With the recent passing of Ken Sprayson at 94 years old, I thought it would be timely to look at one of the bikes he constructed a frame for during his over 30 years working on various special projects for famous tubing and fabricating company Reynolds.
This is by far one of the lower profile motorcycles worked on by Ken Sprayson in his long and distinguished life, but the machine seen here is the result of an interesting collaboration between Sprayson and English racer Arthur Wheeler that in 1959 saw the pair develop a new frame for his 250 Moto Guzzi racer.
The design was a success so in 1962 a second frame was constructed to house a 350cc motor.
A third frame was then fabricated for Trevor Barnes who then spent many years racing and developing the bike seen here.
The motor is a 350 cc race unit which was greatly modified by Barnes with many internal improvements including a twin-plug ignition.
Ken Sprayson was generally involved in some way or another with pretty much every frame design used in the British motorcycle industry throughout the 1960s and 1970s. It was Sprayson who fabricated the first ever production Norton Featherbed frame from the designs of Rex McCandless for the Manx Norton.
He also had a special connection to the Isle of Man TT and worked on frame designs with the likes of Geoff Duke, Mike Hailwood and John Surtees.
Sprayson even had a hand in the design and build of the land speed record holding Project Thrust II jet car driven by Richard Noble to a top speed of 1047 km/h. And that only touches on a sliver from his catalogue of works, almost all of which were successful.
Those of you with good memories will recall I covered the DEMM Museum in a column long ago – The DEMM Museum | With Phil Aynsley. Here are images of perhaps its finest product – the 50cc Bialbero which won the 50cc Italian Mountain Championship title in 1961.
DEMM 50cc Bialbero
The jewel-like DOHC motor used a slightly over square bore and stroke of 40 x 39 mm and a bevel shaft to drive the overhead camshafts. An external flywheel was used together with a six-speed gearbox.
Twin plug battery/coil ignition was fitted, while carburettion was by a 16mm Dell’Orto with a seperate rubber-mounted float bowl. Output was 7 hp at 14,500 rpm with a weight of 55 kg, and the bike as seen here was shot in the Morbidelli Museum in 2011.
Unknown Italian manufacturer number 736 – Atala. As with many motorcycle companies Atala (founded by Emerico Steiner) started by producing bicycles, from 1909 in their case. In 1924 they debuted a motorcycle powered by their own 2-stroke horizontal 125 cc motor.
1963 Atala Freccia D’oro (Golden Arrow)
This proved to be a success and lead them to begin making motorcycles powered by 350 cc Blackburn and 175 cc JAP engines. A 500 cc JAP model appeared in 1932. However the company dropped motorcycle production in 1934, returning to bicycles.
The company was sold to Caesar Rizzato & Co in 1938 which continued producing bicycles and reintroduced motorcycle production, still under the Atala name. A range of small 2-stroke models in 49, 98 and 124 cc capacities, usually powered by Minarelli motors, were manufactured.
1963 Atala Freccia D’oro (Golden Arrow)
After 2002 Rizzato holdings passed through several different hands resulting in a new company Atala S.p.A. being formed and based in Monza. In 2011 it became part of the Dutch Accell Group which owns nearly twenty bicycle brands. Atala continues to make bicycles and e-bikes
The bike photographed here below is a circa 1963 Freccia D’oro (Golden Arrow) which uses a 49 cc type P-3 Minarelli 2-stroke motor producing just over 1 hp. This was enough to propel the 56 kg machine to a top speed of 60 km/h. An unusual feature is the use of a twist-grip mounted, cable operated gear change mechanism.
I’m afraid information about these bikes is scant, but as they are such interesting machines I’ll have have to let the photos tell the story. Firstly we have (an extremely rare) example of Derbi’s first 125 cc GP design.
Derbi’s first 125 cc GP design
Race team chief and engineer Francisco Tombas (also responsible for the highly successful 50 cc GP) introduced this narrow-angle, air-cooled V-twin in 1967 and it competed until the completely new water-cooled twin replaced it in 1970.
