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/125575
..,. .... Fairground First at Orland By c a r olyn B. Ric hards ORLAND, Cal., Aug. ll-There is s omething new under the sun - at leas t there is under Northern California' s s un. A '" TT Scr am bles r ace a t Glenn County Fair, .... s pons ored by Willows Scr a mblers M.C., a:; was the fi r s t motorcycle ever held a t ~ the fai r grounds. Photos by Jay E . Ric ha rds Held before a stand- ful l of en thusrastic fans, the event called out 70 r iders from al lover the norther n pa rt of the state. Through cooperation of the Glenn County fair board, trophy girl for the afternoon was Ros e Gonsalez, who was crowned Miss Glenn County 1969 on Aug. 9. ~ THE 45 0 HONDA , PART III: THE ENGINE :fr V) Crashes After Winning Kawasaki-mounted Joe All en grins to himself alte r taki ng the checker for 100cc Main Event victory. He also won the Tr ophy Dash. Afte r B.N. ( Windy) Foreman of Reno, Nev., had won the 500cc Trophy Dash, he turned around to see how his buddy who had crashed earlier was doing, and put his Honda 450 through the fence . Though For eman wasn 't hurt, his machine was so torn up he was unabl e to ride In the Main. Dusty and hot as it can only be in thi s section of the country, the afternoon was a success for both the fair an d the Willows Scramblers. F or the wheelle contest, an extra added attraction, Mark Rieland, San Carlos, did a wheeli e down the front s traightawa y of the half -mile track to win a big trophy and a kiss . When the 250cc Amateur/Expert Main started, both Bob Va ughan, Oroville, and club referee, A.A. Von Seggren of Wil lows, had their hands up. Vaughan's Honda wouldn't s tart. After are-start, Va ughan rode from his expert positi.on to win the six-Iapper , (Re s ult s on page 20) By Dick Kilgroe with Peter Dworkin The only negative aspect of the original 450 engine design we found, was the totally inep t, mos t poorly designed, an d i ncompe tently ratioed gea rbox we have ever had the misfortune to attem pt to use for racing purposes . Like very other feature incorpor a ted in to the " heart of the rock" It proved surprisingly ru g g ed , but r igidi ty of s tructure is quite secondary toanability to functi on, and function it would not . In comparison, the new 5-spee d gea r boxe s are so nearly perfect In their choice of r atios, an d in the imp r oved li nkage design that one feel s almost a sense of guil t a t as saulti ng the fo r mer model, but it Is true that were It not for the clumsy 4- speed, the 450 could consistentl y fini s h in the first over-all winner' s circle. The rest of the engine, however, is a mode l of r eliability. We wer e ab le to vigo rously contest the AFM 500 class for two s easons, covering some 30- odd r oad races, before it even needed a ring and valve job. Despi te the fact tha t it was turned as high as 12,000 rpm cons istently, the original cams, pistons, crankshaft, torsion ba rs, and gears are s till alive and doing well . Along with the following modifications, the se old fai thf uls 'cr ank out a soli d 49 hp at the rear whee l. First Bi g Gain The first per fo rma n ce gain we achieved resulted from welding up the stock 450 pis tons to approximately 10-1 comp ression ratio. This imp r oved the "out-of- the-corn e r" acceleration to the point where our machine was abl e to co mpare favorably with a 40- inch Triumph, despite such negative fa ctors as the corpulent figu re of our racer , an d the unmatched horrors of tha t s tumbly gea rbox. We can' t r emem ber any r aci ng pistons tha t worked better or lasted longer than the reworked s tock articles . Our ne xt big lift came with the aid of the compe tent a nd knowledgeable people at Precision Machining whos e s upersuccessful extreme-duration mild- lif t RR cam helped the 1967 250- mile production winner Dave Burchards an d Bill Ju dkins to victor y completely unai ded by any other engine modificatio ns besides packing