50cc Racing History from 1953 through to 1983 
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H. L. (Bert) Fruin  -  The Fruin Dartela

I did not know Herbert "Bert" Fruin, although I did come across him at race meetings and other motorcycle venues. He was a keen enthusiast of motorcycle races, especially those where the 125cc and 50cc classes participated. 

Speaking to riders that knew him, it appears that Bert loved the motorcycle and was a 'fingers man'. Always wanting to get his hands on what makes it work. He, like many motorcyclists of the time, would carry out all maintenance work needed on his machine and other peoples and where and if possible make them go faster.

This is no surprise as Bert Fruin was a motor cycle shop proprietor and engineer, operating under the name of H L Fruin Motorcycle. He was born in Hillingdon, a town in Middlesex, England.

An interesting point in connection with Bert’s early road racing experience is that he took part in speedway racing at the Greenford track in Middlesex, in 1929. He was using a belt-drive B.R.S. model Norton! pictured below 

His interest did not stop there and he carried on with the motorcycle business during the coming years until in 1954, when he worked on a new racer and rode his E.M.C.-Puch in the 125cc, class at Isle of Man Tourist Trophy  races, but failed to finish the course, being overtaken by the “Roads Open” car on the final lap. A little more time and he would have crossed the line.

He was again a last lap retirement, on the same EMC-Puch in the 1955 125cc Ultra-Lightweight TT.

Good fortune in T.T. races so far has escaped him. In the 1956 125 c.c. event, he was riding the DOHC twin cylinder engine that he had developed in his workshop, and on his fourth lap, the bike developed engine trouble and he was forced to retire. If it was any consolation to Bert Fruin, he was not the only rider to pack in during that race– in fact, only nine motorcycles finished! Included in the DNF list were CZ, MV Augusta, Mondial and the LCH being a special developed by L C Harfield.   

This enthusiasm was why, in 1957, he started his dream and as a British engineer decided to manufacture his first competition racer under the HL Fruin Motorcycle brand.

This enthusiasm was why, in 1957, he started his dream and decided to manufacture his first competition racer under the H L Fruin Motorcycle brand.

Operating as  an independent engineer 'Bert' constructed a series of technically interesting 'specials' in the 1950s and 1960s, before his 50cc indulgence including the DOHC 125cc twin-cylinder racer and a modular V4/V8 engine. 

In his spare time Bert was a saxophonist, and singer with a band. When interviewed by the TT Special, newspaper (16 June 1954, p.12.) he offered his hobby as "Dance Bands" (motorcycles were his life).

The 'TT' records from 1954 t0 1959. My thanks to Bill Snelling for the use of these pictures from the The FoTTofinder Bikesport Archives. Reachable through TT Race Pics

 Races entered

Bert Fruin (EMC Puch) in the 1954 Ultra Lightweight 125cc TT

Bert Fruin (EMC Puch) 1955 Ultra Lightweight TT

Bert Fruin (EMC Puch) 1955 Ultra Lightweight TT

Bert Fruin (EMC Puch) 1955 Ultra Lightweight TT

Bert Fruin (Fruin Special) 1957 Ultra Lightweight TT

Bert Fruin (Fruin Special) 1959 Ultra Lightweight TT

Bert Fruin (Fruin Special) 1959 Ultra Lightweight TT



 

Also as the proprietor of H L Fruin Motorcycles in Hillingdon, he began competing on his first creation, the Italian Demm Demon-based 50cc two-stroke Dartela racers. In the late 1950s he began racing it on the small circuits of the British Isles and  later at the Isle of Man 50cc TT in 1962 and 1963. unfortunately he retired on both occasions. Bert did enter 3 of this model Dartela in 1962, the other two being ridden by Jock Wright and D. Guy, these also failed to finish.  However Bert  then went into limited production of machines for that class, plus a similar one for sports road use. Picture: (Bert Fruin's Dartela at Silverstone 1958)

Both machines used the Italian DEMM engines, and a tubular frames with conventional suspension. The both models were sold as the "Dartela". (He also built a 200cc Four using Demm top-ends and later NSU Quickly components, which was sold in kit form as a crankcase and set of crankshaft blueprints - more about these bikes further down the page). Picture: The Fruin Dartela, with Bert Fruin at the 1960 50cc Enduro held at the Snetterton Circuit in Norfolk The Rider is R. G. Harris (George) and his co-rider was Jock Wright

The 6 speed, 50cc  “Fruin Dartela” 

Further tuned by Bert, the 50cc Demm engine went into a frame of his own design. Although it fared reasonably well against the ubiquitous ITOMs, the Dartela was handicapped by its three-speed gearbox (the ITOMs had four speeds) so for the inaugural 50cc Isle of Man TT in 1962, Bert produced a longer frame to accommodate an additional Albion two-speed 'overdrive' gearbox (actually a horticultural cultivator box, suitably modified) giving six speeds in total. 