The twin crankshaft design was basically two singles mounted one above the other with a common crankcase. An six- to eight-speed gearbox was used, depending on the circuit. Two 24 mm Dell’Orto carburettors were fitted.
By 1969 the output was 32 hp at 13,500 rpm and the 100 kg machine was good for a top speed of 215 km/h. The bike was not particularly successful however with only a single top-six placing in GPs. While Angel Nieto did not compete in the 125 GP class prior to 1970 he apparently raced this bike in the Spanish Championship in ‘69.
Secondly we have the only surviving example of the two Derbi 125cc water-cooled twins built for Angel Nieto for the 1970 GP season. He finished 2nd in the championship to Dieter Braun on a Suzuki with both winning four races each. It was later raced by Benjamin Grau in the Spanish Championship.
This is one of the two Suzuki RGV500 XR79 machines built for Kevin Schwantz (Alex Barros received the other two) for the 1993 season. Kevin won the championship with four wins and seven other podiums, while Barros finished sixth with one win and another podium.
Kevin Schwantz’ 1993 RGV500 XR79 500GP
Compared to the previous year’s XR78 that Schwantz and Doug Chandler had finished the season in third and fourth places on, the XR79 benefited from improvements to the power delivery, grip, suspension and overall balance. Newly acquired race engineer (ex-Kawasaki and Honda) Stuart Shenton played a major role in the bike’s development.
The 70º V4 big-bang motor produced more than 165 hp at 12,800 rpm and propelled the 130 kg (no fuel) bike to a top speed of over 324 km/h. Two different engine specifications were used at the beginning of the year, one more hard edged, the other more linear in power delivery, with both having the same peak output. The latter type was used by both riders by the end of the season.
Kevin Schwantz’ 1993 RGV500 XR79 500GP
To increase traction the pre-progammable ignition timing could be retarded in the lower three gears, according to throttle position and rpm. Additionally both power valves and Power Chamber variable exhaust system were used. A power shifter was also employed for the first time on a Suzuki.
The four 36mm Mikuni carburettors were fitted with two electronic power jets rather than the normal single jet. The second jet supplied additional fuel from over 10,000rpm. A major change to the engine for ’93 was casting the crankcases in magnesium instead of aluminium which saved 2kg.
After the end of WW II the Ducati brothers looked to re-establish their ruined factory and unemployed workforce. One avenue they explored was the manufacture of a small car, the DU-4. Only a single prototype was built in 1946 before the growing success of the Cucciolo focused the company’s efforts on two-wheeled transport.
Ducati DU4
The prototype was sold to Fiat where it remained until 2005 (the bodywork went missing during this period). It was then that long time Ducati enthusiast Italo Forni was able to purchase it. Forni is an ex-Ducati test rider (1973-1977) who also competed for the national team in two ISDTs, riding Ducati 450 R/Ts. He went on to be Italian MX champion several times.
Ducati’s DU-4
The DU-4 was quite advanced for the time with front-wheel drive, 4-speed gearbox, independent suspension and hydraulic brakes. The steel tube chassis was made by Verlicchi.
Perhaps the car’s most outstanding feature however was the use of a newly designed OHV 254cc V4 engine, in an ‘L’ configuration with the front cylinders nearly horizontal – the same as Ducatis of 25 odd years later!
Italy is home to a plethora of small three-wheeled delivery vehicles of which the Piaggio/Vespa Ape (Bee) is by far the best known, the Bee entered production in 1948 and is still being produced! Most motorcycle manufacturers had one or more in their ranges and Ducati was no exception.
Ducati Muletto
In 1957 the company introduced the Muletto which was powered by a 175 cc OHV four-stroke motor that used many parts from the earlier Cruiser scooter. The following year the motor was enlarged to 200 cc. This had a carrying capacity of 350 kg and a top speed of 60 km/h. The gearbox had four forward ratios plus reverse. The 1958 model is what you see here.
Ducati Muletto
Versions were available with open, partially and fully enclosed cabs. The Muletto was not a big seller and was only produced for two years. However a new version was planned and reached engine prototype stage before being abandoned. I was able to photograph this at the factory in 2007.
