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/125442
I WOULD YOU BELIEVE ANOTHER 500-Expert Class Win? THAT'S 4 IN A ROW Chuck M iner! makes another fir st place performance look easy aboard his new 441 BSA Vi ctor, last Sunday at the Oi lers M. C. TT-Scrambles, Imperial Beach, Cal if. ... It' s just getting broken in.... SEE THE W NDERFU L WHEELS OF BSA O AT YOUR BSA DEALER'S... , for tlte name and address of tlte deaier nearest you, contact BSA MOTORCYCLES - WESTERN 3014 Braadway, Oakland, Cal if, Ceriani Suspension MOTO-CROSS & ROAD RAONG FORKS IN STOCK , FOR ALL POPULAR MODELS •• 5127.50 For lip to 100(( Lightweights - $97.50 SEE THEM AT OUR BOOTH #2! AT THE CYCL E WORLD SHOW a 'm·mZ276 lal nIIn ' CIiIBI'Iia 918lI3 **1 C 289 ' 5039 removed and t he oil rerout ed with ~ i nch cop per tube. A B arnet t clutch is us ed t o handle th e added pow er. The transmission which is stock except f or switchin g th e se cond and third gears to pr ovide closer ratios . It has not been found necessary t o drill extra oil pas sages to the cy l i nde rs from th e gallery that crosses the front of the cy linder block as i s often done on th e 350cc conve rsions . Movin g up to the head. a great deal of wo rk has been done to the por ts and combustion chamber . All th e car vi ng in th e ports and combustion chamb ers co nforms to the dictate s of flow te sting equi pment and dynamom eter. Work on the head provides a 10~ to 1 compressi on ratio. The ports are plugged by standard Honda valves actuated by an ex peri mental Harman & Collins camsh aft whi ch is but th e lat es t in a lon g line of cam typ es . The fuel mixture i s supplied by the 26 mm c arbure tor norma lly found on the larger CB 77. Tunin g of th e intake and exhaust tracts was die rected toward widenin g th e pow er spread and incr easin g the torque rather than peak pow er . The end produ ct of all this work is "3D horsepower" at the rear wheel with racin g pow er availabl e between 8000 and 11000 rpm but usabl e pow er is t o be found as low as 6000 rpm and over-revving seems to hav e no effe ct oth er than a drop i n th e engin e's output. Although the engine is tom down after e ac h rac e. main tenance i s usually res tricted to a normal tuneup, a valve grind every tw o weeks, and a set of rings every eight to t en rac es . Extensive use of aluminum and fibe rglass has brought the Honda's wei ght down to 225 pounds. P er f orating the head, cylinders. and cases wi th a few hundred holes coul d drop th e weight a couple of ounc es but it is not considered worth th e efforty et. Handlin g improvements hav e been wrought by lengthening th e swinging arm three inches and using nin e ounces of 30 weight oil in each fork leg rathe r than the recommended 20 weight. Solid struts have replac ed the rea r sus pension unit as is standard procedu re in flattrack machines. Adoption of the hy draulic . st eering dampner from the CL 72 Scrambler has greatly improved th e stabili ty of the bike, ri d ers repo rt . Removal of th e alternators stator to eliminate its power-robbing drag has resulted in the adoption of a total-drain ignition system. Excell ent results have been ob tain ed with this system in whi ch a battery prov i des the contact break ers with c ur- ~ WINS 1 ;~~~~o \1\ \a~~ H& H National Championship t 'oO"" C OVERALL Ust GARY CONRAD see yo... l ocal L. A. Dealer s Al lied Cycl e - NO. Hollywood Al li ed Cycl e - Newhall Jack Bald win - Sant a Monic a House of Yamaha - W est L os Angeles Hockl es • Torran ce SIeve Hurd - Monleb ello K &N • Ri versi de Bil l Krause • Ingl ewood Lamoreaux - Sunl and Robert M. Law • Anaheim Mason Motors - Pasadena • Sepulveda Mi ssion Hills Shell Motors • Lynw ood Temple City Honda· T empl e City • Burbank Tracy's M/C All parts In stock. So See us or Your Greeves Deal e, I NICK NICHOLSON MOT ORS 11629 Van Owen Sl reet , North Hollywood . Slarter bulge on left si de case has been pl aned off to ai d f1allrack cornering. rent without the benefit of a charging system . High performance is the goal and that is just what they get. With th e geari n g used at Ascot, top speed is about 85 mph and th e av erage speed is k ept up to 80 or so by the exce l l ent handlin g of th e machine and good acc eleration. CHAS ING STEEPLES A steep lechase (TT) mount starts with a CL 72 Scrambl er because of the handling charaeteristics of its frame. Th i s fram e and the neces sary rear sus pensi on boosts the weight to around 240 pounds. Th e Flattrack er' s engine output must be l ow ered by five or si x hor se powe r to provide th e fl exibility de-