Cycle News - Archive Issues - 1970's

w.t ASKE.C. Back by popula,eJemancJ 51 11II -= ~e.e..: 11II ...:I g ~ g -e- -, { r-- O"l ...... ' T ~; ( ~. <.0 ...... ' , ., ..,'-. ·c · ' '';. . ~:"'.'J~ !. , I': . .. 'i: ' 0.. -c . By E.C. Birt E.C., CZ help !!! technlquel to become on expert Heres how the experts do it. New im proved second ed iti o n by t he same people wh o produced th e first ed iti on. Mor e p ho tos, better drawing, eas ier to understand. r---------- I copies 01 Escape by Trail Bike @ S3.50 [ includes postage & handling) _. . total I I I I I _ I I I I I I Name I I I I • CLI P AND S E N D - - - - - - - - - - " ' 1 Mdre~ Zip Allow t wo to th ree weeks for th e post office. Send chec k or money order t o : CYCLE NEWS STUFF, P.O. BOX 498, LONG BEACH, CA 9080 1 I .. I . Please pr int d ear1 . v • I recently pu rchas ed a CZ 250ce MX with which I am ha ving so me d ifficulty. 1. It tend s to load up .and t o foul plugs on starting. Som et im es when it s running. 2 . It looses f ire to th e plugs p eriod ically. Th e d ealers I have take n it t o all want to change: 1. Th e ultra -cold PAl. plu gs (stoc k) to ho tter NG K B8HC - or B9HC plugs. 2. Th e standard two plug magneto ignition to a 1120.00 trans ist or ignition sys tem , 3. Th e jlKOV carb to a 160.00 Mik uni un it. M y problem is this: Tho se Czech s hav'\ a good (great ) mac hin e. It ru ns and wins fo r t he m. Must 1 alt er and A mericanize mine t o get it t o p erf orm in this co un try? Or can you pu t me in tou c h wi t h a d edi cat ed Czec h mo torcycle mec hanic w ho has a gif t fo r ma king CZs go . When my CZ ru ns, no t hing can touch it. No w t he tri ck is to keep it ru nn ing. Den nis M cBride R idgecrest , Calif. All you CZ owners tha t feel as Dennis does and are lookin g ' for that "special me chanic, there is o ne who feels that the CZ does not need a ll that tri ck stuff and can make that scooter of - yours even better than the Cze chs did b y a cou p le of tri ck mods to the stock mag and a little super-tuning to the st oc k .carb . 0 learned's name is Di ck Dixson, owner and Chief Bottlewasher a t : Allied Cycle, 24601 Arch St., Newhall, Cal if. 9 I 32 I. Phone: There may' be room for beHer quality in our leathers but we can't find it. We're still trying though II BILL WALTERS LEA TH ERS BW U 805/259-535 O. 445 So. Victory Blvd . Burbonk. Colifornio 9 1502 Porting • (1) What is th e b est way you have f ound to deter mine ex ist ing por t timings. (2) Do y ou m easure time-area values of p orts on your p orting jo bs ? If so, what have you f ound to be th e best way of measuring th e p ort s to de term in e t im e-area. . (3) "A ngle area " refers to th e angle of the con rod in relatio n to th e horizontal cen te rline of th e cran k and area of th e p ort , doesn 't it? (4 ) Could y ou please rec com end som e book on porting, scave nging, e x p a n si o n c h a m bers, and f rame geo metry and susp ension. (5) How do th e fa ct ories. lik e Yamaha, tie th e coo ling reservoir in with the damping mechanism of th eir sho ck ? Doug Brow n Canoga Park. Calif. Send S3.00 lo r 256 col orful catalog w ith p age more than 5500 items. COMPETITION SHOCK ABSORBERS .. _ I ' II 30 • • • • • FIVE WAY ADJUSTAB LE CHR OMED & POLI SH ED DO UBL E DA MP ENI NG R EBUID ABL E ST REET O R RA CING . DISTRIBUTED BY Samm y T anner Distribu tin g 1721 3 R oseton Avenue Artesia . CA 9 0 70 I 2 13/924-2 II I Betor Forks and Shu ck s Mak e t h e D lj jl're n ce II ( I ) Grinding a mill imeter here and there wen t o u t with high butt on sh oes. > and you 'r c: very wis e to ask th is question . I'm going 10 stra y from this a nswe r for just a m omen t , A ll yo u riders lake heed o f wh at I' m a bo u t to say . II's n ot top secret speed tr icks, o r so mething th at should be kept fr om th e publ ic. II 's j us t pl ain fact s. If the bike sho p o r a p erson clai ms to be a tuner an d do porti ng wo rk as a b usin ess, the n he sho uld be ab le 10 an swer Do ugs q uestion. Just present your questions as Doug