Cycle News - Archive Issues - 1970's

co rrec t th e ho tto m in g by putt ing m or e pr eload into the springs and a lot of rid ers do t ha t b ut it isn't the bes t way . Test yo ur rear suspension by riding hard, at racing sp eed. o n a tr ack th a t is abou t as rou gh as you n o rmall y ride. Your rear sus pension sh o uld bottom occasio na lly - may be: o nce o r t wice per lap - b ut not all the ti me. If it nev er bottoms. yo ur rear springs are too stiff. If it bo lloms a ll the t im e, your rear springs are n ot sti ff en ou gh. This is a reliab le indica tio n pro vid ed th e damper s ' ar e in good co nd iti on . Th is gets com plica te d b ecau se th e dam pe rs d o en te r into the p icture. Rem ember th ey are a lso opposing suspe ns io n m ovement by th e internal fri cti on o f t he damper. 'The wheel is co nnecte d .'0 the fra me in t wo wa ys: it is co nnecte d by th e sp ring and it is co n nec te d by th e damper . When th e wheel is ex erti ng a force upward t o compress th e spri ng it is als o telescoping th e damper. Whatever amo unt of force it tak es to compress the damper is subtracted from th e total force fro m the wheel. T he refore if the dampers arc wo rking rig ht. th ere will be less force for co m p ressing the sp ring . The reverse of th at is if your dampers aren ' t doing anyt hin g, then all of th e force fr om a bump in th e track go es to wo rk on yo ur suspen sio n springs and th ey will bottom a 101. That so unds li ke a Chinese puzzl e th at nob ody can eve r so lve. bu t it ca n be so lved by so me rid ing t ests pro vided the da mpers are in good shape. If yo u start wi th a n e w motorcycle or a new pair of " sh o c ks " - meani ng dampers of so me good bran d, th en you test by riding until you get the righ t sp rin gs. That com bination should las t a long time an d fina lly you may notice th at it is bo tto mi ng a nd the rear end is bo uncing aro und. Wha t do you sus pect wh en th at happen s ? T he dampers are worn o u t and need rebuild ing or re p lace me n t. Rear springs do n 't often los e st re ng t h: front o nes do. If you suspect thaI yo ur spri ngs have los I stre ngth, ho w ca n you check th at ? Get o n the bike an d notice if it sags down m or e than usual und er you r weig h t. If so , it's the sp rings because th e dam pers don 't do m uc h wh en you are just sitting on th e b ike. They will let th e suspensio n sag as far as it wants to. Now ler 's revi ew the se t up procedure for yo ur rear suspension: 1. Be cer tain your dampers are In good co nd itio n an d wo rking. 2. Rid e th e mo t orcycl e a t racing speeds o n a tra c k and ch ec k sp ring stiffness. Go to stronger or ligh t er spri ngs un til the sus pe ns io n botto ms occasionally when y o u are riding hard . 3 . Each time you try a differen t se t of springs, rea dj ust th e preload. Sometimes you have to buy two and ma y be three sets of springs before you get the right co m b ina t io n . If y o u want to find what's really right and what really wor ks, yo u are going to have to d o it th at way . Experiment aro u nd and try di ff eren t ones. L et ' s thi nk about building a sus pension t ailo re d to do the best job for t he very wo rs t condition on a ne w track. The place on th e track wh er e suspens io n is obviously th e m ost important and wh er e rid ers tend to fa ll a lot o n acco un t o f the track itself. Wher e i s tha t pla c e? T he wh oop-de-doos. You have seen b ike s ge t in to t ro u ble there all th e time. T he rear end sta rts crow-h o ppi n g from sid e 10 side and wi th each hop it gets hi gher and high er into t he air and finally the rider co m es o ff or crashes . It's pretty obvious that so me t hing is t hro wing th e rear en d o f the bi ke up in th e air. Lo ok a t t he tra ck an d yo u ca n eas ily see wh at it is - th e bumps are do ing it. T he wh oop-de-d oc s are made by th e motorcycles in the first p lace an d Con t inued o n page 33 9AN (}A8~/El VALLEY M. a PRE.=ENTS LC'l ... U ..0 E u > Z o •• Use This Entry form or District 31 Enhy Blanlc LIMITED ENTRY BY MAIL ONLY ENTRY CLOSES NOV 15 r---------- ~----------------- - - -----------------I SAN GABRIEL VAL LEY M.C. 1529 Meadow Glen Way Hacienda Heights, CA 91745 Include Entry Form & $11,25 District 37 Rid ing No . R id ing Cl ass (Ci rcle One) Novice Am ateu r I I I I I Expert For Further Info : 213·964·3420 Rid ing D iv is ion (ctrcre One) San Gabriel Valley Mot orcycl e Club Barstow to Vegas Heayyweight Lightweight Trail Ult ra L ightweight NAM E O F EN TRAN T (p oease pn n t ) AGE _ T ELEPHONE ( _ CITV _ __ _ _ _ _ _ A DDRESS STATE _ Z IP _ I a m a bana fied member af th e cl ub AMA No . Expires Make of M. Cyc le Di st ric t Riding No . Engin e No . I w ill e nter in the: Exp er t r Cu. Cm . _ .,..- _ J A ma t e ur [ I Novice I J cla ss . Rid ing o r Sidecar pa rt ner (or team Members) : Class A End uro Ri d er: V es ( I No ( I _ We ar e entering as a tea m : Ves ( J No I I The undersi gned entrant by a ff ixing h is initials b elow, ack now led ges th a t he ass u mes the risk o f a ny loss fr o m in ju ry or property damage to h im se lf or to ot hers , due to h is pa rt icipa t io n in this e ven t a nd he h er ew ith speci fically holds ha rmless from a ny said los s Ihe A me r ica n Motorcy cle Associ at ion , Sports Commi ttee , District 37 AMA. Inc ., Ihe spo ns ori ng cl u b or organ izat ion, and Ihe ow ners of the real property o n wh ich sa id eve nt sha ll ta ke place . (ent ra nt's a nd /o r parent' s initia ls) If e ntran t is under 21 a nd does no t have c ur ren t D istrict 37 Card indica t ing not ar ized co nse nt is on file , Parent o r Guard ian must Sign here ack n owl ed ging his o r her consent to the terms of en try . Th e u nd e rsigned does hereby certify th at he is du ly Qualified (Circl e Onel Am a t eur/E xpert/N ovi ce cla ss motorcycle rider ha ving been so Qualified b y a co mpetent organization . It is further und erstood an d agreed that in the event I a m inj ured fro m w hatsoever cause du ri ng the event co ve red by thi s a pplica tio n, I he rew ith co nse n t to a nd a ut ho ri ze first a id a nd a rrO ula nce se rvice as provided by th e sponso ring club or property owner , a nd fu rth er hold all pa rt ies harmless from any consequences o f said a id . Un der the rules an d sanctions of the Amer ican Mo to rcycl e Assoc ia tion, I herebv agree to co nf or m a nd comply w ith t he rul es go vern ing this contest . Signa t u re of entran t : Dat e: I I I I -''- _ 19 _ _ I I I I I I I I I I I I I I I I I ~----------------------------- ------------------~ Tell them you saw it in Cycle News. Hodaka Montesa Carab cl a "~J _ .A Bill Robertson Honda Motorcycles

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