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/127716
end, it cou ld use more overrev , In orde r to m ak e the m ost o f th e cy li n der an d head modifications, Pro Circuit split the RM' s cases and matched a ll of its su rfaces. In addition, Pro circuit cut 15mm off the stock reeds in order to stiffen them up an d im p rove th ro ttl e response. A super-trick carburetor vent kit w a s installed on the rejetted Keihin (172 main. 52 pilot, 1469 need le at 2nd clip, air screw 1 1/2 turns out), that includes T-fittin gs, hoses and a sano aluminum canister that preven ts wate r from ente ring the carburetor d uring washings. A Pro Circuit Works Pip e and Factory Sound Silencer round out the eng ine package. Su spensi on m ods were next o n th e a genda, and that's where Jim " Bones" Bacon stepped in. Bones sim ply nodded and sm iled when we complained ab out the saggy-fee1ing rear end, then assured us tha t he cou ld remedy the problem . The first thing Bones did wa s replace the wim py stock 4.8 shock spring with a beefier 5.2 unit. Next, Bones dug into our stock valve sta ck and tightened up the "loose" initial settings. With the sag set at 95mm, we foun d that the shock wo rked best with the com pression set at 12, and the rebo und set at eight. Up front, Bones felt th at the stock .38 springs were sufficient, and relied simply on a few minor v alving ch a nges. O il heigh t wa s se t at 14Omrn, and after trying several di fferen t settings, we settled on compression at 10, and rebound at 14. With the tw o most important ingredi en ts - the mot or and su spension - handl ed, Pro Circuit d irected their attention to the rest of the machine. Ask yourself, what really sets a trick bike apart from the rest ? Atten tion to detail. In ad dition to offeri ng a wi de selection of hop -up se rvices, th e Pro Circu it sho w ro om a lso stocks a com plete line of accessories. One stop is all any wa nnabe racer ne eds to make. Th e stock s tee l h andl ebars were pitched in favor of a pair of Renthals.as was the stock rear sprocket for a 51-tooth Ren thal piece. Medium compound halfwa ffle Renthal grips were mount ed on the bars. A pair of extr a-wide Pro Circuit foot pegs rep laced the wi mpy stockers, and a one-p iece al u mi nu m handl eb ar clamp replaced the tw o stock clam ps. In ad dition to pro viding g rea ter st rength and rigidity, th e one-p iece clamp keeps the bars from twisting in m inor tip-overs. A Works Co nnectio n sta d ium s kid plate and fram e guards were bolted onto the chassis, and a Pro Circuit Ceet cove r and graphics kit rounded o ut our rep lica racer. RIP AND TEAR Once we wip ed th e d ro ol fro m o u r chi ns, w e were anxiou s to ta ke to th e track abo ard o ur " Ping ree Replica ." Fro m the m om ent we first fire d up th e bike, it was crystal clear that this was not the same machine we had handed over to Payton a few days ea rlier. Even in the p its, th rottle respons e was incredible the bike revved quicker an d much cleaner than it had in stock condi tion, and the bark emitted from the silence r sent chills up an d down our spines. Though th e n am e " Ba n s h ee " is alrea dy taken by Yamaha's perform an ce ATV, suc h is the best w ay to describe how the Pro Circuit RMl25 feels on the track. The bike is an ab solute screame r. We were concerned that the nice burst of low-end power would have been lost, and were relieved to find it still intact. Hit the middle o f the powerband, thou gh, and things really start to change. Th e RM ha s an in credible midrange su rge of power that pulls well into the upper limi ts of the rpm range. In th e 125 cla ss, the Hond a CRl25 engine is the standard by which all others are judged. A stock CR? No comparison . The PC RM is one of the hardest -hitting. yet easy-to-ride mod ified 125s that we've ever ridden. Unlike some hot-rodded tiddlers, the RM is easy to keep on the pipe, and doesn't require a pro rider in the cockpit. But don't eve n think abo u t running pump gas in this baby. We m ad e th at mistake and promptly blew the bike to bits. Sorry, Mitch. Luckily, Payton w as gene rous enoug h to rebuild our scoo ter, and we've been good boys ever si nce . (Above) Pro Circu it stocks a full line of Works Connection aluminum accessories. (Left)The Works Exhaust Pipe is available In both the tradit ional unpa inted (sh own), an d a new platinum series versi on. expected smooth ride, and as always, we loved the half-waffle-style gri ps. Without a d oubt, the Pro Circuit . Suzuki RMl25 is one of the most impressive 125cc project bikes we've ridden to date. In stock cond ition, the RM was the least favorite amo ng the testing staff, bu t is now the most sought-after m achine in the entire MX loan pool. To say that the s tock RM h a s p o tenti a l w o uld b e a n u nderstateme n t - all it needs is a little n.c. Pro Circuit may be reached at 4214 E. La Palma Avenue, Anaheim, CA 92807, 714/993-5400. Look at it th is way - if you' re w illing to fork out several hundred d o ll ars fo r high-performance engi ne mod s, isn' t it worth the three bu cks a gallon to maintain your bike's added muscle? Thou gh it required a bit of expe rimentation, we were ab le to completely dial in th e PC-modifi ed susp en s io n . Bones work ed magic inside of the Showa shock, an d th e tenden cy to sag under acceleration was comp letely eliminated. Thanks to th e addition of the stiffer sp ring and tighter valving, the shock is a llowed to ride higher in its ra nge of tra vel, and in turn p ro vide a p lu sh e r rid e over th e small stuff. Hard landings pose no th reat to the ride r, as the stiffer se ttings gobble up even the largest of hits with the heaviest of riders aboard . 0 , no one on our staff is a su percross racer, but the b ike performed admirab ly at every "loca l" tra ck that we visited . Than ks to th e m uch-im p ro ved rea r sus pe nsion action, m ore att en tion could be di verted to th e perform ance of th e front Showa forks. We never ha d any real complain t? about the stock forks, but then again - we were never really able to see how they worked because of the horrid rear end. We are curious to see how the stockers would perform when mated with the PC-modified shock, but sho rt of ordering up a ne w set of stockers or having Bones revalve our forks back to stock settings - it wo uld be impossible to find out. But why worry? We found the l~ (Right) J im "Bones" Bacon worked magic inside our RM12S's Showa shock. The once soft and saggy unit was transformed into race-ready condition. The rear end tracks straight and true. revised setti ng s to be to our liking right from the start. We ended up stiffening up the compression one click to better m atch the stiff rear end, but all in all - the bike is very well-balanced . No, our RM hasn ' t been transformed into a yellow Yamaha YZ, bu t it is definitely as stable as an RM can get. As fo r the rest of the machine, what can we say? Anyone w ho tak es a good loo k at the photos can see th at the bike was almos t too pretty to ride. But how do you test a skid plate? Purposely case it over a double? Thanks, but no thanks. As far as fit and quality of construction, it's hard to fau lt any of the products that Pro Circuit added to our machine. The wider footpegs are a god send upon hard landing s, and we' re su re that the skid plate has spared us a trip or tw o over the bars. The Renthal handlebars d elivered the 15