200 cc Muletto prototype motor and drivetrain
The red stripe was a government requirement for transport/for-hire vehicles.
Ducati returned to the three-wheel market with the Fatterino which was produced from 1962 until 1965 and used a 48 cc two-stroke engine that was equipped with a fan attached to the crankshaft which forced air into an alloy shroud that covered the barrel and cylinder head. A three-speed gearbox was used. Again three cab configurations were available.
Count Agusta and Giuseppe Gilera were fierce rivals during the 1950s, so after Gilera introduced their B300 twin in 1952 it was deemed necessary for MV to counter it. Enter the 300 Bicilindra prototype.
The MV Agusta 300 Bicilindra was produced to compete with the Gilera B300 twin
The bike was shown at the Milan Show in 1955 with production due to start the following year. However the design by Carlo Gianini – who was also responsible for the Gilera Rondine and ’53 Guzzi 500/4 was deemed too expensive for production.
This prototype sat abandoned in a corner of the factory until 1986 when it was purchased by Mr Elli, along with many other bikes and spares. He held onto it until 2013 when he sold it to Ginetto Clerici who then (with Elli’s help) restored it.
MV Agusta 300 Bicilindra
This proved to be no easy task as the motor never had any internals! However both Clerici and Elli were familiar with designer Gianini and knew the intended form of the internals. Drawings were eventually unearthed with the assistance of Erico Sironi, director of the MV museum.
The standout feature of the motor is the valve operation. Cam drive was via two large gears, one above the other and driven from a gear on the crankshaft between the cylinders. The top gear featured a single cam lobe on either side, against which lever followers operated short valve actuating pushrods that were parallel in one plane to the valves, set at a 90-degree included angle in the hemispherical cylinder head combustion chamber. The pushrods were very short and therefore light and strong.
The 300 Bicilindra offered a claimed 20 hp at 8000 rpm, and the bike ran up to 170 km/h
The distributor is vertically mounted behind the cylinders, as per the Rondine. An electric starter is incorporated and the Earles fork is specific to this bike.
Official 1955 figures (which are not thought reliable) were 20 hp at 8000 rpm, 140 kg and 170 km/h top speed. More realistic figures are 18 hp (with 8000 rpm only being obtained in neutral), 171 kg and 140-145 km/h.
After several years work the bike was started and is now in running condition. A 350 cc DOHC racing version was built in 1955 but its 46.5 hp at 12,000 rpm wasn’t an improvement over the existing 350 racer so it was also shelved. It can be seen in the MV Agusta Museum.
The Moto Guzzi Museum, located in an old two storied building that is part of the original factory in Mandello del Lario, is an “old school” affair – and none the worse for that!
The Moto Guzzi Museum in Mandello del Lario
Although not a part of the museum I thought it fitting to start this column with some views of the Carlo Guzzi memorial in the main square of the town.
The Moto Guzzi Museum
The new main entrance to the factory.
The Moto Guzzi Museum entrance
The far better known old entrance gates behind which is the museum building (with the yellow wall).
The old entranceThe 1919 Guzzi-Parodi or ‘G.P.’
The very first Moto Guzzi resides in a glass case. The Guzzi-Parodi (or G.P.) was named after Carlo Guzzi and Giorgio Parodi and was completed in 1920. The horizontal 500 cc single featured a SOHC, twin spark plugs and an impressive (for the time) lubrication system. Despite a low compression ratio of 3.5:1 it produced 12 hp and was capable of 100 km/h.
The Moto Guzzi Normale
The first production model was the Normale which was built from 1921-1924. While similar to the “G.P.” it had a simplified two-valve head with side inlet and overhead exhaust. Power was 8 hp at 3200 rpm. The Normale weighed in at 130 kg and had a top speed of 85 km/h, well down on the G.P.
Moto Guzzi Museum
The museum consists of a number of long rooms with bikes lining both sides.
Moto Guzzi 500 cc Corsa C4V
The bike on which Guido Mentasti won the Championship of Europe in 1924. The C4V saw the return to a 4-valve head and proved to be very successful. Power output was 22 hp at 5500 rpm, with a weight of 130 kg and top speed maxed out at 140 km/h.
