The Suzuki "Pure Enduro" series of off-road racing motorcycles ran from 1977 through to 1984 in engine displacements from 175cc through 400cc. All engines were case-reed valve, air-cooled, two-stroke and single-cylinder with plain steel bores. Lubrication was provided via 20:1 pre-mix. These were directly related to the Suzuki RM series (Racing Model) range of motocross racers.
Background During the 1970s, Suzuki had become the first Japanese producer to win a World Motocross Championship, and swept many events via the riding of stars such as Joel Robert, Roger DeCoster, Sylvain Geboers, Gaston Rahier and Gerrit Wolsink on their RH and RN series factory racers.Suzuki. Jeff Clew, 1980, Suzuki Two-Strokes. Roy Bacon, 1984,
By 1974 the publicly available TM series (1971–75) of racers failed to reflect the advances of the factory Grand Prix machines in performance and handling.Suzuki. Jeff Clew, 1980, This was recognised and within two years, replaced by the much improved RM Series machines. These became extremely popular. The direct transfer of the works Grand Prix developments into the RM Series combined for major success in the market.Suzuki. Jeff Clew, 1980,
Creation of the PE In the specialised Enduro field, the USA market was dominated by machines by Penton (KTM), Rokon, Husqvarna, Maico, CZ, Can-Am and others. Suzuki saw this as an area in which they could compete. In 1975, Tosh Koyama and T. Shigenoya at US Suzuki asked John Morgan to provide the factory with information about Enduros and Enduro motorcycles. He then met with a group of Suzuki's factory engineers to discuss in detail. Suzuki were also working with Graham Beamish (their UK importer), and in Autumn of 1975,Motor Cycle Mechanics, December 1976Cycle Illustrated, January 1977 undertook to take the upcoming 1977 RM250B motocrosser and add the appropriate engine, lighting and suspension changes to allow this motocross racer to run over short stretches of public roads during enduros. This was a keenly priced, well performing machine for the period. The British Trophy team entered 3 of the new PE250B into the Austrian ISDT of September 1976 and carried off 3 gold medals, despite repeated stops to allow the machines to cool.Motor Cycle Mechanics December 1976REVS, November 1976
The initial 1977 PE250B proved rugged, well made and docile. The engine was effectively the 5-speed RM series motocross engine, with altered gearing, porting and a heavier flywheel, which produced only 28HP but had broader power and outstanding torque. This proved highly competitive and popular in all countries.Cycle Guide, October 1977Cycle, March 1977Dirt Bike, March 1977
Models The following year, 1978, the decision was made to widen the model range and the PE175C was released. This was again based upon an RM Series machine (the RM125) with appropriate alterations. The PE250C continued its development and had many small but effective improvements. The PE175C was built upon the RM125A frame and 6-speed RM125C components, along with the "A" softer suspension. Lighting and speedometer were provided courtesy of TS Trail/street machines. All PE's until the PE175Z had 36mm forks common across each model year with damping and spring-rate changes to suit. This new PE175C was keenly priced and proved immensely popular.Cycle, September 1978
1979 saw detail/evolution changes but nothing ground-breaking on the machines.
1980 saw the further widening of the range, with the introduction of the PE400T. This was unusual in that the 397cc (85mm x 70mm) 5-speed engine was specifically designed for the PE Series and did not leverage the contemporary RM400 motocross engine. The 400 engine was deliberately designed as an enlarged RM250 and including primary kick. This was instigated by John Morgan of Team Suzuki in the USA.Australian Dirt Bike, July/August 1981
It shares mounting points and some components with the PE250 engine. In addition, 1980 saw the introduction of major advancements and refinements carried over from the RM machines, such as the alloy swing-arm, better suspension, many engine improvements and the addition of a superb quick-change rear wheel. This created a very successful range of machines covering the PE175, PE250 and PE400.
1981 saw the 175, 250 and 400 being successful and popular, with limited development. The PE250X had many minor changes, but while changes were still occurring, these were not ground-breaking or major. 1981 was the last full-range year for most countries and with the focus of Suzuki moving to cleaner 4-stroke engines for the majority of their new machines and range. Effectively, 1981 became the peak year.
By 1982, clearly, the PE Series was now seriously lacking on-going development. Suzuki was changing its focus, pulling out of serious enduro competition and the Pure Enduro range was being curtailed. 1982 (model "Z") was the last year where all three models could be purchased and even then the 250 and 400 machines were only available in small numbers, in a small number of countries. (Mainly the UK, Australia, Canada). The larger model Z's (250/400) had a handful of minor changes but could not be described as notable improvements over the previous "X" series machines.
The PE175Z and PE175D however continued to evolve, and took advantage of the new RM125 mono-shock 'Full-Floater' system to produce an outstandingly well-handling enduro machine, albeit with lack of on-going engine development. The PE175D was the "Z" with altered gearing. This meant it was easier for the novice, compared to an "A-Grade" rider, but the PE was now slower and undeveloped in comparison to the 200cc machines becoming available from other manufacturers.Dirt Rider, July 1983
In 1984, the last PE machine was released, the PE175E. This was effectively a run-out of the remaining machines, with minor changes.
There was never a production PE125 machine; though a lightweight (87.5 kg) prototype PE125 was raced by Dwight Rudder on the ISDT team in 1981 at Elba, Italy.
