Cycle News - Archive Issues - 1960's

U5UMIOIl Dill.... ElciuslYll, for air ", cotled -.gilts. Distributed Nationally by KASUMI OIL CO. FOR DEALER INFORIIAnON 25111 Ave. s.. IIaleo, C.Uf, Pho.a • A.... Coda (415) SlH240 or nl-4S35 Stay Stock --------------, : Ho.. C.'"r City I !. ~§A .: L _S!~~'!'!.1'1~~l J ~ ~ : YlTtHLESS . : .e : EDDIEOR CROWELL : ... I~ : ... ,H5l1 ... ... ~: TFUI-IV~ ... . ................... ... ... SALES· PARTS • SERVICE ... 10427 Prairie, lI'II._a First, I think that I should put in a word for running the machines set up completely stock. While AFM rules allow for flexibility in engine preparation, I believe that in very few cases will any marked power increase be possible without a complete, skilled engine modification, and even where this is attempted one will sacrifice the very brood power band, which at present is one of the motorcycle's most excellent features. Reliability might also be imperiled if modification is attempted. Standard ignition timing is recommended; for long races points should be tightened with maximum force, possibly with an "impact" driver. Caution should be exercised when doing this, though, for the impact could conceivably change the timing slightly• Igniting Tbe Gas TELL THEM YOU SAW IT IN CYCLE NEWS / by Byron Black lhe 250cc and 350cc twin-cylinder Kawasaki's have excellent potential in production rood racing, besides being superb rood machines. In less than two months, I have taken my 350cc. A-7 "Avenger" to ten first places out of fourteen races entered (I had four retirements, three of them due to crashe s), and managed to do very well against machinery of considerably more displacement, both in Production and GP classes. The following are a few suggestions which I would make to anyone else who is contemplating road racing their A-I, A-ISS or A-7 machines, based on my own limited experience. ... ... ... ... I have used a spark plug one heat range colder than the NGK B-9Hc which the motorcycle comes equipped with. While I use a Denso W27FPt (this is a Japanese brand which I have not yet seen in this country), this corresponds to an NGK 1110. I would advise against using a colder plug - the bell-shaped combustion chamber insures that the electrodes are located far enough away from the piston face to prevent any piston damage, and a colder plug might foul out under certain conditions. Pistons and piston rings should be set up with standard clearances. Rings should be replaced every three hundred miles or so, as this is a cheap and easy way to keep maximum power and prevent blOW-by, and I have replaced pistons at seven hundred racing miles. Modifying tbe Gearbox ............... .SAVE ... ~ ~ ; USED • HOlDA PAirs: Wilmington Discount Cycle Center 1505 Avalon, Wilmington, Calif. nUllI C 'l'E 4-0558 • • • nU\lA I"AMI\. T~ 7233 CANOGA AVE. 346·3/00 ..***************~ ! THE TWO-WHEELEI.: * SUZUKI ~: *' RtIlIJ .. I....ate Dell,.,! *' **m .. Con. Ave. s.. a.HnIlao, CAlif' (714) 115-3445 \ •••************** The mainshaft in the gearbox on my machine had a slight bit of lateral play, so I shimmed up the right side to insure better meshi ng of shifting dogs. The shifting mechanism itself, when set up properly, is adequate, but I have noticed that the small stud used as a shifting stop tends to work loose: this caused severe overshifting problems on my machine. When I overhauled it I set this stud more nearly flush with the shifting plate upon which the shifting rachet is affixed, used a special locking compound on it, and set it at a slightly different angle, so that the slight amount of wear I noticed would have no effect on the point at which the shifting plate stops. When Ifell at the 250 Mile race at Cotati, I fractured the upshift hook on the shifting rachet, and it later snapped off, causing me to retire. Afte f a severe fall to the left, it might pay to check this rachet, to see if it has been cracked by the sudden impact put on it by the shifting lever hitting the pavement. Carbnretor Adjustments I have found that the best setting for the carburetor needles is in the middle position, and I .have not changed my main jets for any race yet, since plug chops have shown a good color, and performance has likewise been satisfactory. The float levels should be checked,though,and the slides adjusted to open all the way out of the carburetor choke. It may be necessary to change the adjustment on the oil pump actuating cable to effect