Cycle News - Archive Issues - 1970's

(A bove) Ke ih in 31m m CR racing carbs handle air/fuel in take. (Below) Hand-bent 4-into-1 pipe handles the exha ust gases. !!.st as it is, the CB400F can't win by itself. Steve Schrader helps. be realized through hard work and much experience. Using RSC (Racing Service Center, a Honda subs idiary) pistons and L.A . Sleeve Co. sleeves, the barrels have been bored out to 56mm yielding 492cc. Kazuo highly polishes the crowns of the pistons. This is done for seveal reasons : first , it eliminates any sharp edges which could become hot spots leading to pre-ignition , second , it retards ca rbon build-up which can also lead to pre-ignition. The cylinder head has been given the full pon and polish treatment. Compression ratio has been bumped to 10_7: 1. The intake valves are 27.5mm for an increase of one millimeter and are availabl e exclusively through Ontario Moto Tech. Both valves are shaped and polished for optimum gas flow . A hand bent 4-into-l pipe releases the exhaust gases. In 1977 , Steve used the "Ontario" grind camshaft. It is a fairly mild cam which gives good power over a wide rpm spread, coming in at 5 ,000 rpm and pulling to 11,000. For 1978 , the feeling was that he could sacrifice some powerband for more power at the top of the scale. Kazuo ground a special cam that did just that. But, the resulting narrow powerband (9,000 to 12,000 rpm) made riding more difficult. Next year , Steve plans to return to the "Ontario" grind making the bike easier to ride. Controlling the valves at engine speeds of up to 13,000 rpm is a ' set of , springs made to Yoshima's specifications. Contributing to the narrow powerband, but, also contributing to power, is a set of 31 rnrn Keihin CR racing carbs. Ignition is provided by a total loss system. No charging system is used thereby saving weight and eliminating horsepower loss through magnetic drag. A "Dyna III" pointless breaker is used in place of the stock contact breaker set -up. Mike Burke coils fire NGK D12E spark plugs through Autolite plug wire . The stock crankshaft has been lightened to im p rove quick-revving capabilities and polished so that cracks don't lead to fractures . Changing the linear motion to circular is a set of the popular and very strong Carillo rods . Power is de livered to the stock transmission by the standard clutch arrangement. The clutch plates , however, are replaced with Barnet t items which are squeezed by heavy duty springs. The clutch slipped a little when I rode it , but that was a t the end of the season and the bike was due for a general "spri ng" freshening up . Clutch lever pull was moderate. Arnso il Racing Oil has been used exclusively and is moved through the motor by the oil pump wh ich has been modified by Kazuo for increased volume and pressure. Hot oil pressure is normally 75 to 85 psi and is now cooled by a Lockhart coo ler. The previousl y used oil cooler was ob ta ined from Earl 's Race Car Supply, but, after several failed from vibration, the . Lockhart was tried. The braided steel oil ·lines were purchased ' from Earl's Race Car Supply. The chassis has been modified quite a bit although the original frame and fork assembly are used . The frame has been gusseted to resist flex ing and th e swinga rm has been replaced .with on e manufactured by Trackmaster Ra cing Frames. Bronze bushings are used at the swingarm pivot and the shocks are mounted conventionally. The front forks use stock springs and damper rods. The standard amount of 20 weight fork oil is used in conjunction with I' in c h sp ring preload . The lower steering stem is strengthened by taking an old stem and cutting off the cla m ps. These clamps are then welded in place under the clamps on the stock stem . This effectively doubles th e purchase area on the stanchion tubes thereby increasing rigidity. Suspension in the back is handled by S&W Freon shoc ks with 70/100 po und 'springs. Steve prefers to use Michelin tires. Up front he mounts a 3.50x18 S-41 on a WM3 D.LD. rim which is laced to the stock hub using eight gauge stain less spokes. Either a treaded TY4 or a SV5 slick is mounted on th e WM5 D:LD. rear rim . The rear wheel also uses eight gauge spokes for increased str engt h and-rigidity. When Steve squeezes the front brake lever , the Honda GLlOOO master cylind er forces DOT 4 brake flu id through the braided steel lines to the dual Honda CB750F cal ipers. The calipers work on Kawasaki Z-1 front d isc rotors which have been Blanchard ground from a stock thickness oL275:: to . 160" . Blanchard grinding assures uniform thickness because both sides are ground simultaneously. The rear brakes are stock. A quick-turn throt tle, manufactured by Nippondenso, is mounted on the right T ommaselli aluminum c1ipon . Steve di d an excellent job of making up his own rearsets and li n ka ge . Ste ve monitors what the motor is do ing by th e Stewart-W arner oil pressure a nd oil temperature gauges and by the speci a l Nippondenso racing tachometer. I had ridden Yoshima's orig inal 450c c screamer two and a half yea rs ago and was amazed a t that time , not only by the abundance of power, but, by the immensity of the powerband. I was expecting the same only more of it. Unfortunately, sometimes developmerit takes a step sideways. Such was the case with Schrader's bike. T here is more power, for sure, as evidenced by my lap times . But, unfortunately, the narrowness of the powerband made rid ing at speed more work than it needed to be . The bike handles like a dream. It reminds me a great deal of my TZ250 in the ease of which it ca n be flicked from left to right . The suspension was pleasingly taut - not soft enough to wallow and not so stiff as to make riding unpleasurable . It takes a good com bina tion of rider and equipm ent to win a race. And an even better combo to win a championship . It speaks well of Steve Schrader, the Honda CB400F, a nd Ontario Mot oTech that they hav e won th ree cha m pi onships in two yea rs. • 2'3 '

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