Mad Yank on a
Monowheel
[From No.199 - May 2004] - 3 video clips to watch

Kerry McLean went so minimalist he built a bike with only one wheel. Rod Gibson got a closer look..

THE concept of a single wheeled motorcycle is one which has intrigued designers through the ages. Various people have experimented with the format but the idea has never really caught on, partly because the single wheeled layout is inherently unstable without significant design and development, and the end result has never really been enough to justify the time and resources required to make it work. So the monocycle, or monowheel, has remained a novelty on the sidelines of motorcycle development history. Until Kerry McLean came along, that is. Kerry is no stranger to oddball engineering projects, having spent much of his formative years in Michigan building Hot Rods, Trikes and jet propelled bicycles. When he first started experimenting with single wheeled motorcycles back in the mid seventies he found the problems inherent in the design were far from from insoluble, and over the next thirty years devoted much of his spare time into making the concept work. The result of all this work is a handful of machines built by Kerry, each one carefully hand made and each one taking development further as he's learned lessons along the way.

Monowheels present a number of challenges to the designer, and several compromises have to be made to get everything to gel together into a functional machine. The first problem is stability. The monowheel depends on gyroscopic effect to keep it upright. As gyroscopic effect is proportional to rim speed, smaller diameter wheels become stable at lower speeds than large ones. Tall wheels feel top heavy to ride, and present a considerable challenge to the rider to get moving fast enough to find stability. Adding low-down weight can counteract the top heaviness to some degree, but weight can create its own problems.

After last month's dramas sorting out bent forks it was something of a relief to get back to some straightforward assembly work, though as is always the case when working from a box full of bits I kept finding I had to keep stopping to order pesky circlips and washers. No matter how carefully you sort a project like this one, if you didn't dismantle the bike yourself and keep notes there will always be an element of the jigsaw puzzle about assembling it.

Filling the tank with 20:1 two stroke mix I turned it on and began to prod the kickstarter when I noticed that fuel was pouring from the tap where it screwed to the tank, as well as gushing from the carb overflow. So, despite a hint of life from the engine, I had to stop straight away and postpone the start up until I could source the correct sized fourpenny fibre washer to seal the tap to the tank. Then it looks like a session with carb float needles will be required. But to all intents and purposes the bike is finally assembled, and another half hour's setting up will see it ready for an MOT.
It's been a long and expensive haul for Brian, who first asked me to assemble the bike back in December 2003, and I would like to thank him for being so patient as the job ran late and went over budget by about 25 per cent.
But, alas, that always seems to be the case with any restoration project and the finished result will do him proud. Watch out for the little Fizzy at VJMC shows in the North of England this year, and if you still have a rusting example locked away in the back of the coal shed; dig it out and break out the spanners. You know it makes sense.

Rod Kickstarts and zooms off! (Click Image to open video window) [DOWNLOAD MOVIE]	Big grin on his face, Rod returns! (Click Image to open video window) [DOWNLOAD MOVIE]
(Quicktime(tm) Media)	(Quicktime(tm) Media)

On the Dyno

Determined to find an answer to his bike's sluggish running, Rod Gibson enlisted the help of local dyno expert Max to finally nail the mystery of the super-rich Kat.

With the bike at speed, Max hits the button to start the computer programme.

Simply catching sight of the very clean white-and-red RD250E had brought back a few memories, and starting the engine really transported me back in time. The Yam fired up first kick with that raucous, clattery, off-beat rakka-tack-tack of an exhaust note from its twin pipes, along with a small cloud of two-stroke exhaust smoke that provided the perfect, atmosphere-enhancing (and polluting) accompaniment.
I'd been looking forward to riding the RD250E all morning, and now I was really hooked. It's a long time now since the late Seventies, when there were so many of them on the roads. But even now there's something about Yamaha's coffin-tanked twin that seems to sum up all that was best and craziest about the days when, for teenage speed freaks on a provisional licence, a hot Japanese 250 two-stroke like this was the height of motorcycling performance.
Ten minutes later, its engine warmed and the road ahead clear, the Yamaha revved hard through the gears while I held its throttle wide open, slid back on the seat and crouched down to help make the high-handlebarred RD as aerodynamically efficient as possible. The speedo needle crept towards 90mph, the engine screamed, the scenery rushed by... and it was very easy to understand the phenomenal sales success of Yamaha's aircooled, two-stroke parallel twins.

Max runs the bike up through the gears. All the runs are done in fourth gear.

