The SUZUKI Racing Motorcycle 50cc models 1960—1968

The golden period for the 50cc bikes was in the sixties when Suzuki and Honda threw the full weight of their technology into developing these pocket rockets. The two stroke Suzuki and the four stroke Honda battled for supremacy. By the time the governing body called an end to the category the top 50s were producing 360bhp per litre, revving to 22,500rpm and using 14 speed gearboxes.

In the year of 1960, Suzuki who had been making motorcycles for some years, decided to apply their knowledge to the racing track and develop a racing 50cc motorcycle.  This followed Honda's lead and as it was proven that to sell to the World, you needed to advertise success to the World.  As a result Suzuki went Grand Prix racing in Europe. The first bikes were very underpowered and the were bested by the Europeans and Honda.  This situation continued until the defection of Ernst Degner from East Germany and the MZ factory, but that is another story.

Suzuki enter a motorcycle team into Grands Prix racing under the manufacturing name Colleda. This was the 125cc RT60 with riders Toshio Matsumoto, Michio Ichino and Ray Fay.  They had little success with their riders being placed 15th, 16th, and 18th in the 1960 Isle of Man TT races.

Still, 1961 proved to be an important year for the Suzuki racing team. It was later during this year that the MZ rider Ernst Degner defected from East Germany. The Suzuki team was in desperate need of help in improving their machines and they negotiated with Degner, assisting him in his defection, to help Suzuki develop their engines.  

Degner was a brilliant engineer as well as a competent rider. During the winter of 1961, early 1962 Degner helped Suzuki to develop a new generation of Suzuki racing machines using the technology that he brought with him from Walter Kadden and the MZ factory. With this advantage he developed the RM62 (50cc), which won Suzuki’s first motorcycle Grand Prix at the Isle of Man TT in 1962, ridden by Degner himself. 

Suzuki RM62 - 1962

Engine type: Air-cooled 49.64 cc single cylinder rotary valve 2-stroke. 8 bhp/ 10.500 rpm.
Bore x stroke: 40.0 x 39.5 mm
Carburettor type: Mikuni 22mm
Compression ratio: 9:1
Top speed: 90 mph
Clutch type: Dry multiple plates
Transmission: 8 speeds
Tyres: 2.00-18 / 2.25-18
Brake type (front): 2 drums, 1 cam
Brake type (rear): 1 drum, 1 cam

The general layout of the engine - gearbox unit is shown in the large cutaway drawing below; You can see the use of a supplementary transfer port opposite to exhaust port, that registers with a window in the piston skirt. The train of moving parts is sketched in the second picture below and shows on the nearside end of the crankshaft the rotary disc valve and on the offside the drive to the eight-speed gear cluster.

				Degner in the 1962 50cc TT
			Jacky Ickx on a RM62	A Picture of Degner RM62 and Taveri Honda

Suzuki RM63 - 1963

But it was in 1963 during the 50cc race that the real history was made, when  Mitsuo Itoh, the eighth-placed starter, took the chequered flag to become the first Japanese rider to win a race at the Isle of Man TT when he claimed the 50cc Ultra-Lightweight TT on the RM63. He remains the only Japanese rider to have ever won an Isle of Man TT race. Itoh won two Grand Prix races during his career. Mitsuo Itoh stayed with Suzuki for most of his racing career

The 50cc Suzuki RM63 for 1963 was just an update on the previous year’s machine with a revised engine and frame. The The barrel was now reversed and the exhaust exited from the rear.  the carburettor had been changed for a 24mm. As a result of these changes the engine produced a further 3 bhp and the speed increased by 3.2 mph. To better manage this increase the 1963 gearbox had been upgraded to a 9 speed version.

