Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125853
fI.» II IlQ -= IlQ ..:::I g ... g -e- f'- C'l .C'J - :-. 0.. < ., z « , ~ c "' a: u. f- a: « Fast, inexpensive but not quite like DeCoster's SUZUKI TM400 The original frame for the works Su zukis wa s a Cheney design. It has since gone through some modifications as the engineers saw what else was com ing a lon g and kept pasting their cu to ut composites of every European frame up on the scaled graph paper. But Er ic Cheney designs frames to a single purpose and weigh t and powertrain and app lica tio n with a unique and unbending fan aticism . Speculating just a bit, th en, it be comes clear why a steel fr ame c hrom e-m o ly bd en um wei ghing maybe 15 -20 Ibs. designed for a 2 0 0 lb . bike just doesn't make it as a mild steel fram e o n a 250 lb. bike, even if the geometry is slightly chan ged to acc o un t for different weights and stresses. I t might be more accurat e to OK, let's get one thing perfectly clear right from the start. You can ride it. All the misplaced witticisms of other journalists , and horror often Suzuki ridden stories from your friends, secondhand, aside, th e TM400 can be ridden and fairly rapidly in off-road competition. The "K designation , the latest ' version, is improved over all the ones that came before it - noticeably improved . It still does not handle like most riders want a motocross bike to handle in anything near its stock form but it's getting to the point w here you can see where Suzuki m issed in some of the areas and try to remedy the situation rather than throw up your hands in despair and start over. The perplexing thing is that the TM400 really does share several com m on design approaches with the works RN7 3 3 70 's but it goes su b tl y astray from the works execut ion in man y small ways whose sum turns o ut t o change the whole ch aract er of the TM400 quite a bit. Most obvious is the weight. The works RN is between 210 and 2 20 lbs, wet in its various co n figurat ions, Whc~ U , , 40 the TM400 is wetted down with rar e and precious flu ids it is right near 25 0. The engine has 29 more cc displacern en t but it , too , is he avier - lack ing t he m agnesium pieces - and th e power o utp ut is actually a shade less but, note car ef ul ly , not too much less in either a quantitat ive or qualitative sense. Suzuki specificat ions Wheelbase Groun d clearan ce Handlebar w idth Disp lac em ent , , , , Bo re x stroke Co m p ressio n ratio (actual) Carburetion , Fuel cap Transmission ' , Maximum horsepower (claimed) Dry weight (claimed ) , Wet weight (actual) , ...... .. .. . .. .. .. .. ... . -. : , , . 55.0 - 55.7 inc hes , ,6. 7 inc hes " , 35.4 inches , 396cc , 82 x 7 5m m , 7 .3 :1 , 34mm Mikuni VM34SC 2 .1 U.S . gallon Dow n l -N·2 ·34·5 up 36 @ 6 000 RPM , , , 23 5 lb. , 255 lb. [approx.) , " say, especially if the geometry is slightly changed. Both the works RN and the TM400 have a short swingarm and not too much trail, the better to execute those incredibly sharp comers with, we presume. But the swingarm on the works bike is just a tad longer, made of lightweight alu min um and very rigid. It hangs the rear end out only so far and doesn 't whip back indu cing all sorts of unplanned co unt era ctio ns around the pivot point. The TM400 swingarm is barely 18 inches long and flexes. It is not made out of lightweight alum inum. The pattern of slight deviation in execution to attain a bike that can be sold at a co m p et itive price starts to ad d up. I can sympathize with the Suzuki engineers who are amazed that such subtleties so change the abilities and character of the bike. But they do, You can't escape that fact. Look at the engines. Both works an d p roduction versions are flat black, high-revving, mean-looki ng muth as tha t produce plenty of horsepower. Nobody with any , sense of proportion ha s: accused t he Suzukis of heing slugs. The ' idea worked ' brillian t1y on the, works bik e. Let the revs climb to maximum horsepower and keep it there. Roger, and Joel and Sy lvain and Gaston and Koji and a ll y o u other fa st dudes. The power o n the works ma chine hooks up through a big 4 .50 bristly, sticky tire and the rigid swingann holds it back . • there pushing 'as it overcomes .the resting , .