet) we put out finger on it: No fuel in tank. Doh! Luckily the Pit Bull had three spare Jerry cans, and, being the careful trip planner that I am, they were all filled. We emptied one of them into the War Mastiff's large fuel tank, and tried again.

This time the engine roared to life, shattering a few panes in the storage space's door, but otherwise causing no damage. The clattering cacophony of the valve train was alarming, but it soon subsided to a dull rattling as the oil pumps filled and developed operating pressure. A few blips of the throttle showed that everything was fine ... and cleared out the mufflers of half a century of accumulated cobwebs, grass, mice, and a pigeon.

A recently discovered concept illustration of the Spagthorpe Mastiff. In this illustration the transparent body shows off the 16-liter W-10 engine. Actual Mastiffs were painted Spagthorpe Racing Green, while War Mastiffs were painted Spagthorpe Military Green. The yellow globe is the fuel tank. The exhaust pipes, here illustrated in brown, give new meaning to the concept of "straight pipe."

The last day of our week of rent was upon us, and we needed to find tires for the beast. Now where were we going to find tires in 12x20 and 15x25 sizes? We noticed upon returning from our quick jaunt to Knoxville that the local Big O Tires was having a sale. So we blipped on over. The salesman looked at us as though we were from Mars, but went into the back to look for the sizes we needed.

"Well, I’ve got good news and bad news. The good news is, I’ve got two of each of these. The bad news is, they’re motorcycle tires—round profile. Won’t work on yer truck."

We sighed and asked their price. He named it, then reduced the price as though he wanted to get rid of them. Done! We bought all four, including mounting and balancing for two of them. Neville brought in the wheels, and the sales man smiled.

"I knew you two were up to something! Well, let's see ... yep. I can do these up for yah."

So we returned to our rented space and mounted the wheels on the Mastiff. Luckily, the Mastiff's tool kit included a lug wrench with planetary-drive reduction gearing, and soon the bike was shod with new rubber. We flipped for the honor of being the first test rider. I figured that Neville's youthful bravery and experience with the little Chihuahua would balance my mature experience and technical skill. Neville won the toss. As he donned his riding gear, I reminded him that no Spagthorpe Mastiff test rider ever lived to tell the tale. Neville promised to take it easy, climbed into the War Mastiff, sealed the hatch, and started off. With a thunderous howl, the motorcycle rolled out onto the street and thence to the Interstate. I could hear its growly-howly exhaust note for many miles away. After a half an hour he returned, an enormous grin on his face. It was a testament to his restraint that he had not attracted the attention of the local constabulary.

The War Mastiff was alive.