Road legality In various countries the laws mandated that road-registered machines have lights/horn/blinkers/stop lights/mirrors in various permutations. In some countries this led to unusually large rear tail-light assemblies and round red reflex safety reflectors on some models, as Suzuki ensured their compliance with local design rules. All PE's came fitted with effective mufflers, with restrictors and double-walled expansion chambers (with mesh) to meet noise and spark restrictor laws where applicable.
The USA machines usually came standard with a trip-meter and minimal AC lighting, with a speedometer as an option, whereas PE's in Australia and Belgium (for example) had speedometers, stop lights, horn, 6V DC battery and charging system to suit, by law. The UK machines did not have indicators or battery; however these did come with an AC horn. The lighting requirements varied across years and countries, so a PE in the UK, South Africa or France might have substantially different rear tail-lights and mounting assemblies to those in the USA. The French PE's (for example) continued to use the PE250B style headlamp shell, with a parking light and a yellow globe insert, due to local regulations.
Also some countries (UK for example) required an alloy fuel tank rather than plastic, which is almost identical to the PE250B tank, but with altered front mounting-strap tabs. The capacity of the plastic fuel tanks varied from 12litres to 10.6litres on various models, without any obvious visual differences, possibly due to mould thickness. Suzuki usually supplied the PE with one of three different brands of tyre depending on local requirements. The standard tyre was the IRC, however some years and countries saw other brands such as Bridgestone or Dunlop fitted (run at 5-11PSI).
Competition
Suzuki were committed to international enduro racing from 1976 until they pulled out in 1982.
In the UK, Graham Beamish and his staff worked out the characteristics for the ideal enduro machine and sent them to Japan during the winter of 1975. On the other side of the Atlantic Ocean, in 1975 US Suzuki requested John Morgan (who had been campaigning a modified TS250 with great success) to select three additional riders and compete in four National Enduros that year. Then in 1976, they continued to develop the PE250 and competed in a number of events with just one rider, Teddy Worrell, who did quite well. The next year, 1977, was the start of Team Suzuki, which competed in National Enduros and IDSE Qualifiers and the US team went to the ISDT in Czechoslovakia (widely considered one of the toughest ISDT events ever) with three riders comprising Teddy Worrell, Dave Hulse and Bruce Kenny. This left John Morgan and mechanic Aki Goto to address DNF's due to ring seizures on all three machines.Motorcyclist, December 1977
The competition development of the PE drew heavily upon the American test team and the factory put a lot of trust in the development riders and their recommendations - much of which found its way into the production machines. For example, R&D for the first generation PE175 was one task of Drew Smith and Mike Rosso. Herluf Johnson, Ted Worrell and Gus Blakely all played major parts in development. Drew Smith, for example, made most of the pipes for all the Team Suzuki bikes. The team generally used Works Performance shock-absorbers, while working with the major Japanese companies, Kayaba and Showa, trying to develop an improved shock-absorber design.
At the peak there were 16 riders representing Team Suzuki in the US. Some were National Enduro and some were ISDE - some were both.Luke Brennan, personal correspondence with John Morgan and Drew Smith
A selection of well-known enduro racersTeam Suzuki 1980, Booklet published by Suzuki News Bureau, US Suzuki Motor Corp from that period were: British Trophy Team riders Ted Thompson, Ernie Page and Brian Higgins all rode PE250B's to Gold in 1976 (Zeltweg, Austria).Motorcycle Mechanics, December 1976Trail & Track, December 1976 Tom Penton, who scored his sixth ISDT Gold when he competed in his final event (High Chaparral, Sweden) in 1978, riding a factory Suzuki PE175 entry. Don Cichocki, Mike Rosso and Dave Hulse all earned Gold on the new PE175's at Sweden. Gary Edmond attained Gold at Sweden in the 350cc class, riding a special enlarged PE250 - a precursor to the later PE400.Cycle World, January 1979 Jeff Fredette was recruited by Suzuki in 1979 and raced aboard a PE250. He earned gold medals at the 1979, 1980 and 1981 ISDE events in Germany, France and Italy. In 1981 he was also the overall winner of West Virginia's prestigious Blackwater 100. "Diamond" Drew Smith earned gold medals at the 1978 (High Chaparral, Sweden), 1979 (Lager Stegskopf, West Germany) and 1981 (Isola d'Elba, Italy) ISDE's on a PE250. Drew campaigned for most of the 1980 season with a broken wrist! Ray Cosgrove attained Gold in 1979 (West Germany) as a privateer on a PE250. He then joined US Team Suzuki as their PE400 rider. He followed this by earning a silver medal at Brioude, France in 1980.Team Suzuki Rider Profiles 1981, Booklet published by Suzuki News Bureau, US Suzuki Motor Corp Dwight Rudder, Dave Hulse and Mike Rosso each earned a Silver at the 1979 ISDE (Lager Stegskopf, West Germany) on PE175's, while Don Cichocki earned a bronze medal. "Iron Man" Mike Rosso was the top qualifying US 2-day rider in the 175cc division for 1979 and again showed his skill, with Gold on the PE175 at the 1980 ISDE in Brioude, France. Geoff Udy of Australia achieved a Bronze on one of the first PE400's into Europe for the 1980 ISDE.Alex Vercion, personal conversation with Geoff Udy Dwight Rudder also earned a silver medal with the unique PE125 prototype at the (Isola d'Elba, Italy) 1981 ISDE.
Timeline 1977 PE250B initially released.