SUZUKI TM400 CYCLONE - The most dangerous bike ever built?
THE MOST DANGEROUS DIRT BIKE EVER BUILT?
Nov. 01, 2005
EXAMINING THE LEGEND
In 1971, with a great deal of fanfare and hoopla, Suzuki introduced the TM-400 Cyclone motocross bike.hoopla! The press affair was held on a Warner Studios lot and Captain Kirk himself was the celebrity who worked the microphone for the starry-eyed media.
William Shatner stood up there, without a Star Trek uniform, I must sadly report, and told the gathered faithful about the brand new line of bikes from Suzuki. Being a Star Trek fan at the time, I believed just about everything he said. After all, wasn't this the man who kicked Klingon butt?
After a seemingly endless line of street and dual-purpose bikes, the "secret" new MX bike was rolled out by a pair of pneumatic blonde models. We all oooohed and aaaahed at the awesome-looking motorcycle. The damned thing had a truly impressive appearance, with incredible detailing. It was orange in color, with a flat-black finned motor and a sinuous expansion chamber that snaked around the chassis.
I simply HAD TO SIT ON THE BIKE and see what it felt like. Everything was right where it should be, and I clicked the throttle open and closed enough times to satisfy some weird primeval urge.Wow!If looks would determine a winner, Suzuki would have been handed the trophy on the spot.
The specs on the TM-400 Cyclone (cool name!) made your mouth water if you were a dirt bike nut:
Five speed box
230 pounds weight
40 horsepower at 6,000 rpm
P.E.I. Electronic ignition
Oil injection (no more mixing oil and gas!)
Nice long telescopic forks up front
Shocks that appeared serious at the rear end
Real aggressive knobbys wrapped around aluminum rims
Slim, trim feel through the mid-section
Big modern Mikuni carb
Brakes that worked
Since Suzuki had been kicking butt on the World MX scene with Roger DeCoster and Joel Robert on the exotic RH Suzuki works bikes, we expected that the TM-400 would have a lot of that technology built in.
Captain Kirk assured us that the TM-400 was the closest thing to a factory works bike that money could buy, and was a machine for "Experts" only.Since the bar was now open and the journalists were swilling, we all believed him.
It was a fewmonths before I got my chance to test one of the new Cyclones. Suzuki made sure, naturally, that the "friendly" magazines got the bike first, to be assured of good tests that could be used in ads.
The Cyclone fired on the second kick, and snarled to life with an ear-crackling sound puffing from its open expansion chamber.Yup, back in 1971, racing bikes were sold without mufflers of any sort.For sure, at least 40 screaming horses were inside that impressive flat-black motor, and the sound from the stinger let you know.
My first trip through the gears was across a flat, smooth area, and at this point, I was convinced this was the finest race bike ever built.The power ripped!While there wasn't much torque down low, the engine hit brutally hard at mid-range and then literally jumped to peak revs.
It was hitting a light switch, rather than rolling on a throttle.
By the time I had put in two laps on the motocross track, I knew something was dreadfully wrong with either me, or the Suzuki. Whenever I tried to accelerate smoothly out of a bumpy corner, that staggering mid-range would hit and the rear end of the bike would lurch outward. On the short smooth straights, the Cyclone was all you could want, as it pulled hard and clean, and would slow down with authority, as the brakes were far superior to the typical European stuff that I rode at the time.
After 20 minutes of riding, I was drenched in sweat and my hands and forearms were horribly cramped. The bike had scared me badly. Was it me? "Hey, who wants to ride this thing?"
The testers ? all expert level riders ? fought over who got the saddle next.Al Wurtzel, a very fast desert racer, won the coin toss and went out on the course.Ten minutes later, he came in, shaking. "This thing is dangerous! Here, somebody else give it a try."
By the end of the afternoon, all of the test riders, from Novice (me) to Pro, agreed that the all-new, technology-inspired Suzuki TM-400 Cyclone was the worst pile that had ever come out of Japan. If you rode it cautiously, a 125 could beat you around the track. If you rode it aggressively, chances are you would get spit off.
When the TM-400 hit a bump while under power, there was no telling what it would do.Those spiffy forks were as bad as everything else from Japan at that time, and the shocks were beyond grim. Later, when we put the shocks on a shock dyno, we found out that the damping curve was 50/50 (compression/rebound), about the same as your family car.
The frame geometry was flawed, and there was a huge amount of flex both in the frame and the swingarm. When riders tried to turn the Cyclone quickly, the front end would either push badly, or the bike would try to stand up when power was applied.
Amazingly, the bike sold well and you started seeing the orange beasts showing up on MX and desert tracks around the country. People believed all the ads, the bike did look great, and the price was right. Under a thousand bucks for all the power you could ever want.
And very soon after that, the word started getting out: this bike was hurting people!Riders were getting pitched off in corners like so many off-balance frisbees. All those bright orange paint jobs started getting chewed up from slithering and lurid slides, with and without riders aboard.Suzuki owners were limping around, or worse, sporting plaster.
A small industry quickly developed trying to make the bike work.The reasoning was that the bike was so good, there was so much stuff there, that it just had to be some little quirks to be worked out. They put Koni shocks on the rear end and that helped some.Forks were diddled with, but the smart guys gave up with the KYBs and opted for proven Spanish forks.
Frame kits blossomed up all over the place, some simple and some so complex they defied belief. Heavy flywheels were bolted to "smooth out the power" and that also helped some. But the bike remained hard to ride and kept biting riders.Eventually, complete frames were offered, that housed the fierce motor in a chassis with proven geometry.
I was doing my own experimenting with the TM-400 at that time, and stumbled over the real reason the bike was such a brute to ride.The P.E.I. system was the real culprit. It was designed to have the ignition retard for easy starting, and to advance at a certain rpm range for maximum performance.
Somewhere around 4000 rpm, the electronic ignition would go from a mild retard mode, to FULL ADVANCE, with no graduation at all. Bang! The proverbial light switch. What made this problem even more pronounced, was that the "jump" never happened at the same rpm twice in a row. When it was cold, it might hit earlier.As the engine warmed up, it might jump 200 or 300 rpm later. But you could never predict exactly when.
The cure for the crazy power band was so simple that it made people want to bang their heads against a wall: simply replace the modern high-tech P.E.I. system with an old-style points/mag setup. The unit from a TS-400 "enduro" model was a bolt-on cure.
Suzuki never corrected the problem until 1975. Oh, sure, they painted it yellow and gave it Bold New Graphics each year, but the heart of the beast remained intact. The 1975 bike wasn't all that bad, but people weren't buying it anymore. Memories are hard to forget.
It took a completely new bike, the RM that appeared in 1976, to erase those memories.
But for those who still limp from their days with the TM-400 Cyclone, well, they wince whenever they see one of those orange beasts from the past.