Cycle News - Archive Issues - 1990's

WORKBENCH By Nate R auba ~ L Vorkbench is a weekly column dealing vith mo torcycle main tenance. perfornance and equipment. Have something l13t Workbench can address? Drop a line to Workbe nch , Cycle News, P.O, Box ~98. Long Beach, CA 90801-0498. ~ ~ ~ --~ Don't let sag get you down ast week in Workben ch we answered a reader's leuer co nce rning for k sp ring sag, so this week we'll deal with the rea r suspension. Suspension sag is required so that the suspension can work both ways. Positive suspension acti on (co rn p ressi o n) soaks up th e bumps, while negative action (rebo u nd) pushes the wheel down as it trav els over a hol e. Thus, rear suspension sag is req uired so that th e suspension can extend the w he e l into the hol e to m aintain traction. Si nce street riders enco u nt er few, typically small holes, th ey need very little sag. Abo u t. 75 10 1.5 inch es of rear suspension sag with the rider sit ti ng o n the bi ke is all thar's req u ired for road racing or sport rid ing.comm uti ng o r to uring ride rs ma y want sligh tly more. But mot ocross and off-road riders encounter numerous b u mps a nd hol es, the refore they need greater sag. According 10 Paul T hede o f Race Tech, a hop. up shop th at specializes in fine tunin g sus pe nsion compone nts, o ff-road suspe ns io n sag shou ld use 25-33% o f the total available tra vel a t both ends. Th ede says that there are no magi c nu mbers, bu t tha t sag sho u ld be set for what th e rider wa nts the mach in e to do . Less rear suspension sag makes th e bik e's rear end sit hi gh er , increasing the steering a ngle for qui cker turns. The front end will th en be less stab le and have sligh tly more weight placed on it, More sag low ers th e rear end, increasin g rak e for greater stabili ty while slo wing the turning ability of the machine. (For more on rake and tra il , see th e Ma y 30 issu e.) eui ng sag usually requires the assista nce o f a friend to take measu rements whi le yo u ' re on the bike. However, G MP P rod ucts (8601 International Ave. # 106, Ca noga Park, CA· 91304, 818/ 718-8038) makes the Sag Rit e measuring 1001 whi ch inserts into the rear ax le a nd a llows o ne-pe rso n measu remen t o f sag . To set sag you must firs t set the bi ke on a sta nd with th e suspension fully extended , a nd take a measu remen t /rom the ax le to a fixed , nearly-ver tica l point o n the rear fende r. Then take lhe bi ke off th e sta nd a nd clim b aboard . ':'h ede reco mmend s th e rider stand on ie Ioo tpegs, whi ch ar e close to the like's center o f gravity, instead of suing on the seal. Compress the suspension a nd let it rse slowly, th en measure the stopping loinl. The diffe ren ce between th e two neasurements is th e sag . T o cha nge ne sag, simply turn th e adjusting ollar on the shock spring in or o ut , For a n even mo re accurate measurenent, T hede takes a thi rd meas urelent by lift in g the rea r end, wi th the id er still in p lace, ta ki ng another neasurernen t where the suspens io n eu les. T he n a verage th e two measu renents 10 set th e sag . Usi ng this me tho d o u ca n also determine the condition ( yo ur sus pe ns io n linkage. A 3m m iffer ence in th e two meas ure me n ts is Kcell ent, while 10mm o r more means i's time to service th e lin kage . HI-PERFORMANCE PISTONS - ;'"-"": =::= :;;; ....... - . : .. "' - - _ ..--.,L.A SLEEVE CO. GENU INE RAC ING PARTS L-:..---------~ MANUFACTURED IN JAPAN Parts a nd Accessories , Y ahasS &D am treet irt , Super J et ,H usqvama•D ucoti , Husoberg ove unner , KTM ,W R ,W J ove ammer [i MX/ATV High performance race style pistons manufactured from special high-silicon aluminum alloys. Piston kits supplied with ri ngs. clrcllps, wrist pin . For leading makes and models. See your dealer. = M Order· U ail PS Rnancing andInsurance ' Monday - Saturday 9:CO - 6:00 7563 Indiana. Riverside (Hwy 91 & Madison) (714) 687·1300 LO S ANGELES SLEEVE CO., INC. _ft. 8311 Ch etle Av e.• Santa Fe Springs , Cal l or ASubscription is aboredom prescription CA 90660 (213)945-7578 tor your tr. . catalog and decaf., JULY 21-22 1 990 A D VAS CE TICKET PRICES GOOD U!l7/L J ULY 15, 1990 FEATURING SU PE RBI KE, 250 GRAN D PRIX, PR O TWIN , AND SUPERSP ORT RACL~G DURING WH AT PROMISES TO BE A MEMORABLE WEEKEND OF W OR LDCLASS COM PETI TI ON. ORDER TICKETS TO DAY A T ADVANCE SALE PRICES l MIAMI'S MOTORCYCLE FE~ER... ! § .., . F CATCH IT! FOR TICKET INFORMAnON CALL: (305) 665·RACE Payment must be by check . mone y order , or charge account. All ord ers paid by check wi ll be held for' a working days . Pv1a.ke checks pa yable to ; MIAMI MOTORSPORTS, INC. Please charge my ticket order to my VI SA or MaslerC ard accou nt, Acco unt Number' _ E xpirati on Date ---,.=;- i=';,- Signatu re VISA D Mas tert::ard D Tickets ordered atter July 2. 1990 must be pick ed up at the Miam i ADVANCE PRICE TYPE 15 .00 General Admission 25 .00 Open Grandstand Reserved Grandstand 45.00 10.00 Paddock Pass Subtotal: Postage & Handling TOTAL DUE: Mo torspons offIce prior to Ju ly 13, 1ggO or at the Will Call Boom Name at me track on Sa turday. July 21 or Sund ay . Jul y 22 . Address Mail this teem to: Miami Motorsp ons , Inc . P.O. Box 5S8090. C ll y/S l a te/ Z ,p Moami, Florida 332 55·8090 Phone Number REG. NO TOTAL PRICE 20 .00 35 .00 55 .00 10.00 2.00 _ _ _

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