La plus répandue de toute, et celle qui aurait pu m'empêcher de rouler en RG500 !
Est-ce que vous imaginez bien le drame que ça représente... ?
En effet Suzuki n'était pas loin de déposer le bilan avec cette aventure.
En concurrence interne avec la GT750.
La RE5 Suzuki... 1973-76
RE5 et non pas RE500 par pudeur sans doute.
moteur transversal, mono rotor, liquid cooled.
497 (x3) cm³
Le prototype RX[Vous devez être inscrit et connecté pour voir cette image]
Le compteur et le feu arrière cylindriques seront remplacés par ceux de la GT en fin de carrière (au sens trou).[Vous devez être inscrit et connecté pour voir cette image]
En cherchant des images de la version twin rotor de la suzuki indiquée par dga je suis tombé sur cela:
Now the story:
In answer to the Rotary Twin question, here are my notes on the background
history of the RT Program. Though lengthy, it is important information in
understanding the thinking and direction of Suzuki at that time. This is
very good information for the RE-5 historian, enthusiast, and collector.
Because of the great length of this total story, I will break it down into
sections that I will post over a period of a couple of weeks. The following
information is presented in a "you are there" format:
The Rotary Twin (RT) Development Program was a serious "turning point" for
Suzuki that can't be stressed enough. This decision revolves around one
major factor and event that left such an impact on Suzuki that it shook the
foundation of the Rotary Program and the company. It changed their
strategy, course, and scheduled production of the RE-5.
Suzuki's motorcycle engineering policy has always been "design for today
with tomorrow in mind." Thus, there are built-in provisions to accommodate
future developments. Looking at an RE-5, certain things just stand out,
such as an oversized radiator, large oil cooler, twin points, hefty
generator, huge twin ducted air box, big 295mm twin front disk, 3-stage CDI
box, and a monster two-barrel carburetor. These were all for today's single
rotor, but designed for tomorrow's twin.
By early August 1972 Suzuki was well along into their quiet Rotary project,
with 12 single rotor prototype machines going through extensive field and
bench testing. At that same time, engineers had a twin-rotor design off the
drawing boards and were working closely with a second R&D team to make up
two twin Rotary prototypes. However, Suzuki knew that the twin rotor would
be the next generation engine in just a few years and already made
provisions for the twin. But, the single rotor had first priority in
development and funding, and the twin was a second-stage fill in. In the
mean time, daily reports on the 12 prototypes showed that the new, improved,
single-Rotary engine developed by R&D performed very well. But, still at
times, it took some slight tweaking and refining. Suzuki Marketing was
pleased with the reports and requested two RX Rotary prototypes and one cut
away engine from R&D wanting to feature them as part of their Suzuki display
at the upcoming Tokyo Motor Show in October, 1972.
The Tokyo Motor Show is the "granddaddy" of them all. Anyone who is anyone
would have been there. This show gives every manufacturer a worldwide
platform to display their latest line up of motorcycles for the forthcoming
1973 season. It also gives them an opportunity to tease and wet the
appetite of both public and press by showing off prototype and concept
machines. Though marketing had a very good idea, their request for two RX
prototypes and a twin cut away engine was rejected because Suzuki did not
want to tip their Rotary hand yet. Somewhat puzzled and disappointed by the
decision from the top, marketing went ahead without the Rotaries. In
October 1972, they set up a fabulous display of 42 machines for '73,
featuring the GT-750K triple taking center stage. The whole R&D team was at
the show and was excited to see what the competition had to offer for '73.
After making three extensive passes around the sprawling show, they returned
back to the Suzuki display and compared notes. The conclusion was Suzuki
had the best display, a terrific line up of machines, the most people, and
more press coverage than anyone else. As far as their Japanese competition
went, Honda had nothing special to speak of but a few warmed up '72 models.
Kawasaki had a new triple to show off, but ho-hum. Yamaha, who was just
across from the big Suzuki display, had a modest line up of bland looking,
so-so machines. The only thing of mention there was a roped-off, covered
display with a sign that read "special sneak preview unveiling at 12:00."
