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/128083
Yamaha 540 dirt tracker, Part 2 By Scott Rousseau can already hear it coming. May be by now you have take n a look a t the photos of our "bro ken down" old project Yamaha dirt tracker, perused your own machine and then nearly choked to death once you looked at the price list to see the cost of the parts that we used to convert our rustv iron to flattrack gold . Yes, our bike, 'w ith its dirt track fiberglass bodywork, gleaming paint and trick rear-brake setup, is an I been raci ng flat track and mo tocross in the Southern California area since the '60s, and he knows ITs. He has been performing flat-track conversions on the . venerable thumper since buying his first one in the early 70s. To this day, the EI Cajon , California-based fabricator believes that ITs are the hot setup for several reasons, especially when compared to some of the so-called "dirt trackers" that have been mass-produced recently by some of the smaller dirt bike ma nufacturers sis, we went a head a nd trucked th e engine off to Ande rs' shop to begi n the conversion process. The engine, meanwhile, was sent to Johnny Isaacs at Total Performance Racers & Restoration in Tulsa, Oklahoma . Like the teardown itself, most of the labor involved in modifying the chassis is fairly mundane stuff, according to Anders. It just takes a little time . "We cut the head, and we fabrica te a swinga rm," Anders says. "We cu t away all the ext ra tabs on the fra me. We have to mou nt a seat a nd [m a ke moun tsl for the foo tpeg a n d b r ak e pe dal. We ca n also move the shifter over to the right side of the engi ne. We can do this by goi ng through the cases, bu t for the low -bud get racer I wo u ld sug gest going throug h the frame itself. I build a mechanism th at stands right in behind t h e e ng ine , b e low th e all th e di ffer en ce bet w een a bi ke tha t co rne rs o n r a il s a nd o ne t h a t flo ps around like a dea d carp when bent into a turn. For that reason, Anders is somewhat guarded when pressed to divulge w ha t he considers to be the ideal rake for his own chassis conve rsion . Even so, he is willing to give do-it -yourselfers some solid ballpark numbers. "If a guys sets up between 24 and 27 degrees, he should be okay. ot everyone wants it to be the same, anyway. Tha t 24 works well for real tight tracks, wh ile a 27 will be mu ch more stable at hig her speeds. I've come u p wit h wha t I feel is an id eal nu mber for most guys, bu t rid er preference can come into it." With the neck cu t off and reweld ed at its new angle, Ande rs turns his attention to the sw inga rm, which is perhaps th e second most important p art of the process, and a lthough Ande rs recom- (Left) The eas iest part of any pro ject bike , the teardown. (Abov e) Rick Anders of Anders Racing Products begins the transf ormation of our chassis. A complete rework runs about $1000. 30 example of how far you can go in building a competitive budget-racer. But the nea t thing about converting a IT is that you can take your time and, with the right ap proach to the project, spen d a littl e bit o r a w hol e wa d to make the machine as nice as you like. Heck, I'll ad mit it: I have go tten my butt w hipped by guys runnin g ITs or XTs wi th nearly stock engi nes, stock tanks a nd th e origin al front an d rea r hu bs laced up to 19-in ch hoops. In fact, the first su ch TT th at I ever ro d e was no more tha n just th a t - w ith a wo rn -ou t stock motor .to boot. But I ha d a great time on the bike because it featured the key ingredient tha t is a must if you are going to ge t a stock-framed IT or XT to act like a more exotic knig ht or cham pion. That' s where Rick Anders of Ande rs Racin g Products come s in. Anders ha s "Lets face it, a Rotax is a far s u perior en g ine th a n a TT500, b u t w hat yo u ga in in motor, you lose in chassis becau se you can' t use the power of these factory produ c ti on dirt tr a ck ers - th at ' s wha t they're calling the m, bu t they're really jus t motocro ssers with a few cha nges," Ande rs say s. "In ter ms of bang for the bu ck, you still can' t beat a IT500. Over th e y ea rs I'v e co me u p w i t h a few changes and inn ovations that I have perfected on them ." First, w e ha d to di sa ssembl e ou r stock XT and get it read y. The teard own was prett y straig htforward, as our bike had a t least been garaged, which meant that no fasteners were frozen into place. After yanking the motor ou t of the chas- swi ng a rm pi v ot, tha t turns it into a right-side shif t. " If a gu y is b ri ngi ng m e a rolli n g chassis, and I stay on it diligentl y, I can d o th e whole th ing in abou t a week," Anders says. From the time that I get the ro lling chassis to the Hm e that it goes ou t th e d oor is abo u t seven w orking da ys." Anders usu ally start s off by rem oving the rear fra me loop so that a fiberglass seat can be used , and grindi ng the steering stops down a bit for mor e turning rad ius. But the neck and swinga rm are th e key in gredients to th e wh ol e concept of set ting up a IT or XT for flat track use. In orde r to make the machin e handle, the steering head mu st be cut off and rewelded to alter the stee ring geo metry. This is the sing le most importan t step in the entire process, and can make mends that you bu y one of his len gthened steel or cromoly units, the stocker can be mad e to wo rk if you are willing to weld on axle pla tes th at w ill a llow you to pull the rear w hee l back abo u t one inch further. We went with an ARP unit, but p erhaps th e most inte res ting thing about eith er choice is that the rear geo m e try is su ch tha t 14- 14 .5- inch sh ocks can be utilized . Conventional di rt trackers use much shorter shocks, which is the giveaway that this is one of Anders' cost-cutting man euvers. "That length of shock is easy to come by," Anders explains . "When you s tart going to the shorter shoc ks, they have to be spe cially made. A lot of your olde rvin tage motocross bikes us e 14.5-inch shocks, so if a guy is low on money and can't afford a set of Works Performance or Progressive shocks, or if he has an