the torsion bars from 3 to 61bs . (Thi s procedure, inci dentaily, is heartily endor s ed by us as bei ng far preferable to hassling with the hangups Involved In instailing vai ve sp rings .) Our e xhaust sy s te m can s tand proudly next to that s weet PM ca m as another pe r form ance boos ter . We utilize 2" header pipes , an d as big an exhaus t port as we could obtai n. Thi s exha us t port the ory, we point out, Is in violent oppos ition with the Ideas of other Southern Cal ifornia tuners who feel the opposite s eat width and ti ny por t diameter ( 11/2" ) works better (with a high- lif t carn.) Due to the fac t that the P M cams s eem to be powering the winning ma chines In r oa d racing, we recommend thei r concept over that of som e other ca m manufa cturers whos e implementa tion pos es design pr oble ms due to the a utoma tic increase in torsion bar tension r esulting from attenua ted cam lift. The igni tion system posed a problem which was solved only as a result of a rather expens ive engineering job accomplished by the people at Precis ion Machining. The points i n the or iginal system tended to double-spark at a round 10,5 00 r pm as a result of an endemic wobble in the cam. This s traighte ned itself out past 10, 500, but the res ultan t cutilng-out was a rather severe annoyance. The P M mechani cs wer e able to graft a Yam aha 100-Twin magneto onto the cr ank , thus bypassing any contact with the ca m and its wobble at all. This r esults In constant, smooth performance from 5,000 on up through 12,000 rpm; clean, strong, and dependable . A D A P T - O - F L E X TORQ U E WRENCH FROM STURTEVANT The Motor Spor ts Division of P.A. Stur tevant Co. announces two new patented torque wrenches designed an d cali br a ted to meet the needs of profes s ional mechani cs and enthusiasts assembli ng or wor king on high pe r formance equipment. The new tor que wrenches fea tur e a unique in terchangeab le swiveling drive square which can be removed and replaced in le s s than 10 seconds. The dr ive square on one model has a cap acity from 0 to 150 foot pounds with graduation s of 5 foot pounds In 1/2" ; the other model has a 3/8" drive s quare and has a capaci ty fr om 0 to 600 inch pounds , with graduations in s teps of 25 Inc: New Sturtevant torque wrenches. ~-CU S T O M - ~ c:r . G . cce s' s o rle s a I " m E REG. S24.95 SALE S18.95 en ' 1 ~ :z ~ SAVEUPT050% ON NEW PARTS I : ~ I ~ REG. $20.00 f;; ~ SALE $13.88 ~ REG. $ 8.95 ~ ~ SALE $ 3.88 ~ Do I en ...I W W :z:: :I: I PARTS FOR ALL MODELS RE G S 8.95 . ~ itl ,~I =~;;;cy~fz ~ SALVAGE 'tJ ~ 835 W. FO OTHI LL AZUSA 334-5912 en III ::::I :z:: ~ WE SHIP COD ANYWHERE TI RES TUBES ~ en HELMET a pounds. Should the user wish , he can . interchange the drive s quare of the two wr enc hes to pr ovide grea ter fl exibility of applicati on an d wider use. The s wiveling fea tur e of the r eplaceable dr ive s quare add s gr ea t versatility and convenience to these ne w torque wrenches . it pe rmits, for exam ple, usin g the torque wr ench as a fle x handle for s tarting and r unning cylinder head bolts down prior to torquing them. Als o, when applying torque to a bolt or fastene r , the wr ench beam can be " flo ated" up an d over or below obs tructions without arfecti.ng the. accuracy of the torque indi cati on. In addi tion. the s wivel head fea- ture per mits the us er to reach and tor que narc- to- r nach studs , nuts, etc . by fli pping the drive up or down to the mos t conve nient pos ition. The new Adapt- O»Flex torque wrenches also feature the flo ating han dle design requir ed to Insure accurate tor quing with adapters. Each wr ench has a dual directreading scale. The Inner scale permits direc t r eadings when the wrench is used with 1-1 / 4" lever length adapters . The outer scale gives torque values when the wrench is us ed without adapters . The manufac turer states that the newwrenches are now avallable fr om most leading tool suppliers.