this. tn my case, I have set the oil pump to open at approximately the same time as the carb slides. The carburetors should be securely fastened onto the rotary valve inlet, since they tend to vibrate loose. The exhaust pipe clamps also have an annoying tendency to vibrate PRODUCTION ROAD RACING KAWASAKI TWINS loose, no matter how tight they are fastened, and thus should be springloaded to minimize this problem. This is accomplished by drilling small holes in the clamps, and in the head fins, into which springs of ~ or Inch diameter are hung. * Racing Tires Racing tires are definitely recommended, to take greatest advantage of the handling afforded by the superb frames of these machines. I use Japanese Yokohamas, inflated to 29 pounds front and 31 pounds rear (hot pressure). Wheel alignment should also be checked, since the marks on the swing-arm don't seem to correspond very well to alignment. Ground clearance Is one of the only real problems with these machines. The chromed clamps holding the mufflers onto the exhaust pipes tend to grind and wear through rapidly, the shift lever can hang up on the pavement, and the footpegs also ground easily. Tbe first problem can be relieved by weldmg or gluing curved pieces of sturdy steel stripping to the outside portion of tilese clamps. This will wear away before the clamp does. If the fixed part of the footrests is heated and bent up, and the shifting lever accordingly mounted higher, a little more clearance can be obtained. I try to help cornering clearance by shifting my body weight into the curve, and straightening up the machine a little to clear the pavement. This is possible with the clip-on type -Thruxton" bars I am using (available from most dealers). The brakes on these maChines, e specially the A-7, are magnificent, and indeed better than on some racIng machinery I have ridden. They will progressively increase their action until the wheel locks, but all in a safe and steady manner. Brake lIaintenaDce There is a price to be paid for this, though. On some machines, the linings generate excessive amounts of dust, and should be cleaned up frequently. With the great amount of heat created in the brake durin g a race, the linings tend to glaze a little. I attack this by a light rough·"::':f~'~f:':':I:.:.:.:.:.:.:.:.~.:."'j;'./,/~·:... .~, l/, ~ ing up of the linings with a 11400 sandpaper, slightly dampened to lessen dust flying around. Even with such care, the brakes will still fade. and I have found it necessary to cut ventilating holes and Install brake scoops on my machine. Otherwise there is the danger of running out of brakes during a long race. I would recommend replacement of the drive chain every seven hundred fifty to a thousand miles, even with careful and frequent lubrication. A racing (pre-stretched type) chain is best when replacing. lIiDor 110 ds One minor modification which might result in more power is to machine off the flange on some of the Mikuni carburetors, which was originally designed as an air cleaner mount., as some Yamabas have. The engine cases fit against the carbs quite closely, and there may be some air restriction here. Also, running with the rubber carburetor covers pulled out is said to be good, though insertion of a fine screen mesh to prevent any bits of gra ve I to enter might be a good measure. My mileage during hard racing has averaged about twenty miles to the gallon. A quart of oil lasts about eighty miles at racing speeds. As recommended by American Kawasaki, I use Torco 2T in the oil tank, and 3011 rpm DELO motor oil In the gearbox. It is best to change the gearbox oil after each race. And don't forget to drill and wire your drain plu g. Gearing on the machine Is about right for Carlsbad, a shade high for Whiteman, and a bit low for Cotati. Shifting at 8500 rpm (where on my machine the engine refuses to wind any higher) and attaining the same speed in top, I have noted an indicated speed of 125 miles an hour down the back straight at Cotati. This corrects to abou t 112 or 113 miles an hour true speed, which is not bad for a rood 350• When a dead engine start Is attempted (FIM-type star t) it is important that the engine should be as hot as possible, or otherwise it will nottendto fire and accelerate cleanly when bumped. Good luck with your Kawasaki. see ,You at the races. "., '" :. ::.:. ::::,0,: .. , . :::.-.: ' ,,', ........., '.' .

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