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/125841
ASK • - 10 circli p s an d d ealers sometimes forget to ad vise y o u to replace them. The clip ma y look good to y ou , but is it ? Look ver y close and yo u will see a wear mark where the p in has been rubbing on it , plus when yo u t ook it out you probably bent It just a little . It 's en ough to keep th e clip from sea ti ng in the groove. I don't need to tell you what happens if the clip co mes out. If you're on the fre eway go ing 70 you may lose a lot more than just the engine. Do a get-off on asphalt and it takes a long time to heal. Take the new clips and cu t the end off. Leave just enough to get hold of with a pair of needle nose pliers when you have to replace th em again. Always ins tall the new clip by hand. Use you r thumb . I know it hurts but if you use pliers, you m ay bend the clip which wiII ruin it . The reason for cutting the ends off is th at under high RPM operation, there is a frequen cy of vibration that sets up in th e cli p an d causes the end to snap off. PUCH.ing I have a 175 Puch and t he re is a lot of engine noise co ming from the cy linde r. Th e bik e isn't very co ld. Do y ou think it needs boring already? R oger Cosio Lawndale, Calif ornia I've seen new en gine s worn o u t in one day becau se of improper air filter servic ing . If you're in d oubt about wheth er dirt go t in , pull off th e t op end and mik e th e cy linde r. Look very closel y a t th e bottom of the in take port. T his is w here the mo st wear shows up. Any dirt that co mes through the air filter wash es down th is part of th e cy linder wit h t he inco ming gas charge , ca using this to be the highest poin r o f w ear. T he cy lin de r sho uld mik e o u t to under .006 inch w ear. If it doesn't, then it 's time to bore it. If the cy linder is O K, th e engine noi se co uld be from fin vibration. You can eliminate some of it by cu ttin g a co u ple o f rubber bands about an in ch wide out of an inner tube and stretching th em over the head . Plug life I j ust bou ght a 1972 360 Yamaha Enduro and I can 't see m to get more than 30 to 40 miles on a spark plug. The air fi lter is good and there is no dirt coming through it. J im Anderson West Los Angeles, Calif Wherein E.C. Birt hisso~self ansW'ers the Blind-boggling questions you ask. Multi-Vis I recently bought a new Honda 750 Four. The owner's manual recommends either lOW - 40 W or 20 W-50 W ail. The shop I bought it from put in straight 30 W. I'v e go t a case of straigh t 40 W sitting in my garage and wo uld kind of lik e to use it. What are the factors that I should consider in d eciding what t o do? Virgil T. C in ne a Buena Park , Calif .. • 32 Dual purpose o ils, lik e 10-40 o r 20 ·50, are recommended be cause when the engine is cold , the oil is in t hc 10 IV sta te of visc os ity. As the e ngine wa rms up and gets hotter, the o il th ick en s up and holds its high est visco sit y rating o r very close to it. As to why th ey pu t 3 0 IV oil in, I really don 't know. The 3 0 IV won't hurt anything if y o u let the engine warm up good before riding. After you get going, don't j ump o n th e freeway and run nat o ut fo r a long distance as the oil will tend to thin o u t, so the engine will be hard pressed to live very long. If you use the 40 Wail, it will take a lot longer to warm up. If you don 't run it long enough to thin out yo u may blow an oil lin e or cause sea ls to start leaking due t o the inc reased oi l pressure. Your new YZ has a very good set of forks. They have co me a long wa y from th e old 125cc o f y esterday. Use only a go od brand of fo rk o il in 10 or 20 weight. For TT racin g, or if you like a s t i ffe r fr ont end, u se 3 0 W. Multi-viscosity motor o il will n ot work to o w ell be cause it will foam. But you d o hav e a wa y au t. Most o il com pa nies make an o il th ey ca ll turbine oil. Ir' s a little hard t o ge t hold of bu t you ca n bu y it in 10 , 20, 3 0 or 40 weigh t. T hen yo u can mi x your o wn o il to get the ult im ate fro n t e nd damping. Honda spends thousand of d oll ars on research and development and, not to poke fun, I fell they kn ow more abo u t their engine than your de aler. Ano ther thing to remember is that you have vio la te d your warran ty by not fo llo wing the owner's manu al re c ommen dation s. Which mean s yo u brea k, you pay. Do wh a t th ey tell you and if it breaks, they will pay . Fo r Ca lifo rnia rid in g, I wo uld usc 20W-50 W becuse it's ha lt er here . If yo u live in a co lde r area, use I OIV-40IV. Use yo ur 4 0W for chai n oil. I I I I I Fish oil ? Is it better to use multi-oiscosity or single viscosity oil in the forks of my / 25 Yamaha YZ? T homas D. Richards Lombard, lllinois i Fo rty centavo s I have a 250 Yamaha twin and / bought new pistons and rings for it but didn 't get new circlips. Can I UJC the ones th at w ere with it already? They look all righ t to me. J im Mey er San Pedr o, Calif, ! ' Don' t 10 "ce n ts ! cheapest I take a cha nce. T hey only cos t and th at 4 0 cents tota l is th e ins ura nc e yo u will ever buy. Some ne w pis to ns do n 't come with If your jetting is good, then I thi nk you might be the victim o f an electrical problem. AC ma kes a spark plu g tha t seems to hel p . Ask yo ur lo cal Yam ah a dealer for them. Boil ing over I have a 1973 175 Penton [ackpiner with th e Bing carbo I'm an enduro rider and wh en I hit a long straightaway or run th e bik e hard, th e gas boils out of th e carb and it won't restart. I've done all th e usual things lik e jetting, timing, etc. I have t wo buddies that ride with m e on Jackpin ers and t he y don't have this problem. Ja ck Huffman Titusville, Florida Jack, I've heard of this before and see you've done all the usual things to cure it . The problem may be in the intake manifold. The manifold, as you know, has no heat block between the carb and manifold throat. I'd do two things. First, wher e the manifold bolts to the cy lin der , put in one more packing gas ke t, To be sure it seals good so you don ' t ge t an a ir leak, put a coat of gas ke t c inch between the m. Se cond, lurn the en d o f t he manifold down and mak e a n ylon bu shing that fits in the carb o (Or yo u can bu y th e bu shing fr om Precision Cycle, heh, heh .) This bushing will ke ep t he alu min um body of the carb fr om bein g rig h t agains t the aluminum of th e manifold and the carb then w on't a bso rb th e engin e heal. Any tr ick y (o r trick) quest io ns to E.G. Birt for I h is colum n shou ld be ad dressed 10 " A sk E.C... , c/o Cycl e News/West, Bo x 4 98 , Lo ng Bea ch, Cal ifornia 9040 I .