This RD250E was registered in 1980, the year that the RD250LC and its 350cc sibling were unveiled, beginning a new era for Yamaha's two-stroke roadsters. That was also the year the King Kenny Roberts won his third straight 500cc world championship, reinforcing the image of a two-stroke Yam with speed-block paint scheme as just about the fastest, snarliest thing on two wheels. (Ironically, Kork Ballington and Kawasaki had by this time taken over the 250cc class.)
The story of Yamaha's twins had begun a long way before that, of course. This bike's blood-line goes directly back to 1957 and the YD-2, Yamaha's first aircooled two-stroke twin, which was developed from the company's very first motorcycle, the 125cc single-cylinder YA-1 Red Dragonfly of two years earlier. A few years later came the YDS-2, a more powerful and sophisticated 250 twin that was unleashed on export markets worldwide in the early Sixties. Yamaha's reputation for fast and furious two-strokes was enhanced by the firm's grand prix success, notably in the 250cc class, where Phil Read won three world championships in the Sixties. The world titles kept coming into the Seventies, with Britain's Rodney Gould, Read again, flying Finn Jarno Saarinen, and Germany's Dieter Braun continuing the run between 1970 and '73. In that year Yamaha renamed its new roadster the RD250, the initials standing for Race Developed.

The bike test in video (Click Image to open video window) [DOWNLOAD MOVIE]

Order from chaos

Tony Ingrey’s Harley-powered ‘Sporton’ is the latest in a long line of hand-built specials to emerge from his dark, satanic workshop. Rod Gibson braved the Yorkshire Moors to find out more.

As an apprentice in a bike workshop I was taught that, for any well-prepared bike ever to see the light of day, a clean, tidy and well-ordered workspace was essential. For having a tidy workshop creates the right mindset to build tidy bikes, and chaos can only breed chaos. Most folks seem to agree. But among our number, as with everything else, there has to be the odd exception that proves the rule. I’ve known Tony Ingrey, the owner of this remarkable Harley-engined special, for what seems like forever, and each time I’ve visited his engineering shop in Huddersfield I’ve felt myself in mortal danger from the piles of parts, engines and raw mild steel laying around apparently at random. Cables, tools and boxes of parts clutter the floor, and neglected empty coffee cups grow strange and unusual fungi in their forgotten resting-places among the lathe beds. But to those with a trained eye and a stiff constitution, the place is a grotto of exciting possibilities as half-built classic Harleys, Z1000s and the odd Volkswagen trike emerge from the gloom.

The bike on test (3 different ride-bys) (Click Image to open video window) [RIGHT-CLICK TO DOWNLOAD MOVIE]

Better then new - our Honda CB750 runs

Our Project CB750K1 hits the road as Editor Rod adds the finishing touches to the restoration.

I'm always a little nervous about taking a freshly-restored bike on the road for the first time, particularly when I don't own it. Tim has waited patiently for some time to see his pride and joy run again, and the last thing I want is to inadvertently scratch the new finish, or worse. However I can't announce myself satisfied with the rebuild until I've put a few test miles on the bike, and made sure everything works as it should.

My brief test ride reveals an engine that feels crisp and smooth and willing to rev, though in deference to the new pistons and bearings I'm watching the tacho like a hawk and keeping the revs below 4500. I'll be advising Tim to do the same for the first few hundred miles, then to give the bike a full service at 500 miles, just like a new one. This will allow everything to bed in and settle down, and minor adjustments to tappets and head bearings may be necessary.
The tyres and brakes are new, too, so I'm not going to be wellying the bike around too hard and exploring the limits of its handling.

But there is a rather vintage feel to the steering, aided, no doubt, by the dated fork design and original rear shockers. Given a few miles to get used to, it will be fine, and all the work on the front brake has paid off with a powerful, responsive brake that will only improve as the new pads bed in.
All in all, a most satisfying maiden voyage, and Tim should enjoy the bike for many thousands of miles.

Katana hits 120bhp - Sept 05

Who let the Kat out?

120bhp and an 11.42 second standing quarter from our project 1260 Katana. And it still isn't finished yet…

Over the winter the bike was stripped to its bare bones, and then slowly rebuilt with the 1260 kit, a fully braced frame, and wheels and front suspension from a 1996 Kawasaki ZX6RF1. Each time I encountered a problem, (and there were a few to solve along the way), a solution presented itself, and I'm eternally indebted for the help and advice I got from parts suppliers, specialists, and ordinary readers who took an interest in the project and gave me invaluable tips based on their own hands-on experience. Somehow it made the bike a real team effort.
So how does it go? Well, on the road the bike is much torquier than it used to be, with the same kind of mid range grunt I've experienced on bikes like the FJ1200. There is a touch more vibration through the bars and footpegs at 4-5000rpm, but its nowhere near the lumpy, unrideable monster I'd been warned I could end up with. The lower front end, tighter suspension and 17" wheels make it so much easier to drop into fast bends, aided by totally modern Michelin Pilot rubber, though the original rear shockers are letting the side down a little. And those ZX6R calipers are such an improvement over the original single potters that high speed braking is much more secure. The problem now is keeping it down to legal speeds as it simply gallops effortlessly along, devouring mile after mile of fast A and B roads and always leaving me wanting more. This is a bike you want to ride, and arriving somewhere is always a bit of a disappointment.