Engine type: Air-cooled 49.64 cc single cylinder rotary valve 2-stroke. 11 bhp/ 13.000 rpm.
Bore x stroke: 40.0 x 39.5 mm
Carburettor type: Mikuni 24mm
Compression ratio: 8.8:1
Top speed: 93.2 mph
Clutch type: Dry multiple plates
Transmission: 9 gears
Tyres: 2.00-18 / 2.25-18
Brake type (front): 1 drum, 2 cam
Brake type (rear): 1 drum, 1 cam

		Anderson-Itoh-Anscheidt	Itoh-Morishita-Anderson-Ichino-Schneider-Degner

Mitsuo Ito has had many titles during his career with Suzuki including development engineer, test rider and Suzuki’s top racing Chief worldwide in the mid-seventies. However, his greatest accomplishment was to win a race at the Isle of Man TT. This he achieved when he won, in 1963, the 50cc Tourist Trophy race in the Isle of Man on the re vamped Suzuki RM63. Ito put in a barnstorming ride to retain Suzuki’s Ultra Lightweight TT title, becoming the first, and so far only, Japanese TT winner.

Suzuki RM64 - 1964

By 1964 in the 50cc class, Anderson and Suzuki were invincible.  The machines were reliable and fast and Anderson swept to his third world title with wins at Daytona, France, Finland and the Isle of Man. He also finished second at Barcelona and third at Spa in Belgium to complete a very successful season. One member of the 50cc Suzuki team during that year was Irishman Tommy Robb riding No.3.

Very little change was seen in the RM64 development as the RM63 was tried and tested.  It remained a single cylinder, rotary valve engine and the cycle parts were nearly the same.

 Suzuki RM64 1964 (Photo - The Ex-Tommy Robb Suzuki RM64)

 Engine type: Air-cooled 49.78 cc single cylinder rotary valve

2-stroke. 12.5 bhp/ 14.000 rpm.
Bore x stroke:41.5 x 36.8  mm
Carburettor type: Mikuni 24mm
Compression ratio: 8.8:1
Top speed: 93.2 mph
Clutch type: Dry multiple plates
Transmission: 9 gears
Tyres: 2.00-18 / 2.25-18
Brake type (front): 1 drum, 2 cam
Brake type (rear): 1 drum, 1 cam

So the main changes to the RM63 during it's development to the RM64 were a change in the bore and stroke of 41.5 x 36.8 mm, for a total capacity of 49.78 cc. Power was given as 12.5 bhp at 14,000 rpm. Compression ratio still 8.8 : 1, nine speed gearbox. Top speed was close to 99.5 mph. Instead of a single-sided, two leading shoe front brake, it had now a double-sided, single leading shoe brake.

Suzuki RK65 - 1965

The evolution of the multi cylinder 50 and square-four engines started immediately after the 1964 Japanese GP in November 1964. Honda, with its twin 50s and square-four larger class engines, had taken the 1964 World Championship from Suzuki.

The RK65 was therefor designed as a twin to compete with the twin 50 of Honda and was therefore able to run at much higher revolutions developing greater power. Water cooling was used for the first time with the 50s, which was carried out as a thermosiphon system. All this yielded a power of 14.5 hp. The power band became narrower and that's why the RK 65 was given ten gears. The frame was also changed: the lower frame tubes expired and this created an open bridge frame. The dolphin shell was now so narrow that a bubble had to be made for a gauze area allowing the carburettor to breath and as previously a hole was incorporated for the clutch. 

Engine type: Liquid-cooled 49.75 cc .Twin Cylinder dual rotating discs valves
2-stroke. 14.4 bhp/ 16.500 rpm.
Bore x stroke: 2 x 32.5 x 30 mm
Carburettor type: Mikuni 18
Compression ratio: 8.6:1
Top speed: 102.526 mph
Clutch type: Dry multiple plates
Transmission: 12/ 10 speed
Rotating drum type box straight cut gears
Tyres: 2.00-18 / 2.25-18
Brake type (front): 1 drum, 2 cam
Brake type (rear): 1 drum, 1 cam

Suzuki RK66 1966 

After the success of Hugh Anderson during 1965 on the first prototype twin the RK65, in 1966 it was Hans-Georg Anscheidt’s turn to explode onto the scene. The German rode the fabulous RK66, the two-cylinder, second prototype capable of reaching 105.633 mph. He confirmed his dominance, with Suzuki in the 50cc category for three years, from 1966 to 1968.

