Cycle News - Archive Issues - 1990's

Yamaha 540 dirt tracker, part 3 By Scott Rousseau ast week w e laid th e fou nd a tio n nece ssary to make o u r Yama ha flat-tracker tum like a cha mp. This week we concentrate on giving the bike a reason for needing to handle as well as it does. Yep, it's engine building time. With Anders Racing Products completing the hackwork ~m ow: chassis, we shipped it over to Matt Hilgenberg of Speed and Sport in Long Beach, California. Many moons ago, 01' Hilgee was an editor here at Cycle News. And not one to tum away from cool projects (tho ugh he is probably busy eno ug h already), he offered to throw in his two cents by m aking su re th a t our frame, the Sun ri ms that we bou ght fro m Buchanan's Spoke & Rim and the hubs supplied by Johnny Isaacs were po wder-eoated . We wanted the bike to look nice, altho ugh it p ro bab ly w ould have looked just as good wi th the aid of a few spray cans and plain silver rims and hubs. Oh well, keep in mind that there are places where you can overindulge if you want to. That said, we d idn't underestimate the value of a good-ru nning engine for our project bike, and we knew just the guy who could get it don e for us, so we sent the motor packing to Isaacs and his Total Performance Racers & Restoration shop down in Tulsa, Oklahoma. A former National number holder and multitime na tiona l champion in the Vintage Dir t Track Racers Associa tion , over which he also used to preside, Isaacs is a lso an ace w hen it comes to building com plete vintage d irt trackers . Altho ugh Isaacs specialize s in the preparation of Brit ish -heritage racing twi ns a nd si ngles, the Yamaha XTITT sing le has been the motor of choice in the VDTRA 600cc Pro ra nks for several yea rs now (it has n ow also be com e pop ula r in t he AHRMA '70s Singl es category). Isa acs ha s go ne throu gh quite a few o f the Ya maha si n g les in his d ay , a n d, L ocr 1l E ., u ., C 16 li ke Rick And ers , b e li eves they a re quite capable on most small tracks at the sportsma n level. "Even up to certain half miles, depending on the track condition s, the Yamah as are go ing to be just as competitive," Isaacs says . "Na tu rally, in all-ou t horsepow e r, a four-v al v e e n g ine is goi ng to mak e more th an a two-v al ve [such a s th e Ya ma ha ]. but d irt tr ack d oesn't necessarily d epend o n all -ou t horsepow er beca use you are ofte n rid in g in less than id eal track conditions. The Yamaha is capable of a d ependable 50 horsepower." Dependability would ha ve to be a ma jor factor in ou r mot or, as severa l Cycle News ed ito rs and ad guys were al rea dy taking a numbe r for a spi n on the bike when it was comp lete. Also, the idea is to be riding yo ur bike, rather than wrenching on it. Keeping tha t in mind , Isaacs put together a sensible list of the parts that would be required to tum our motor into a short-track hero, turned us loose, and then went about the stan da rd teard own and inspection procedure. "Basically, yo u r eng ine showed the norm al road mileage an d wea r," Isaacs recounts. "It didn't look like it had been abused or anything. It was just a matt er of going back and fresh en ing everything up." On e area that Isaacs does pa y particular attention to during the teardown is the inspection of the cylinder base stud s and correspondi ng holes on the barrel. Be carefu l that ther e is no elongation in the cylinder holes - that mean s trouble a nd is a sign of a h amm er ed mo tor . Isaacs says that 99 p er cen t of the time the ho les are perfectly rou nd, ind icating a prime cand idate for a rebuild. The crankshaft appea red to be in good spirits, alt hough it was pressed apa rt to accept a new rod kit, which we go t from Ya ma ha but is availa ble through you r (Top) Total Performance Racers & Restoration's Johnny Isaacs puts the finishing touches on our Yamaha 540 dirt track engine. As old race motors go, Isaacs likens the Yamaha to a perfected BSA Gold Star. (Above - left and right) Special machine work was kept to a minimum. It included machining the right-side cover to accept the right-side shift, and the openingof the valve seats to accept "SR-style" valves. local Yama ha dealer. Isaacs recommen ds go ing one of tw o wa ys her e. A Carillo rod is the ultimate. It is rebuildable an d will guarantee a motor tha t can be taken to hell an d ba ck even on a mil e . Th e stoc ke r lasts jus t as long in shor t-trac k co n d itions, a n d you ca n repl a ce tw o Yamaha rods for every one Carillo. othe r ca ms tha t ma y make better pea k pow er, bu t Isaacs sa ys tha t th ey ca n be an inv ita tion to trouble in more ways than one. . "Some of the more rad ical cams may make more pow er on top , bu t you lose that bro ad p o w erband ," Is aacs says . "Thos e mi ght make for a g re a t dra g racer or road racer, bu t not a great dirt track er. Again , there is only X am ount of . hor sepow er tha t yo u can us e on a dirt track." We al so wen t w ith re co nd itione d roc ke r arms - a must w he n replacing cams - and an R/D tit anium sprin g kit to make sure tha t the valves nev er go t to meet the pistons 'd ue to float. Besides bo ring the cylinder, the only real mach in e w or k th a t need ed to be d one to the eng ine involved the relieving of the piston so that it wo uld clea r the new Yamah a SR valves tha t Isaacs elected to run. Th e s tre et-or ien ted SR va lves are slig h t ly bigger th a n th e Cometic Gasket Total Performance Racers & Restoration f5767 EastAve. 6710 E.lst Pine Mentor, OH 44060-4303 Ph:216/974-1077 Fax: 216/ 974-9135 Tulsa, OK74115 Ph: 918/836-6999 Fax: 918/8J6.0099 Head and basegasket $22.95 Megacycle Cams 90 Mitchell Blvd. San Rafael, CA 94903 Ph: 415/472-3195 Fax:415/472-1497 Wise co Piston 25162 cnmshaft Ib illet) $159 .. .. . . . .. . . . . .. .. .. . . . . . ... .(hardfaced) $98 Rocke arms r $49 ea. RIDSpring Corporation P.O. Box 403191 Hesperia, CA92340 Ph: 760/948-4698 Fax:760/9 48-4856 Titanium valve spring kit Engine rebuilding and balancing $400 Shifter conversion (magnesium cnses) $150 Front hub $140 Rearhub. bearings .$170 Airheart brakesystem, hangar etc s, $300 7201 Industrial Park Blvd. Mentor, OH 44060 Ph:440/951-6600 Fax: 440/951-6606 90mm piston kit ui] rings pin and clips .. .$117.50 Yamaha Motor Corp (Bob Starr and Terry Bea l) 6555 Katella Ave. Cypress, CA 90630 $91.41 Various OE replacement parts 0CtJ1 (Parts and pricing availabi<' Ihmugh your 1 Yamalta denier)

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