The integral gearbox was operated by a twist-grip on the left handlebar, the overdrive by a foot change on the right. Ridden by Bill Fruin himself, the solitary six-speed Dartela retired with engine trouble on the first lap of the 50cc TT, a race won by Suzuki-mounted Ernst Degner. Bert recorded another 'DNF' at the 1963 TT but it is not known whether he rode the six-speed Dartela on that occasion. Picture: Isle-of-Man-TT-1962-Fruin-Dartela-50cc-Six-Speed-Racing-Motorcycle, The Albion gear unit can be seen, neatly tucked in behind the engine.  Click to see the DEMM page.

One of the three Fruin Dartela racers that was on show in the Murray museum in the Isle of Man 

A production Model racer with Rev counter capability but without the two speed overdrive.

The same production model showing the head steady and a clearer picture of the downdraft carburettor 

This looks like a Fruin rolling chassis but the complete bike was not sold in this condition. The engine is a non standard unit more forward slanting.

The Four Cylinder Fruins

Just two examples of the 200cc, four cylinder, two-strokes were produced by Bert  in 1961. The Fruin bikes were originally sold in kit form but this was short-lived due to the complexity of is design and high cost. With hindsight its not hard to see why. The engine was sold as un-machined castings and the four coil, four breaker electrical system was crude. This restored bike is, though, nothing short of a masterpiece. The first Fruin-built 200cc Four, shown below,  was featured in The Motor Cycle magazine (3rd May 1962 file), which also revealed his plans for future multi-cylinder 'strokers'.







The bike below is the 1965 Fruin 200cc Four-cylinder Racing Motorcycle Frame no. 419220S Engine no. BF2. The engine of this extraordinary motorcycle is again the work of independent engineer H L 'Bert' Fruin. 









Designed to accommodate Demm top-ends and later NSU Quickly components, Bert's four-cylinder engine was sold in kit form as a crankcase and set of crankshaft blueprints at a cost in 1961 of £16. The engine of the machine shown here was built by engineer Mike Smith of Waltham Abbey, Essex around 1965 and uses NSU cylinders and heads. It was fitted with Wal Philips fuel injectors initially and then Dell'Orto carburettors. 

Mike Smith housed the Fruin engine in an MV Augusta rolling chassis fitted with Royal Enfield forks and Gilera hubs. Power reached the ground via a Villiers four-speed close-ratio gearbox. Motor Cycling magazine featured Smith's Fruin Four in its 24th July 1965 edition. The Fruin proved un-competitive in 250 classes so Smith used it mainly for sprinting.

At some time in the 1980s Mike Smith sold the Fruin to Kevin Burton, who in turn passed it on to Tony Milk of New Costessey, Norfolk.

 In 1999 Mark Turner of Track & Classics, Stockport bought the bike from Tony Milk who had advertised it for sale in Old Bike Mart. It is understood that the Fruin was run but never raced by Tony Milk. Mark Turner made a new fuel tank and re-commissioned the Fruin, which was run at his shop in Stockport and again at a classic motorcycle event at Elvington Air Museum. While in Mark Turner's ownership the Fruin was the subject of an article in Classic Bike Guide (March 2000 edition).

Turner then sold the Fruin to a collector, from whom it was purchased by the current owner and restored by Noisy Toys in 2009. Refurbishment included rebuilding the engine and gearbox, repainting the frame and fuel tank, re-plating the brightwork, overhauling the carburettors and float bowls, and rebuilding the wheels. The electrics remain original and un-restored. Following its restoration the Fruin was displayed on the Carole Nash stand at the NEC, Birmingham and also at the Stafford Show.

The 1903 WYATT-MINERVA 331CC MOTOCYCLETTE

Well before involving himself in the racing bikes Bert owned a truly Vintage machine. I include it here to show his previous interest in motorcycles.  My thanks to Bonham's for this information.

• Previously owned by H L 'Bert' Fruin
• It has been in the present family ownership since 1953 and auctioned on the 16th October 2016
• Pioneer Certificate

Although a late comer to bicycle manufacturer, the Belgian Minerva concern was among the first to offer a viable proprietary engine for motorcycles. Nominally of one horsepower, the 211cc unit was designed for attachment ahead of the cycle's front down-tube - a location which became known as the 'Minerva position'

This Minerva-engined machine is badged as a 'Wyatt Minerva', though whether 'Wyatt' refers to the make of bicycle or the shop that assembled the machine is not known. Driving directly by belt, the engine displaces 331cc and has the 'atmospheric' type of inlet valve and a mechanical exhaust valve.  

An older restoration of 'H 338' states that this was previously registered to independent engineer H L 'Bert' Fruin of Hillingdon, Middlesex, constructor of a series of technically interesting 'specials' in the 1950s and 1960s, including a DOHC 125cc twin-cylinder racer and a modular V4/V8 engine. Bert Fruin rode the Wyatt-Minerva on the Pioneer Run at least once, and sold it to Stan Gilks in February 1953 (see documentation on file). The machine was last taxed in April 1966.

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