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/127684
Kawasaki KX250 off-road conversion By Chris Jonnum Iii ~ hen you really th ink about it , I.I}) Kawasaki Team Green's off-road policy is a little weird. They hav e what is arguably the most talented collection of riders around, and they spend a ton of money on the ir race program. Though championships are somewhat rare for the green team (because they tend to hop from series to series), race wins are common, and most ama teur off-ro aders dream of ri di ng for the famed squad. But there is still one problem; Kawasaki d oesn 't sell th e bikes they race. Sure, it's not a difficul t task to find a KLX four-stroke on a showroom floor, bu t the majority of Kawasaki's off-road success comes on the sa me bik es tha t bring most of their motocross success their KX lineup. Kawasaki doesn't sell a competitive 2S0cc off-road tw o-stroke, so team riders mod ify MX bikes for the rigors of off-road. This may seem a little strange, since Ka w asa ki can ' t really advertise a closed-course-only motorcycle as an off-road bi ke, bu t ap parently enough people get the messa ge on their own. We di d, and d ecid ed to modify our '94 KX2SO in much the same manner as Tea m Gr een 's Ty Davis, last yea r's top American in th e Dutch ISDE and third-pl ac e fin isher in th is season ' s Na tio na l Champ ionsh ip Re li ab il it y End uro Series. I WANNA BE LIKE TV o Our bik e is not an exact re plica o f "Zip Ty's", but many of the major components are similar. Unlike Davis, who must remain loyal to his sponsors, we ha d the luxury of going to any company we chose . Still, we tried to avoid going on a spending frenzy, instead concentrating on changes we felt were importa n t. The one area where we really splurged was with the for k, wh ich we replaced with Marzocchi's much-talkedabout conventional Magnum unit. "The KX's Kayaba fo rk is the best stocker around ," we can hear you saying. "Why mess with a good thing? " That' s ac tu ally a good point, but Dav is uses the Magnum, and bes ides, w e w e re curio u s to find out ho w it wo u ld work o ff- roa d. We w er e impressed with the fork's performance on a motocross track, but after seeing Davis, Kevin Hines, Scott Plessinger and Jeff Russell use the Marzocchi with much success off-road, we approached Stig Pettersson of Pettersson Pro Suspension (the U.S. Marzocchi importer), and asked him to dial our fork in with Davis' settings. Pettersson was happy to ob lige, enlarging the oil holes in the shock's p iston and al tering the shim stack. A 4.5 spring replaced the standard 4.0 un it. We also imitated Davis by slipping the fork into a set of custom triple clamps, CNC -machined from billet aluminum. The clamps ar e ma nufactu red by none other than Ty's father, Te rry Davis, owner of Terrycable. Terry felt that the stock bike tended to "hun t" on straights, and was affected too much by variances in terrain. He also thought the front end wanted to push in turns. His sol u tion was to stee pen fork an gle by one-h alf a degree, which also shortened the wheelbase by app roximately a quar - ter of an inch. Tha t decision may seem a little od d, considering the fact that the KX is considered to be a quick-handling bike, bu t Terry claims that what works on pap er doesn't always pan out in the real world. We needed to ha ve the shock revalved in order to match the endurofocused Marzocchi fork, so yet again, we copied Davis by going w ith L.R. Racing. Davis - and obviously Larry Roeseler himself - both utilize the tuning abilities of L.R. Racing suspension guru Darrel Prieur . Prieur valved our s to ck KX shock specifically for gnarly off-r oad use, taking out some of the high-speed compression and - to minimize squat adding low-speed compress ion. To make the bike " soak up the square-edged hits so co m mon on techn ical tra ils, Prieur also modifies the shim stack in the compression adjuster. The stock spring was retained, and Prieur say s the rate is fine for riders up to 190 pounds in weight. Though much improved over the '93 brakes, Kawasaki's bind ers are still not up to par with Honda, so Braking Brake Systems set us up wi th front and rear oversized brake kits. The kits includ e la rger rotors, d iffer en t caliper carriers and rep lacemen t brake pads. We also opted for Motion Pro cab les, including their longi tu d inally wound Terminat or clutch cable. We tossed our s tretched -o ut stock chain in favo r of Moose Racin g's new GPO a-ring chain, which is manufactured by Regina, and dr ap ed it over a pair of Answer Radialite sprockets. The s tock 14/49 gearing was retained . We never had to adjust the cha in. Davis is sponsored by Dunlop, but we were in the mood for something different, so we p u t in a call to Mon ar ch Tire Company, the American importer for the Swedish-man ufactu red Tre lleborg tires . Monarch supplied us with a se t of their medium-terrain r ubber, which consisted of a Super Grip Extra front and a Ten Masters rear. We also decided to go with foam tire in serts rather than tubes. Tech Products was happy to oblige, dialing us in with their new Tech tubes. We didn't go crazy with the motor, feeling that its broad spread of power was already clos e to perfect. An FMF Gold Series pipe was bolted on, and we went with a Wiseco Pro-Lite pis ton kit when it was time to rep lace the top end. The assembled Wiseco piston is 15 grams lighter than stock, and is forged instead of cast. Each kit incl udes a piston, wrist pin and circlips. A Uni Ultra Seal air filter wa s also used, a nd a n Acerbis 035 plastic silencer handled our spark-arresting chores. " Most of our off-road test riders are on the tall side , so Ceet su pplied us with a taller sea t-foam chu n k, w hich w e wrapped with their non-slip Dynotech/ Ke vlar sea t cover. We also m ou n te d Answer's jolt-absorbing Pro Taper handlebar, going with our p referred Suzuki bend. Ex te nd ed fue l r ange is always a necessity for off-roa d, and we used two "different options to sa tisfy the green machine's thirst, depending on the cond itions. When we reaIIy had a long way between gas stops, the huge 4.4-gallon IMS tank was our choice; otherwise, we went with Moose 's trick new 3.3-gallon fuel cell. Built for Moose by off-road en thusiast Lindsay Pirie, the tank 's bottom half is made of Kev lar, w hil e the top is built from ca rbon fiber. Ma ny of th e mo ds we mad e wer e sim ply aimed at protectin g ou r beloved KX from the bru tal conditions we knew we'd be su bjectin g it to. We insta lled an L.R . Raci ng wa ter-pump g uard and chain guide guard, and strapped an Acerbis plastic pipe guard on the fresh new expansion chambe r. With a Viton rubber insulator at each of the mounting points, the plastic is able to withstand the h igh temperatures encountered. Motion Pro pedal anchor kit s p ro tect both the s hift and rear bra ke pedals from errant foliage, and Ace rbis Rally plastic handgu ards (with spoilers) proteet our precious digi ts, Acerbis' purple radiator shrouds and fenders we re bolted up to give our bike a d ifferen t look, and a plastic brace suppo rts the fron t fender. Acerb is also supp lied a pl astic, fol d -down mirror, as well as an Elba 2 headlight and battery pack. Ce et Gridlock rad iator sh roud graphics round out the appearance. MEAN , GREEN WOODS MACHINE We put a lot of riding time in on our project KX throu ghout its evo lution. The bike has s u rv ived two N ation al endures, MXs, gra nds prix and beach ra ces, but we need ed a good forum to try ou t the fina l version. Wh en Moose Racin g gave us a call , inviting us to a week-long press introduction of their new clothing line, we knew we'd found it. Held in the mountains of Colorado, the trail ride included everything from gn arly single-track to rocky fireroa d s,