did. Make him prove it, by showing you layout sheets and records of past engines they have built. If you don't, you m ay be in the market for a new cylind er next we ek , because the one yo u jus t laid o u t your hard earned bucks to ge t ported m ay be worse than stock wh en you ge t it bac k. T here ar e two way s of laying out an e ngi n e. Some tuners use th e: total durati on method. In fact . most of them do. I use a d ifferent a pp roach to the problem . I ta ke everyt h ing o ff of top dead cen te r (T.D .C.) because these are the number s tha t I need to figure expans io n cham ber formulas from. And I beli e ve this m ethod is easier for the ave rage rid er to under st and. T h ree tools th a t y o u must have to do th is j ob with a re: I. Dial indica tor to find top de ad ce n te r, 2. degree wh eel, 3. a pair o f di al calipers , eit her metric or thousands o f a n in ch. This is wh y I use th e th ousandsths of . an in ch scal e over th e metric scale becau se when I make a layout, the di al is easier to read. I think they now have metric d ial ca lipe rs but I haven't seen any yet. I started o ff many moons ago using the thousandths scale because those were the only ca lipe rs you co uld buy wi th a d ial scale on them. A depth mike will work just as well but not as easily. . First step is remove the head, m ag cove r and mag, carb , and intake man ifold if it - has one . Set your dial indica to r up on the top of the cy lind er. Now brin g the piston up . to T .D .C . Mount your degree wheel to the end of the crank with " 0 " o n the degree wheel ~ at the top . T ake a piece of welding rod, grind a poin t o n it and wrap the other end ar ound one of the m ag co ver sc rews a nd tigh ten in place. Now tum th e engine over and .se t pist on at T.D .C. Set _ pointer over " O" mark on yo ur degree wh eel. Now, yo u' re re ad y to degree th e eng ine in . (2) Ye s, b y th e abo ve method. (3) Yes. (4 ) Giv e Webco a call. (Phone have a whole library o f t his type o f in fo rm a tio n and can tell yo u t he near est dealer where you ca n get th e bo oks. (5 ) Wi t h passagew ays that are pressure -sensitive and co n necte d to the main sho ck body. The pressure of the oil as the shocks works ca uses it to c irc u la te. 2 13·39 9· 77 26). They Shock ing moves I have a Su zuki TM 125 and havin g read a rec ent art icle in Cycle News, I'm ready to m ov e m y sh ock s forward. In the art icle it said 7.00 inc hes sh o uld b e th e ma ximum trav el limit on any motorc ycle. What would be th e maximum travel f or my bike ? How far would I have to m ove my shoc k s1 forward t o achieve th e maximum timit? I ha ve a pair of KONIS 12.9 inche s' lo ng. Will th ey wo rk? Patrick Hubbs Cudah y, Calif. Pat, y ou 'r e ge tting into something that is more than j ust a little bit hard to d o. I ad vise yo u to take your bike to someone who is ca pa b le o f doing it for you. Bu t if yo u want t o try and do it . yo u rse lf , he re a re so m e guidelines to go bu y. ( I) .50 in ch es before the tire bottoms o u t on th e frame or the bottom o f th e sea t should be maximum travel a tte m p ted. S tep I in making the mod is to take the springs off of sh oc ks and the rea r wheel ou t of the bike, not take y ou r shocks and hold th em up to the sw in garm , mark the swi n garm where you want the low er sh oc k eye . Now by co m pressing the shocks and "lOIding the swin garm up y ou can sec if you have enough room fo r the tire to clea r the frame and seat. Be sure th at you have 1.000 inch of trai l on the sh oc k or it won't handle right. The KON I sho ck works all right b ut not in th eir st o ck sta te . T he y will fade ver y ra pidl y, Mik e Ra cing Center, among o the rs, (Pho ne :1 I 3/866-33 9 0) has th e trick reservoirs fo r th e KOl'I S. Or y ou ca n go with t he new shoc k th at has been d esign ed by Arnaco people fo r thi s type of fra me m od . T hey co st abo u t $65. 0 0 a pa ir and arc guaran tee d fo r one year . •

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