No one on the R&D team gave it much thought.
At around 11:45 a band of reporters were noticed gathering around the Yamaha
display, which now started to slowly revolve. This seemed interesting
enough, so most of the R&D boys made their way over to Yamaha territory
where the crowed was beginning to grow. One reporter said that he heard
that Yamaha had a new, updated version of their prototype GL-750 4 cylinder,
two-stroke, water-cooled, "fuel injection" model ready for production.
Rumors and gossip were abound with all kinds of speculation. At precisely
12:00 the strobe lights went on and fanfare music started to play. This
hype instantly attracted a large crowd, as people started pouring down all
aisles straight for the Yamaha display. With all eyes affixed to the
covered display, two shapely, smiling models came out and slowly walked
around the covered rotating display a few times and pointed to some unseen
bulges. This increased the mystique another notch and drew the crowd in
closer. The strobe lights stopped, and the overhead and side spot lights
took over and fully illuminated the covered display. The two models stepped
back and clapped their hands loudly. At that moment, all the covers on the
display lifted straight up and disappeared into the ceiling rigging...
unveiling... The new Yamaha RZ-201 Twin Rotor Motorcycle! The crowd
clapped, cheered, oooh and ahhhd. The bike was a beauty. Camera flashes
lit up like a Roman candle. Slowly revolving around, the overhead lights
reflected the rich metal flake cinnamon brown-colored tank, accented by twin
white stripes, with a matching contoured tan leather seat. The lower lights
highlighted the radiator and showed off the triple-plated chrome radiator
guards, twin mufflers, side covers, fenders, and wheel rims. The Yamaha
Twin Rotary was absolutely outstanding and stole the show!
Amiss a barrage of questions and a sea of reporters, the Yamaha rep stepped
up to the podium and explained that the RZ-201 was a water-cooled Rotary
with an oil cooler and had a 662cc twin rotary engine that developed 68hp at
6500 rpm, using two Keihin Cu-carbs. They stated that the twin rotors were
uniquely positioned above a five-speed, tuned, syncro meshed transmission
for better weight distribution, handling, and servicing. The twin rotors
were driven by a triple duplex chain and was lubricated by Yamaha's new CCR
system (Charge Cool Rotor - the fuel/air mixture from the carburetor is
mixed with oil for cooling and lubrication of the twin rotors). The bike
comes with dual front disk brakes, which work independently of each other
for safety purposes. In the event of failure, one brake does not negate the
stopping power of the other. The RZ-201 also comes with another Yamaha
first, a hydraulic rear disk brake system. He went on and on and on and
revealed that Yamaha had been working on this twin for years. It was
considered one of the best kept secrets in the industry. He ended his
dissertation by pointing to the RZ-201, stressing it was a fully working and
operational twin rotary, that was tried and tested, was scheduled for full
production, would be available at all Yamaha dealers by mid February, and
that orders were now being taken.
Well... needless to say, the on looking Suzuki R&D team stood there staring,
stunned, and dumbfounded. For one look at this rotary, they all knew there
was no doubt about it. This sleek-looking Yamaha twin "Roadster" was a real
serious threat and was going to give the Suzuki RX5 single rotor a run for
its money, if not bury it! It was at least two years ahead in technology.
To add a little insult to injury, Yamaha reps spotted the Suzuki R&D team
gawking at the RZ-201 green with envy. They sent the two shapely models
over to give them a gift. The first model handed each a press release
packet, which contained color photos, a factory spec sheet, boiler plate
media coverage copy, promo spots, patches, pencils, pricing sheets, etc.
The second model handed each a cardboard tube that contained a large RZ-201
wall poster, calendar, and special first-day unveiling factory brochure.
And... An RZ-201 order form!
After getting over the initial shock, the R&D Team went back to the Suzuki
display and talked about the RZ-201. Some of the lingering questions that
kept gnawing at them were:
1. This was the best kept secret in the industry.
2. They could not believe it was made at Yamaha, for quiet inside
sources would have tipped them off.