1932 Moto Guzzi 500 cc Tre Cilindri
The only surviving example of the 500cc Tre Cilindri of 1932. Derived from the 1931 500cc four-cylinder race bike, the Tre Cilindri was a highly advanced touring bike for the time, offering 25 hp and a top speed of 130 km/h, but the high price, 169 kg weight and average performance saw it discontinued after only one year.
The Moto Guzzi Alce (Moose) was the vehicle of choice for the Italian army in WWII
Based on the earlier military GT 20, the Alce (Moose) was the main motorcycle of the Italian Army during WW II and was also produced as a three-wheeled truck – the Trialce. One variant was the Cicogna (Stork) seen here. Possibly intended for export to Finland it is fitted with skis. This example carries a copper front guard extension (in place of the normal rubber one) that lists the details of the mountains it has climbed.
250 Compressor with Guzzi Cozette supercharger
The 250 Compressor used a Guzzi built Cozette supercharger and was mainly used for record breaking over a period of many years – 1938 until 1952.
In response to the supercharged Gilera, BMW and NSU race bikes, Guzzi developed this 500cc supercharged triple during 1939. It only raced the once, at Genoa in May 1940 where it retired. The two-valve motor was inclined at 45º and used a 120º crankshaft, while power was 65 hp at 8000 rpm. The bike weighed in at 175 kg and was capable of a top speed of 230 km/h.
Test bed development motors
On the left a water-cooled version of the 120º 500 cc V-twin and on the right a supercharged and fuel-injected 500 cc single.
A recreation of Carlo Guzzi’s office
It is a little known fact that Carlo did not have any financial interest in the company that bore his name. Instead he was paid a royalty on each bike produced.
1949 250cc Gamalunghino – Power was 25 hp at 8000 rpm, weighing 122 kg and topped out at 180 km/h
The 1949 250 cc Gamalunghino (Little long-leg) was basically the pre-war Albatros fitted with the leading link front suspension and brake from the 500 cc Gambalunga. It proved to be a very successful combination, winning the first GP it was entered in – the IoM TT.
Moto Guzzi 250 cc Bicilindrica, designed for supercharging, but in normal trim made 25 hp, weighed 125 kg and did 170 km/h
Originally designed to use supercharging, the 250 cc Bicilindrica’s development coincided with the banning of forced induction in 1946, so when it appeared the following year with a normally aspirated motor it was already a compromised bike.
This 1948 machine is the second (and final) bike built. Despite showing some promise, leading the 1948 Lightweight TT at the IoM, development was abandoned after Omobono Tenni was killed while testing one later in the year.
1955 350 cc World Championship winning bike, you can see performance figures on the placard
Guzzi 350s won every round that season with Bill Lomas taking the title with four victories. Duillio Agostini, Dickie Dale and Ken Kavanagh won the others.
A Zigolo prototype
A prototype for a modernised version of the Zigolo, which was produced from 1953 until 1965.
1947 500 cc Biclindrica with Elektron heads and barrels, power was 44 hp at 7000 rpm, top speed 180 km/h
The distinctive 120º 500 cc Biclindrica first appeared in 1933 and was campaigned until 1951. This 1947 version is basically the same as the pre war model, apart from the heads and barrels being cast from Elektron, not iron.
1958 prototype 110 cc 2-strokes
A line up of 1958 prototype 110 cc two-stroke bikes.
Guzzi scooter prototypes
On the left the three-wheeled Tre Ruote of 1960. On the right a 160 cc two-stroke powered machine.
A 1957 prototype for a 350 cc military bikeAgricultural machinery
Produced from 1963-66 the 486 cc four-stroke motors made 10 hp, had three forward and three reverse gears and a top speed of 13 km/h.
Prototype twin cylinder 125 BiDingo two-stroke
The prototype twin cylinder 125 BiDingo two-stroke was shown in 1971 but was not developed. It was based on the twin cylinder 50 cc prototype (the Ghez) that was displayed at the Milan Show in 1969.