Engine type: Liquid-cooled 49.75 cc Twin Cylinder
Dual rotating discs valves 2-stroke. 
16.5bhp/ 17.000 rpm. 
Bore x stroke: 2 x 32.5 x 30 mm 
Carburettor type: Mikuni 20mm
Compression ratio: 8.6:1 
Top speed: 104.526 mph 
Clutch type: Dry multiple plates 
Transmission: 12 speed
Rotating drum type box straight cut gears
Tyres: 2.00-18 / 2.25-18 
Brake type (front): 1 drum, 2 cam 
Brake type (rear): 1 drum, 1 cam

The type RK-66, delivers 2 mph more than the models RK65 last year. As you see it now 16.5 bhp at 17,000 rpm. The compression ratio is 8.5: 1 and the top speed is 106.876 mph.

At the end of 1966, Honda withdrew from the 50 cc class and there was no competition for the 1967 season. Nevertheless, Suzuki has not been idle, as the riders have the new version of the bike in the RK-67.

Hans G. Anscheidt	The RK66 Engine at the Lexmond Museum	The RK66 Engine at the Lexmond Museum-1	The RK66 Engine at the Lexmond Museum-2	The RK66 Engine at the Lexmond Museum-3	The RK66 Engine at the Lexmond Museum-4
Technical details of the RK66		Isle of Man T.T. 1966	Isle of Man T.T. 1966 Ramsey Hairpin	West German GP Anscheidt RK66 a victory in Hockenheim.	H.G. Anscheidt on the RK66

Suzuki RK67 1967

In 1967 it was even easier for Suzuki to win. Honda withdrew from small-vehicle racing to devote all of its energy to larger motorcycle classes and to Formula 1 automobiles. Anscheidt and Suzuki trounced the competition that year. Suzuki had revised the RK66, which was now the RK67 and it now came with new aerodynamic features such as a raised engine-mounting position, moved by a whole 3 inches. This allowed for a sleeker fairing covering the 41cm wide engine. Carburettors grew 2mm and were still Mikuni, and a mechanical water-pump increased the cooling efficiency. These improvements resulted in a higher top speed and this awesome machine won every single race in that year! 

Engine type: Liquid-cooled 49.75 cc Twin Cylinder
Dual rotating discs valves 2-stroke.
17.5bhp/ 17.250 rpm.
Bore x stroke: 2 x 32.5 x 30 mm
Carburettor type: Mikuni 22mm
Compression ratio: 8.8:1
Top speed: 109.361 mph
Clutch type: Dry multiple plates
Transmission: 14 speed 
Rotating drum type box straight cut gears
Tyres: 2.00-18 / 2.25-18
Brake type (front): 1 drum, 2 cam
Brake type (rear): 1 drum, 1 cam

Mitsuo Itoh

Stuart Graham 1967 T.T.

Anscheidt-RK67 and Lodewijkx-Jamathi 1967

The bikes weighed in at about 50Kg and ran on 2” tyres. These tiny engines with pistons the size of eggcups and gearboxes like jewellery were not easy to ride and needed a lot of skill and technique to get the best from them. To quote Kiwi, "Hugh Anderson, winner of the 50cc titles in ’65 and ’66 “You never had more than 500 revs to play with, so you were constantly monitoring the revs, using the clutch and trying to find another hundred rpm – it was minimal stuff".

"A little made a big difference. I enjoyed riding them because you were mentally active in a different way; you had to work very kindly and sensitively with the engine to allow it to do it’s best. I had bloody great water blisters on my elbows because they were tucked in against the cylinder heads and my calves got burned against the expansion chamber shields. I wrote it all down: change down 12 gears for this corner, 10 for that corner and how soon". Riding the 50s was like riding a pedal bike as momentum was everything. You had to not let the revs drop out of the incredibly narrow power band".