3. The comment "working on it for years" didn't fit. Where? With who?
4. Why did Yamaha bypass the single rotor and go straight to the twin?
5. Suzuki purchased a full MFG license from NSU/Wankel.
6. Honda and Kawasaki purchased an R&D license only (non-MFG).
7. Where and who did the bike testing (bench and track)?
8. How did Yamaha come up with this machine?
The answer to all of these questions is a story in itself for another time.
** Here is the important turning point: **
The following Monday morning after the show a special, top-level executive
meeting was held at Suzuki. They were now faced with the cold fact and
reality that by mid February the RZ-201 would be on the Yamaha showroom
floors first. This translates into a major cut of the early Rotary market
and that Yamaha, with its foot first in the door, would capture at least
minimum 75 percent market share, thus regulating the Suzuki Rotary as a
"Johnny come lately" (catch up). Not only that, but by drawing people into
the dealers to see the advanced RZ-201 would, in turn, increase Yamaha's
other model sales as well.
Armed with this, Suzuki went into a semi panic. It forced them to kick up
their RX program, fast track all Rotary testing, and give priority and
funding to R&D for the twin Rotary. They also pushed up production of their
new RE-5 by a year and a half. This was done despite loud protests by
engineering, R&D, and marketing. They felt that by rushing the project
would create problems down the road. Their protest was noted but was
Between October and early February of 1973, everything was still "fast
track." The two R&D teams were working diligently. The first R&D team
working on the RX project was still ironing out minor kinks in the
single-rotor engine. It attributed some of the problems through outside
parts sourcing. The second R&D RT team put together two twin-Rotary engines
(RT-13 #10013 and RT-14 #10014) and were bench testing them. All eyes were
looking toward mid February when the RZ-201 would hit the Yamaha showrooms.
February passed, and no RZ-201s were to be seen anywhere. Most everyone
figured that they were on their way -- just slow delivery. The first half
of March finds that R&D fitted RT-13 Rotary prototype engine into a test
bed machine using a slightly modified RX frame. Twin testing continued both
on bench with RT-14 and now on the test track with RT-13. Twin information
is somewhat sparse at this time. But notes indicate that, though both
Rotaries ran, problems still persisted with carburetion that had not been
ironed out. RT-13 was running on the test track when the engine blew, due
to seized main shaft bearings from lack of oil and an ongoing problem of
overheating. RT-13's engine was pulled, and R&D took it apart for
inspection. It was never reassembled. The second test model using the
RT-14 engine was put into the RT-13 frame. This was put through extensive
and severe testing. Once again, a few problems kept creeping up. In any
event, Suzuki was confident in the R&D team and felt it was only a matter of
time before the "Twin" was perfected. They sent an encouraging memo to both
R&D teams telling them to keep up the good work and that new improvements in
sealing, metallurgy, coating, carburetion, etc., were coming in shortly from
the expanded NSU/Wankel main information pool. By the end of April, all the
new technology improvements were taken from the pool and were adapted into
the RX single rotor and the RT twin. This cured many of the problems, but
the twin carburetors were still a little tricky at best -- with lingering on
again and off again glitches surfacing. The adaptation of a fiber insulator
block from GM (General Motors) and thicker gasket material from CW (Curtis
Wright) helped out quite a bit.
On May 1, 1973, Yamaha issued a press statement that the RZ-201 would not be
available until mid August due to a minor assembly line teething problem.
Hearing this announcement, both teams were jubilant, for it now bought them
three and a half more months time to work on the engine. And now they were
basically on an even keel with Yamaha, as this brought them to within three
weeks from the next Tokyo Show in September where they could display the
next RX-5 single and the RT-Twin models. They could then go toe to toe
with the RZ-201. While the two R&D teams were jumping for joy, Suzuki
corporate saw the statement as a red flag and did not buy Yahama's story.
They felt there was more to the story than what meets the eye and felt it
was more than an assembly line problem. At this point several rumors
started to circulate:
1. Yamaha's RZ-201 Twin developed major engine problems, and it was
back to the drawing board.