Moto Guzzi Cross 50 cc two-strokes
Two Cross 50 cc two-strokes. The silver bike is a 1977 model. Both were of Benelli origin.
Benelli motorcycles to be sold as badge engineered Guzzis
The first of the Benelli motorcycles to be sold as badge engineered Guzzis (a De Tomaso directive) was the 250TS, which was produced from 1973 to 1983. This Benelli 2C clone differed only in minor details such as the chrome cylinder bores and slightly larger carburettors. This a post 1975 model as evidenced by the Brembo disc brake (earlier models used a drum brake) and electronic ignition.
1986 750 cc Paris-Dakar works bike, producing 62 hp at 7100 rpm, with a top speed of 170 km/h
The 1986 750 cc Paris-Dakar works bike (no.1 of two). These used modified four-valve V75 motors in a chassis based on the earlier 650 cc Baja racers.
1979 125 2C 4T (left)
A 1979 125 2C 4T. This 125cc parallel-twin used half of the 254 four cylinder’s engine, in the same frame and with the same running gear, and produced 16 hp at 10,600 rpm. Weight was 110 kg, while top speed reached 130 km/h.
Moto Guzzi 650 cc Baja TTC
The final 650 cc Baja TTC (of 17 constructed over a two year period beginning in 1984). They were based on the V65 TT and competed in many rallies in Europe and Africa.
The final Benelli-based Guzzi
The final Benelli-based Guzzi was the 125TT that was first shown in 1983 but only produced from 1985 to 1988. It featured a mono-shock rear suspension, 35 mm Marzocchi forks, automatic oil injection, reed-valves and a six-speed gearbox.
1987 V35 Falco prototype
The 1987 V35 Falco prototype ran a 350 cc motor using DOHC four-valve heads and produced 40 hp at 8800 rpm. The project did not make production, but weighed 179 and boasted a top speed of 175 km/h.
Moto Guzzi V35 Florida
The V35 Florida was loosely based on the earlier Custom and was introduced in 1986 (along with a V65 version). Changes included longer and larger diameter front forks, different rear shocks and new instruments. The 350 cc motor had revised bore/stroke measurements so the heads from the V50 could be used and power was 39 hp at 8400 rpm. The bike weighed 170 kg and had a top speed of 148 km/h.
A 1000 cc Daytona signed by Dr John WittnerA 1957 500 cc V8 and motor742 cc racer
This 742 cc bike was used at Monza in June 1969 to brake three world records (the one hour, 100 km and 1000 km) in the 750 cc class (a second bike of 757 cc was used for the 1000 cc records).
Both bikes set further records in October with this 742 cc machine raising the 12 hour average speed to 179.55 km/h. Both bikes made around 68 hp at 6500 rpm and were significantly lightened to 158 kg. A 29 litre fuel tank was fitted. Top speed was 230 km/h.
Moto Guzzi 65 cc Guzzino
This 65 cc Guzzino based bike set 24 World Records at the Montlhery Circuit in France in September 1950.
The Moto Guzzi Museum in Mandello del Lario
The Moto Guzzi Museum in Mandello del Lario
The Moto Guzzi Museum entrance
The Moto Guzzi Museum entrance
Moto Guzzi Museum
A 1957 500cc V8 and motor
A 1957 500cc V8 and motor
A 1957 500cc V8 and motor
The 742 cc racer
Moto Guzzi 65 cc Guzzino
742 cc racer
A 1957 500cc V8 and motor
Moto Guzzi Museum
A 1000cc Daytona signed by Dr John Wittner
Moto Guzzi V35 Florida
1987 V35 Falco prototype
The final Benelli-based Guzzi
Moto Guzzi Museum
Moto Guzzi 650cc Baja TTC
1986 750cc Paris-Dakar works bike
1979 125 2C 4T (left)
1986 750cc Paris-Dakar works bike
Benelli motorcycles to be sold as badge engineered Guzzis
Moto Guzzi Cross 50 cc two-strokes
Prototype twin cylinder 125 BiDingo two-stroke
Prototype twin cylinder 125 BiDingo two-stroke
Agricultural machinery
A 1957 prototype for a 350cc military bike.