Stuart Graham who won the 1967 TT for Suzuki –“The most important thing was carrying speed, because losing any revs would lose you a lot of time. The twin had power between 17,000 and 17,500rpm so you were playing a tune on the gearbox and keeping tucked in behind the screen to the bitter end.”

"Some riders even wore boots a size too small to cut drag and all were on a permanent diet and being small was essential. Honda only won the title once as they were not willing to get into two-stroke technology. Once Suzuki brought out the twin the Hondas struggled to even stay in it’s slipstream".

The Hondas had a wider power band but needed to be kept between 19,000 and 21,000rpm. To get off the line the riders revved it to 18,000rpm and then feathered in the clutch until it got going. Honda tried everything to go faster and even used bicycle type brakes, which clamped onto the wheel rim, reducing the un-sprung weight. This worked so well that they tried it on the 125cc but the rim got so hot it melted the tyres. Honda withdrew in 1966 and Suzuki followed when the category was restricted to single cylinders with 6 gears and an amazing era was over.

Suzuki RP68 1968

The FIM announced in 1967 that 50cc racing engines would be limited to single cylinder and six transmission speeds. That is why Suzuki's 1968 year's 50cc racer the RP68 never appeared in any race. It was an incredible machine with three cylinders and 19 horsepower. It was ready for racing during 1967, just before the Japan Grand Prix, but Suzuki decided there was no point to race a new machine once and then put it in mothballs.

Engine type: Liquid-cooled 49.87 cc 3 Cylinder in V

Triple rotating discs valves 2-stroke.
19.0bhp/ 19.000 rpm.
Bore x stroke: 3 x 28 x 25 mm
Carburettor type: 3 x Mikuni 20mm
Compression ratio: 8.8:1
Top speed: 200 125 mph
Clutch type: Dry multiple plates
Transmission: 14 speed
Rotating drum type box straight cut gears 
Tyres: 2.00-18 / 2.25-18 
Brake type (front): 1 drum, 2 cam 
Brake type (rear): 1 drum, 1 cam

Suzuki had been worried that Honda might, as rumours had it, come out with a three-cylinder four stroke machine to halt the winning streak that they had with the RK67 and so started developing a water-cooled 50 cc three-cylinder two-stroke engine with rotary inlets. This would be the RP-68, (P for Prototype), to be prepared for any eventuality. 

One cylinder is vertical while the other two make an angle of about 100 degrees forward. The bore is 28 mm, but the different sources disagree about the stroke: 25, 26.5 and 27 mm are mentioned. At 20,000 rpm. 19 bhp is developed and the projectile was expected to run at about 124mph during the coming tests in Japan. With a workable power band of only about 500 rpm. 14 gears would be required for this performance.

 Videos on the Internet - Through You Tube

This first video is put on for the sound of the engine only. The bike is a twin engined racer. Only one 3-cylinder RK68 50cc Suzuki bike ever existed as a race going machine and that one is in a museum. The engine in this replica is a twin RK67.

Further information can be gained from Ray Battersbys', excellent book about the company's racing history ("Team Suzuki").

An RK67 fires up. Viewers comment: "this looks (and sounds) like the 1967 Suzuki 50 That Katayama and Hans George Anscheidt rode in the Diamond Jubilee TT.  14 speed box and revved to 18k but only a 500 rev power band TRICKY".

Japan's Suzuki flew the flag for lightweight and ultra-lightweight two strokes in Grand Prix racing. Along with Yamaha, Suzuki helped to refine the formula developed by Germany's DKW and MZ factories, to the point where ever four stroke diehards like Honda were forced to develop "two-smokers" to stay competitive. Here the Suzuki team prepare their elegant 50cc and 125cc racers for the challenge of the TT Mountain Course. The team consisted of Ernst Degner (a defector from East Germany who carried MZ's disc-valve induction secrets with him), Mitsuo Itoh (who would go on to become the only Japanese rider to date to win an Isle of Man TT, and Michio Ichino.

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