Suzuki Tm 250
SUZUKI TM 250
CYCLE WORLD ROAD TEST
IT DIDN'T TAKE THE JAPANESE very long to lead the world in the road racing game, and now it appears as though they might do the same in motocross racing.
Japanese scramblers have, in the past, been something of a joke. Too heavy, power in the wrong place, and atrocious handling are criticisms that have applied to nearly every motocrosser out of the Far East.
In 1967, things began to change. One leading manufacturer produced a punchy rotary valve Single, and now Suzuki has come along with what many experienced motocross riders consider to be the best Japanese effort yet — the 250-cc Suzuki TM 250 Single.
The first factory prototype of the TM 250 appeared in Europe four years ago. No one took much notice of it, with good reason, for its performance could hardly be described as earth-shattering.
Suzuki painstakingly carried on with a long, drawnout development program, and even arranged for CZ ace
Joel Robert to test the bike a year or two ago and submit his opinion. He wasn't wild about it, to say the least, so the development continued.
Things have changed — dramatically! On his recent visit to the United States, Joel again tried the TM 250, and was greatly enthused about it! Out in the desert with CYCLE WORLD editors, and on a trip to Saddleback Park, Joel could hardly be kept off the Suzuki. It was like a completely different machine from the one he had ridden in Europe, said Joel, and a really first class motocrosser.
The TM 250 is a pure racer, not a playbike. Anyone who simply wishes to ride around in the desert should leave it well alone. It's just not for the pleasure rider. In fact, Suzuki does not intend to sell the TM 250 in large quantities, but will make it available to anyone who harbors serious racing intentions. This prestige machine will be sold at virtually cost price to serious competitors. Actually, so many things on the bike are hand built that it is difficult to see how Suzuki can make a profit. Price — including the spares kit — is only approximately $975. The kit includes a cylinder barrel, two countershaft sprockets, piston with rings, air filter element and carburetor jets.
Probably the most important single item on any motocross racer is the engine. The majority of riders will sacrifice a little handling ability of a machine in exchange for
power with maximum torque. This is exactly what is offered by the Suzuki TM 250!
Suzuki claims 32 bhp from the engine. After riding the bike, it is apparent that this is not one of the overenthusiastic claims that many factories make for their race machinery.
It will deliver 8200 rpm — more if permitted! In fact, the best power is developed at just under 7000 and 7500 rpm which probably is the wisest limit in lower gears.
There's power all the way through. The Suzuki will run to over 60 mph in the eighth-mile, and that's more than brisk acceleration by anyone's standards.
Actual figures recorded at Carlsbad Raceway were 10.31 sec. at 61.03 mph for the eighth-mile, and 18.63 sec. at 63.38 mph for the standing quarter. This is concrete evidence of the TM 250's performance.
Even with an engine that produces a wide spread of power, it is essential to any competition rider that the gear ratios are as well suited as possible to the power characteristics. The Suzuki gearbox is great. It has only four speeds — though this is no hindrance as far as motocross racing is concerned — and the ratios are ideally chosen.
Primary drive is by gears; the clutch is a wet multidisc unit with five friction plates, mounted on the crankshaft. Final drive is by a single row chain.
Spark for the single-plug engine comes from a Kokusan flywheel magneto and coil assembly. The engine is normally ported — apart from the two exhaust ports — and has full disc flywheels with an H-section connecting rod.
The frame and cycle parts are obviously the result of much careful planning and research into requirements for a winning motocross machine.
The front down tube, for example, is a hefty 1.5-in. tube with the steering head strengthened by metal gussets which extend on each side of the tube from the steering head downward almost to the engine mounts.
Flexing at the steering head is one of the most common faults in ill-handling rough course machinery. Suzuki has found a surefire way of eliminating this defect.
The remainder of the frame fits closely around the engine unit; there are no great wide open spaces between the cylinder head and fuel tank!
From the single front down tube, the frame splits into a Y-shaped cradle beneath the engine, and twin tubes sweep up behind the power unit to join the single top rail.
The really good front fork gives 6.5 in. of travel. The tubes are held by truly large pinch bolts in both the alloy top clamp and steel lower one. The îeason for the unusually large clamp bolts is because the fork stanchions can be moved up or down in the triple clamp, thus changing handling characteristics to suit individual tastes.
Wheel sizes are in keeping with European scramblers — 2.75-21 tire at the front and a 4.00-18 at the rear.
The handlebars do not have any exaggerated rake or high-rise and, combined with the positioning of the footrests, contribute to a comfortable, confidence-inspiring riding position.
The only troublesome point when riding the bike was the wide set of the twin expansion chambers. They sweep upward from the engine unit, just below the seat and alongside fiberglass rear fender-cwm-numberplate molding.
When riding in the saddle, or while standing on the pegs over sharp jumps or rough ground, they present no problem. However, when standing toward the rear of the bike over long jumps — with arms at full stretch — the chambers could lead to some painful burns on the inside of the rider's thighs.
They also could get in the way if the rider were forced to do some heavy footing to get himself out of trouble. Even the best riders experience difficulty sometimes. Anything that hampers recovery is a nuisance, to say the least.
Probably the most impressive point in the handling department is the excellent weight distribution. The TM 250's front wheel will rise only when intended by the rider. Too many machines will rear up and fly the front end at the slightest provocation, but the Suzuki will do so only if the rider gives the bars and throttle a simultaneous tweak. Otherwise, the front end goes light under acceleration, but not high enough either to put the pilot in trouble or lose him time.
Yet another good point is the brakes. They were great stoppers, but could be applied gradually, and had plenty of feel. Progressive operation of the controls is a necessity on any competition machine. It's no good having super stoppers if they are going to jam on immediately and throw the rider off!
All things considered, the Suzuki TM 250 is impressive as a really effective, out-and-out race bike.
U. S. Suzuki has employed a pair of good riders in Preston Petty and Gary Conrad, so the TM 250, no doubt, soon will make a mark on the scrambles scene. Petty, in fact, rode the bike against the European aces on their recent tour in this county and felt that the way it went and handled enabled him to put up a much better performance against the all-conquering visitors than would otherwise have been possible. ■
SUZUKI
TM 250
$975
SPECI FICATIONS
PERFORMANCE
