Suzuki Tm400
SUZUKI TM400
As yet, still untamed.
Cycle World Road Test
REPUTATIONS ARE funny things. Good ones take years to come by, yet can be destroyed in a minute. Bad ones are earned almost instantaneously, but require years to overcome. The Suzuki TM400 has a bad reputation. Not only has it been said to be a poor motorcycle for its intended use, motocross, but it is the brunt of many motorcycle jokes. Even Suzuki owners readily admit that their 400s aren’t really right. It isn’t uncommon to see a pickup truck with a couple of TMs in the back and a bumper sticker on the truck which reads something like, “Support zero population, ride a Suzuki 400.”
The last Suzuki 400 that CYCLE WORLD tested was the original oversprung, heart-in-the-throat orange tanker. It was as bad as bad can be. It was evil. Staffers almost refused to ride it for evaluation. We’d heard that since then the TM400 has been highly improved. The radical power had been toned down and the chassis didn’t flex as much. Also, the suspension had been ironed out. After riding the TM125 last month for our four-way 125 comparison test, and realizing that Suzuki could indeed build a decent-handling motorcycle, we decided to see exactly what they had done to the 400.
Is the 1974 Suzuki TM400 an improved machine? Undeniably so. The quick, almost wicked, power is still there, although more controllable. The large black engine puts out gobs of power. At moderate trailing speeds it isn’t too difficult to control. Easy? No. But not too difficult.
The transmission is right for motocross. A tall first gear leads into four more closely-spaced ratios that keep the engine in its more efficient range. Swift in operation, the left-sideoperated gearbox gave the rider a sense of in-gear security at all times. Neutral was easy to miss though, since it requires the slightest pressure to locate. Through the thickness of a motocross boot, the snick from either first or second to neutral could not be felt.
Although you almost have to have five speeds in a transmission to successfully market an off-road machine these days (the exception being Maico), the Suzuki could get away with a four-speed. The powerband of the engine is so wide that you generally have a choice of two gears through every turn, either of which will take you through swiftly.
Although it could pull well at very low rpm, the TM lacks sufficient flywheel to make such traversing enjoyable. It kicks and bucks and vibrates mercilessly when forced to perform in this manner. This means that for tight woodsy riding, the Suzook is not the bike to be on. Keep the Rs up a little and it feels a whole lot healthier.
The bright yellow beast is not a bad-handling motorcycle if you remember to ride it swiftly, but not fast. It lands off jumps with considerable plushness and can be pushed through ^et of whoopers at a reasonable pace. The secret here is in throttle hand. Give the TM just enough rope to get it through the particular section of terrain and no more.
If you feed it all the gas you can, the horsepower makes the bike do all sorts of hairy things. It torques the frame back and forth as the wheel contacts, leaves and then makes fresh contact with the ground. The rear end starts to cut a swath that grows in ferocity until the forks hit one stop and then the other. Before you know it. you’re reduced to spectator status.
Restarting the Suzuki after a getoff won’t be as frustrating as starting one cold. The kickstarter is long to provide you with enough leverage to get the piston moving despite its size and high compression ratio. But be warned. The TM likes to kick back and kick back hard. It won’t spit you over the bars like some of the old thumpers would, but it’ll leave your ankle throbbing and you’ll have to resort to push starting it.
The Mikuni carburetor that works so well when the engine is running, doesn’t help cold starting much. Depressing the choke, the rider swings the starter out and begins kicking. If he’s lucky it will light up on aboùt the fifth or sixth kick. If not, he’ll be too tired from kicking to do much riding once he gets it running.
Part of the starting problem comes from the previouslymentioned lack of flywheel in the engine. When the kicking motion has terminated at the bottom of the kickstarter’s arc, the engine stops rotating. With a heavier flywheel in there, the crank might spin over once or twice more and fire. But with an increase in flywheel weight comes an increase in the severity of the kickback force. Therefore, we feel that the TM could also use an in-the-barrel compression release a la Maico, to facilitate starting.
The type of tracks that the TM likes are smooth ones with a good-traction surface. This last item is most essential because the 400 comes fitted with the same shoddy tires as the 125 from last month’s comparison test. The brutal power breaks the rear wheel loose with the slightest over-throttling, while the front one can no more hold a line through a corner than a 250 Elsinore can. A pair of Metzeler or Trelleborg knobbies would be a great help in cornering and acceleration.
The TM comes with some desirable and some not-so-desirable items. The PEI (pointless electronic ignition) and the oil injection system are great for the novice-type rider who will more than likely find himself the owner of a TM. Never having to worry about the points, because there are none, and not having to figure out and mix oil in a gas can every time he wants to go riding, will greatly add to his pleasure.
But the grips, non-spring-loaded footpegs and the brakes will bother him tremendously. The grips are easy to replace. The footpegs a little more difficult, since a spring arrangement has to be fabricated and attached to keep the pegs from folding and staying folded.
As for the brakes, the rear one is too sensitive. It can be all too easily locked up and the engine subsequently stalled. The danger here is that the bike immediately begins to skid. Pulling in the clutch while sliding in this manner can mean a high-side getoff.
Chamfering the brake linings in the rear to reduce the actual amount of brake shoe surface area making contact with the brake drum is the answer. Up front, a heavier, stretch-resistant cable will give the rider more “feel” and improve the performance of the brake itself.
We asked if the TM400 was an improved machine. The answer was yes. But is the TM400 a competitive motocrosser? No way. While the power is there, getting it successfully to the ground through a combination of chassis strength, smoothness of power, and choice of tires, is altogether too difficult. The TM hops around like a pogo stick when you try to push it real hard.
It is very scary to ride a machine under such circumstances and the drain on one’s intestinal fortitude is exhausting. The brutal surges of power are only of use if the machine is pointed in the desired direction. Unfortunately, with the TM’s flexing swinging arm and less-than-adequate shock absorbers, maintaining the desired line is very difficult, if not impossible, at racing speeds. When the rear wheel makes contact with the ground, you are rocketed off in whatever direction you’re pointing. And it’s usually pointing in the direction of trouble.
What, then, is the Suzuki TM400 good for? It is good for playing around on. For trailriding through wide-open spaces. It is good for an occasional blast around a motocross course if Discretion is driving. It is also inexpensive, economical to operate, easy to service, and very reliable (starting aside).
If you don’t have a lot of money to spend, but you know you want a powerful machine, and you have no visions of banging handlebars with the local aces on Sundays, then consider the TM400. But if your mouth waters, your right hand begins to twitch, and your eyeballs bulge when you hear the word “motocross,” buy something else. It’ll keep your insurance rates down.
The Suzuki is nCdably lacking in a few design areas that we mentioned in the test. However, several after-market manufacturers market items that are designed to not only overcome production shortcuts, but that actually improve the TM400 to the point of making it a competitive mount. For more information, read the next article.
SUZUKI
TM400
$1285