Guzzi scooter prototypes
Guzzi scooter prototypes
1958 prototype 110 cc 2-strokes
1947 500 cc Biclindrica with Elektron heads and barrels
A Zigolo prototype
The Moto Guzzi Museum in Mandello del Lario
Moto Guzzi Museum
1955 350cc World Championship winning bike
Moto Guzzi 250 cc Bicilindrica
1949 250cc Gamalunghino
A recreation of Carlo Guzzi’s office
Moto Guzzi Museum
Test bed development motors
250 Compressor with Guzzi Cozette supercharger
250 Compressor with Guzzi Cozette supercharger
250 Compressor with Guzzi Cozette supercharger
The Moto Guzzi Alce (Moose) was the main
1932 Moto Guzzi 500 cc Tre Cilindri
Moto Guzzi 500cc Corsa C4V – Image Phil Aynsley
Moto Guzzi Museum
Moto Guzzi Normale – Image Phil Aynsley
The old entrance
The Moto Guzzi Museum
The Moto Guzzi Museum in Mandello del Lario – Image Phil Aynsley
This is a rather historical bike. Suzuki withdrew from GP competition in 1967, but returned in a limited way with the introduction of the XR05, which was based on the 500 cc Cobra/Titan road bike.
Seeley Suzuki TR500
This modified motor was fitted with a ‘featherbed’ inspired frame and first raced at Daytona in 1968, with Ron Grant placing fourth, and Mitsuo Itoh ninth. Power output was 63.5 horsepower.
It wasn’t until 1971 that the XR05 was officially entered in the 500cc World Championship. Riders Keith Turner, Rob Bron and Jack Findlay finished the season in second, third and fifth places respectively. Findlay’s victory in the Ulster GP was Suzuki’s first in the 500cc class as well as the first win by a two-stroke.
The XR05 was good for 63.5 hp
Despite this success, the bike’s handling left a lot to be desired so famed chassis builder Colin Seeley was commissioned by Suzuki Team Manager Rex White to construct a frame to house the XR05 motor.
A certain Barry Sheene was to be the rider. This prototype frame was made from 1 1/8th Reynolds 531 tubing, bronze welded and had a long 55.5 inch wheelbase.
Seeley Suzuki TR500
Sheene reported it was the best handling bike he had ever ridden and proceeded to win the British Championship on it.
The bike seen here is one of the two bikes supplied by Seeley to Barry and has been restored to circa 1973 specifications. Barry sold it to his friend Dave Goddard who in turn sold it to the current owner in 2010.
Both Colin Seeley and Paul Smart have confirmed its history. Suzuki records show that the engine (TR500-100061) was one of the two supplied to Frank Sheene, Barry’s father.
Colin Seeley was commissioned by Suzuki Team Manager Rex White to construct the frame
Retail versions of the Seely frame, a full rolling chassis, were soon made and available for £350. A new road motor cost £250 and could be tuned as much as the owner could afford.
Competitive 500 cc GP racing was suddenly affordable!
The design was a success so in 1962 a second frame was constructed to house a 350cc motor. 
A third frame was then fabricated for Trevor Barnes who then spent many years racing and developing the bike seen here.
The motor is a 350 cc race unit which was greatly modified by Barnes with many internal improvements including a twin-plug ignition.
Ken Sprayson was generally involved in some way or another with pretty much every frame design used in the British motorcycle industry throughout the 1960s and 1970s. It was Sprayson who fabricated the first ever production Norton Featherbed frame from the designs of Rex McCandless for the Manx Norton. 
He also had a special connection to the Isle of Man TT and worked on frame designs with the likes of Geoff Duke, Mike Hailwood and John Surtees.
Sprayson even had a hand in the design and build of the land speed record holding Project Thrust II jet car driven by Richard Noble to a top speed of 1047 km/h. And that only touches on a sliver from his catalogue of works, almost all of which were successful.