2. Outside source part suppliers for the RZ-201 were running way behind
3. Yamaha really had an assembly line problem and was revamping it for
better production flow.
4. Yamaha was trying to raise funds to manufacture the RZ-201 by taking
pre-production orders (?).
The real "zinger" is:
5. Inside sources claimed that the RZ-201 displayed at the show was a
dummy that did not run and that the high-polished engine and transmission
cases were totally empty.
At this point in time, the RZ-201 falls into limbo and disappears. Over the
next three and a half months, we find the R&D team still working on the RX
single, and the RT-14 twin was still giving them some minor sealing
problems, heating problems, carburetor problems, and timing chain and
transmission problems due to the high torque. R&D pointed the finger at
outside source suppliers due to the "fast tracking" and that their quality
control left a lot to be desired.
By late August there was still no sign of RZ-201 activity anywhere. At this
point and because of reliable source information that the bike was a dummy,
Suzuki corporate discounted the RZ-201 as a false alarm and threat and moved
ahead with the major decision to definitely come out with a twin Rotary.
But, for now and in view of the $90 million+ already spent on the Rotary
project, all the tooling is geared for a single. They felt the best
direction to take at that time was to get the RX-500 out into the motorcycle
main stream to try and corner the Rotary market, capture a lion's share, and
then offer a big twin, RT-10, 1000cc Road Cruiser as a new second model
generation for the '77 season.
In September Suzuki set up another fabulous display at the Tokyo Motor Show
and featured three RX-5s: a burgundy, a two-tone firemist blue, and a
two-tone metal flake green. The bikes were the hit of the show, and Suzuki
followed suit and copied Yamaha's giveaway (cardboard tubes with promotional
items in it - wall calendar, factory spec sheet, radio promos, etc.).
** Per the above link, I have placed some photos of some of the items that
were in that cardboard tube. **
Yamaha had a nice display of bikes, but no RZ-201 nor any mention of it
whatsoever. The bike disappeared. The only other Rotaries at the show
1. Sachs had five pre-mix, air-cooled W-2000 models -- two red tanks
(one with a Sachs name badge on the tank and one with a Hercules name badge
on the tank) that featured a single KC27 engine, one yellow tank (with
Hercules name badge) that featured a KM24 single with a shaft drive using a
BMW transmission. They also had two other W-2000s: a black tank with DKW
badge and a blue tank with a Victoria badge. All these were trade names
used They also displayed an inline, working KM914 "Big Twin" Rotary engine
that was going to be offered the following year as an option (see photos
posted). The only other thing of note was that Sachs had two scantily
clad/risqué models walking around showing off the new W-2000 Rotaries.
However, show officials did not like their attire and politely asked them to
change their clothes (see photo).
2. NTV (Nortorn Triumph Villars) had two twin Rotary prototypes on
display. The first used a Sachs KM24 snowmobile engine (all their R&D did
was make two snowmobile engines together). The other used a Sachs KM914
industrial engine and did the same. These machines looked used and tired.
To move along with our story, the next year R&D continued to refine the RX
engine, now called the RE and the RT Twin. In September 1974, the full
production 1975 RE-5M Rotary made its grand debut at the Tokyo Show. Once
again, it was an instant show stopper. On display was an RE-5 in firemist
red, one in firemist blue, plus and RX-5 burgundy model. Though initial
sales and reserve production blocks showed a very promising future for the
new RE-5, sales started to fall off sharply by March 1975 after the public
and press put it through their own street and track testing and long
endurance runs. Problems surfacing with engine seals, first and second
gear, spark plug, and carburetion were the main complaints. This led to
"quiet recalls" to fix the problems. This fast tracking that R&D
engineering and marketing warned about was now starting to catch up.
Most cycle magazines poked fun at the softball turn signals, rolodex gauges,
and coffee can stop light assembly (all of which did not help the sales of
the RE-5). Suzuki was aware that the Italian space age design was ahead of
its time and was reverting back to a more conventional look. However, since
they were loosing serious money on the RE-5M, they opted to give the RE a
cosmetic face lift by using nearly everything on the GT-750 shelf that would
fit. They would now offer the bike as a 1976 "A" model. With new
improvements and corrections to the engine, plus today's styling, they hoped
this would turn everything around and boost Rotary sales. Suzuki still felt
that the Rotary was going to be the power source for all future motorcycles.
