I kept a scrapbook of technical bits from MCN and MCW from the late ‘70s to the late ‘80s and articles from the monthlies, when there some weird and wonderful devices around, and also took photos of any I saw when at meetings – I might dig some out when I have a moment.
The queen of the hub-centre solos was ‘Nessie’, the Mead & Tompkinson endurance bike (or rather bikes, the 2nd one was most successful, with a Z1000 lump) which raced in the 1970s in the Bol D’Or etc; it had Difazio front suspension, parallelogram swinging arm, and underslung fuel tank.
I think Norman Hossack devised the girder double-wishbone (above the wheel) front fork, the design used on the Fior bikes but in alloy which looked very tidy. I saw a European 250cc race at Donington in 1985 where there were two of the TZ-powered ones, before they moved into GPs with the Honda 500-powered ones and then finally the one with an inline 4 based on sidecar racers’ version of the TZ500 (with 3 pipes coming out of the seat).
Then there was the B.U.T. built by former racing driver Eric Offenstadt, using cast magnesium chassis with trailing-link cast front suspension; the TZ-powered version got a 4th place in a GP.
Tony Foale has his own webpage with lots of interesting information about his bikes and principle of design:
One of the oddest engines was the ADM (Auf Der Maur) vertical flat-4 2-stroke disc-valve solo (this was before he built sidecar engines) with longitudinal crank and 2 carbs each side. It was put in a neat solo bike but never got past testing; it did get a feature article in Superbike mag though.
Kawasaki in about 1978 did an experimental F750 with 4 cylinders on 2 cranks but not in a square, the rear cylinders were further apart than the front ones.
Various people did home-brewed TZ conversions to reverse the cylinders or to make it disc-valve; there was one that had a disc on the front of the crankcase driven by belts turning 90 degrees from the end of the crank.
On anti-dive, Honda used the adjustable lever from floating front calipers to under the headstock on F1 bikes for a while in the early '80s, as did Kawasaki on one of their 500 GP bikes that had a monocoque chassis.