Cycle News - Archive Issues - 1970's

• I ? r--C'J >-CI:l ~ r By John Ulrich • Up until a few weeks ago, the TM 125 was Suzuki's only 125 class motocrosser. In the context of its racing class, the TM is an econocro sser, giving away horsepower to other popular Japanese 125s, but often' sellin g for hundreds of dollars less. 24 As recently as three weeks ago, motorcy cle shops were advertising T lIl 125s for as little as $69 9 b ase price in California. (List price is S8 15. ) That price tag mak es the motorcycle an exc elle nt buy for anything short of serious m otocross racing. Th is Suzu ki, in sp it e of its name , ma kes a be tter de sert an d play bi ke than it does racer. Even in the 12 5 Beginn er clas s a t a Saturday NIX in Southern California, out-powered by t he TM was th ree -quarters of a 19-b ike field. No m atter how fas t a rider is o ff th e line , no m atter how accurate his shifts, a lo ng start hill will still favor a com p eten t rider o n a faste r m achin e. The TlII 125 is just not co mpetitive. No w the TlIl has some new co m petition, in t he fo rm o f the R.\I 12 5 a m otor cycl e Suz uki S uz u ki, re p rese ntatives say will no t -replace th e TM this year, but rather su pple me n t th eir m o to cr oss lin e fo r the serious racer. The battle t o get in fro nt an d stay in front of th e faster bikes in th e 125 class has driven man y TM owners t o add ing trick head s. n on-stoc k piston s (some use cu t TS Suz u ki p istons ), and port ing jo bs. Conscious of th a t fact , Suzuki makes a big deal o f th e new port ing used in th e RlII engi ne . 111is new p ortin g provides n ot only a five-horsepo wer gain o n the t op of th e powerband, bu t a broader, flatter torque cu rve as well . The R.M:s p ower ch ar acteristics fit its five-speed transm ission better than the T M's power ch ara cte ris tic s fi t th e same t ran smi ssio n. Th e T:'I is harder to ride than the RlII be cause it is harder t o keep th e TlIl on th e powerband. It ' s a good thing th e TlIl has a great cl utch for just th at reason. Slipping th e clu tc h and keepin g th e ride r 's wei ght o ver th e gas tan k keep th e rear wh eel spinning and th e motorcycle movin g. On ce th e rear wheel stops spinnin g wildly an d the engine falls off the powerband, it is either slip the clu tc h or st op, espe cially in m ud or sand. The onl y time th e clutch ac te d up an d go t grabby was after several attempts t o climb a st eep, rocky, san dy de sert hill a fter turning 90 degrees out of a canyo n. Without momentum t o help it up, the TM co uldn ' t reach the top without ab using the clutch and pushing. Both the TM and th e RM sh are a front fender that does a good job of keeping the h ead and cylinder fins from packi ng up with m ud. The RM goes a step further with a m ud flap to stop m ud thrown o ff t he front wh eel from fly in g up to hit the rider. Both have we ll padded sea ts ; the RM 's is best. Bot h h ave the same footpegs , with tr action bumps not big or sharp enough to wo rk well in mud. Both have gas t anks th at are nice and narrow for standing up or sliding forward, yet hold enough fuel for a 40-minute m o t o, And both prove that someone at Suzuki has a soft spot in their heart for small diameter, hard-to-see-what -you 're-d oin g gas caps. 111e TM also h as an oil -injection t ank tha t holds en ough Cas t ro l R for six 20-min ute m o tos, and w hich has a ca p so small and so oddly-pl aced th at it is eas iest to fill th e oil tan k wh en th e bike is standin g vertical on its fron t wheel. (A win ch on the garage wall speeds th is mai n te nance ope ra ti on. ) The RM dispe nses with th e inject ion tan k, usi ng pre-m ix in the gas tank, an d th e save d space to acc o m modate the relocated shocks. Alon g with a lar ger d iam et er, increased travel front fork , th ese reloca ted (and redesigned ) rear shoc ks mark the com plete ab andon men t o f T:'I suspens ion in th e desi gn of th e RM. The T:.t's suspenders work reas on ably well , the bike ne ver doing any thi ng un expected or o u trageo us. It is a fo rgiving m otorcy cle. Giant di ame te r shock ro ds di dn 't bend or bre ak on the TM , but the rear end is bouncy. The fork to ps out, su ffering, like the rear end, fro m too m uch spring. RlIl suspensio n co m p o nen ts are designed with t he T:' I's faults in mind. Fo rward mounted , well b uilt an d p ro te ct ed gas /o il shocks on a beefed-up swingarm work wonders for th e rear en d . Lar ger fo rk tubes and sliders with increas ed oil ca paci ty st re ngthen th e fron t end. Rough sec tio ns of track are easier to ride qui ckl y on th e RM than o n the TM, and rear-wheel b ounciness is reduced o ve r whoops. . Bra kes on both bikes ar e o uts ta ndi ng. On both, th e ride r m ust exerci se care to see th at th e throttle housing is positi on ed sum that it s widest part is not in lin e with the pull of th e fro n t brake lever. If it is, th e fron t b rake lever can bottom o u t on the twist grip cas in g befo re all th e lever t ravel is used up. Racin g on a very mud dy, slo ppy clay trac k where th e only fast lin e soon became a trench p ac ke d in to t he adobe an d goo, we foun d it difficult t o put t he T M's fro n t wh eel where we wanted it. Riding out of th e tre nc h m ean t either losi ng substantial sp eed figh t in g th rough cl um ps and sla bs o f mud left fro m pre-race t rac k pl owing, or else disappearing in a qu agm ire . Staying in th e trench meant going slo we r th an we would have liked in some sec tions to keep fro m cat ch in g th e sid e 0 f th e gro o ve and fallin g o ver o r cl imbing out. Picking a' precise lin e is mo re di ffi cult with the TM than with th e RM. Suspension h as a lot t o do wi th t ha t, and th e tires ar en 't th e best mudders . either. Not t oo surprising t o anyone but a dry-ground Southern Californian, the TlII is skittery in mud. So is th e RlII. And. p robably, so is an Elec t ra-Glide. What to do ? You 've got a TM yo u like , and yo u want all the new RM tri cks. The best move probab ly is to buy an RM. If you can't or won't do t hat , buy RM susp ension yo u can co m p on en ts and install th em. The front end with triple clam ps will bolt on , as will the swin garm . Mountin g the shocks will require a welding to rch an d some me asurements availa ble from U. S. Suzuki. That last modification will also 10 Coming off an uphill st art ing area, the TM works as hard as it can. It 's just not hard enough to beat the competit ion. 6 7 8 RPM 9 10 11 RPM x1.000 What the RM 125's trick porting really means. require the rem oval of th e oil inje ction syste m, pluggin g of case o il-line entry passageways with small bolts, and taking o ff th e crank bearing slinger pl ate, whi ch dir ects inje cted oil an d sh ields it fro m incoming fue l ch arges. 11,e R.\I top en d will not bolt right on the TM engine; th e cy lin der and he ad bolt p attern is differen t, and the RM's lar ge tr ansfers would not m atch u p with TM cases anyway. Getting more horsepower o ut o f the T M means working over what you 've got o r buyin accessory equipment. With the suspension work, and en oug h mone put in the engi ne, it is possible to put TM ba ck in the hunt. But c onsidering th at the RM lists fo $925 , just buying one already tricke out doesn't sound like a bad idea.

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