Needless to say, due to financial circumstances, the RT-Twin was put on hold
for 1976. But R&D could continue with their twin prototype and experiments.
In April R&D made some engineering advancements and pulled RT-14 #10014 out
of the frame (the engine seized due a Mikuni #37 oil pump going bad) and
added RT-10 #10050 with rear disk brake assembly in its place. They put it
through more testing. It performed smoothly without a hitch and worked
above everyone's expectations. This all was due in part to the addition of
three new members of the R&D team, who came over from Yamaha and worked
directly on the (now canceled) RZ-201 project. They confirmed it and
removed all doubt. The RZ-201 at the show was not a "dummy" but a fully
operational twin "Rotary Rocket" motorcycle that was scheduled for full
production. With them they brought over inside information, notes and
hands-on twin Rotary experience to their Suzuki RT program.
NOTE: RT-10 #10050 was a combination of the best of both engines -- the RT
and RZ Twins.
The new R&D Team listened to suggestions, tips, and recommendations from
riders, mechanics, and dealers regularly, sifting through the many letters
and faxes pertaining to the complex, time-consuming, and often antiquated
task in servicing the Rotary engine. With this in mind, the new R&D Team
built and tested a revolutionary, advanced, state-of-the-art Twin Rotary
(RT-10051) that was modular in design and had enhanced servicing features
that meant that one no longer had to take apart the entire engine to replace
parts or do repairs. A few of the enhanced service modifications made were
an oil sight glass next to the dip stick, and an identical sight glass was
also added to the clutch cover so you could monitor the level of the
Next, the big clutch cover got a treatment. The "bulge" on the RH side
(185mm - 7-1/2 inches dia.) now had two 6mm allen-head bolts on the face.
By removing the two bolts, the face plate would come off, thus exposing the
complete primary drive gear and clutch assembly, allowing easy replacement
of clutch plates and disks. Also, the timing chain now had a master link.
A removable distributor assembly was added, with a special screw to the
right side that was an alignment provision so you could put a rod through it
to align the timing gear perfectly with the alignment mark on the inside of
the case. The transmission, though it seemed to be part of the complete
unit, was actually separate and could be removed and replaced with a new one
within ten minutes. There was eight different modular assembly features on
this engine, which in essence made it a total breeze to replace almost any
part on it (even by a novice). One of the master features of this engine
was taken from Curtis Wright working with General Motors engineers. On the
top left and right housing assembly, there were two aluminum caps held on by
two 5mm screws. By taking off the caps, which were very similar to the
timing inspection caps, revealed a rotor at 12 o'clock. All one had to do
to change the main seals was push it out one end and insert the new one.
The was reminiscent to the Schick Injector razor blade (push the old one out
and automatically put a new one in its place).
The last Twin R&D made was #10052. This engine was also modular in design.
The only difference was that this was fitted into a shaft drive system. It
was bench tested, performed excellent, and was one step away from being
mounted into a frame that had mag rims. This Twin engine now had four spark
plugs (two for each chamber). This idea was borrowed from Mazda. Then, all
of a sudden and out of no where, R&D received an executive notice from the
front office that the Rotary project was canceled and should come to an
immediate and abrupt halt. Any and all production of the Rotary, including
R&D, should cease immediately. Thus ends the Twin Rotary dream. But the
technical advancements derived from R&D were not in vain, for many of the
ideas and advancements can be found in the GS models.
Epilogue... Though some of the RX and RP prototypes did get away from
Suzuki due to one thing or another, one point is assured -- Suzuki kept all
the blue prints and prototypes of the Twin Rotor models. They still have
them tucked away in their warehouse. Suzuki invested multi millions in
their Rotary dream and envisioned it as the power source of the future.
They were dedicated to that ultimate end.