So, lets crunch some numbers. The bikes first dyno run saw it running the 1260 kit and K&N filters, but the motor was in otherwise stock trim with the same carbs and pipe from last year. I'd plug chopped the carbs repeatedly and had ended up on 160 main jets (up from 97.5 in stock trim with the standard air cleaner). On the rolling road at Dynomax it showed an astonishing 78.91 lbs/ft of torque, with the curve almost flat from 3500rpm until 6600rpm. "That's more than an R1!" exclaimed Ian the dyno man, rushing off to produce a printout showing a figure of 76.30ft-lb, peaking at 10,000rpm, for the last R1 run they'd done. The improvement is almost all down to the 1260 kit, and is a huge step up from the stock engine’s 58ft-lb @ 6500rpm we got from the bike last year. I was mildly disappointed with the bhp reading of 103.3, peaking just past 7800rpm. Up from last year’s 84.9bhp, it was still a marked improvement, and Ian advised the figure would improve as the (still tight) motor loosened up. The dyno also showed it was slightly rich at the top end.

In this trim I took it to the Straightliners meeting on May 29th, and pulled an 11.76 second run with a terminal speed of 116mph. A marked improvement from last years 12.96 and 103, but still some work to do. Apart from developing my own technique (and drag racing is a skill that has to be learned), it was obvious that the gearing was all wrong as I was crossing the line in third gear with the tacho needle buried into the red. Clearly overgeared.
For the next meeting at Elvington I'd dropped to 150 main jets, and geared down from a 39t rear sprocket to 42t. Best time for the day was 11.60 at 115mph, putting me half way up the 11.30 class in eighth place. An improvement, but more was to come.

Motad exhausts had by this time very kindly offered to have the bike in their workshops to see if any performance gains could be had by replacing the unknown 4:1 pipe with a more modern system. A visit to Motad in Walsall turned out to be a fascinating day out (more of which in our December issue), but the first revelation came early in the day. Motad ran the bike on their dyno when I arrived, so a comparison run could be made later with the new exhaust. Amazingly, the bike now showed 113.00bhp at 8788rpm, up 10bhp from Dynomaxs original reading with no work other than a jet swap and a good thrashing. Of course the two dynos could be slightly different in calibration, but the bike had clearly improved with use.

While Motads Rob Limbrick took me around the factory, John and Charlie got busy with a selection of header pipes and tube benders to find a way to mate a Venom Perfomance end can to the 23 year old bike. They ended up with four stock header pipes from an aftermarket GSX1100 system, mated to a one-off intermediate pipe specially made to locate the Venom titanium silencer where it wouldn't deck out too early. The resulting system looks rather long, but locating the silencer higher would involve surgery to the pillion footrest mounting loop on the frame, which is hardly worthwhile at this stage. Popping the bike back on the dyno, jaws dropped as Charlie ran the bike up to speed and read off the new bhp curve. 120.00bhp at 8415rpm, a 7bhp gain just by changing the exhaust system. A crowd gathered around the dyno for celebratory whoops as the curves came off the printer, and I suited up to relish the ride back to Lincolnshire. Make no mistake, the guys at Motad are as much bike enthusiasts as you or I, and are happy to take on skilled one-off work like this when they can.

[Buy this issue!] - [Articled edited for online reading]

kawasaki 900

Good times roll again!

Our project Z1A is up and running at last. Rebuilder Rod downs the spanners and picks up his crash helmet to try out the finished bike.

First of all, a confession. While some of our more dedicated readers have been following our Z1 rebuild series with baited breath to see how it all turns out, I've actually been riding the finished bike around all summer. And before I get deluged with cries of 'fakery' let me explain. The vagaries of publishing schedules meant that the series in the magazine has been lagging behind actual work on the bike, which was completed just in time to go on show at Donington in February 2007 – just exactly a year after I bought it as a wreck at the same venue.

But like all rebuilds it's taken a few miles and bit of tinkering to get everything set up and working just right – more of which later. But first let’s deal with the one major task I couldn't handle with a spanner – getting the bike registered for UK use.

The project bike came without any UK registration papers, though it did have a bill of sale, a certificate to show import taxes and VAT had been paid, and the original Utah registration document. With the finished bike up and running I needed to apply for an age-related plate. Jerry Humpage at the Z1 Owners Club kindly supplied me with a dating certificate, confirming the model and year of the bike based on the frame and engine numbers. I then needed an MOT certificate and insurance before presenting the bike at my local DVLA office for inspection.

For the MOT I loaded the bike into the back of the company Transit and vanned it down to the local dealers, who happily issued a pass certificate on the frame number. Thinking I had all the time in the world I then casually insured the bike on the frame number, and popped down to the DVLA office with the paperwork to see what to do next. Although they insisted on the phone that they wouldn't need to inspect the bike, when I turned up in person they decided that they did. I made an appointment for the following Wednesday, the first slot they had available.

On the appointed day I vanned the bike over to the DVLA office with the paperwork, and hung around whilst the DVLA man inspected the bike in the back of the van with his DVLA maglite, presumably to confirm that it did in fact exist. He then made to move off, taking my papers with him and mumbling something about issuing a tax disc and reg number in the post.

- End of online sample -

From December issue 242. To order your copy >>

Z1A video clip

To see the Z1A rebuild video clip >>

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