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/126008
KTM 250 MX: You don't need to know what' it means, just ride it By John Huetter with the assistance of Gary "Skyshot" Hymes & "Smilin' Jeff" Wright In 1974, a littl e factory in th e Austrian town o f Mattigh ofen built a bi ke th at officially won th e 25 0cc Motocr oss World Championship. On e result was ads, p ost er s, and stickies th at said " KTM **Weltm eister " appearing allover the world, excep t in the U.S. where th e same m achines wer e usually cal led Pento n s. But J ohn Pen ton 's main thrust has never been in motocross. It h as been in th e surgin g gro w th an d status o f Two Day an d Six Day Trial riding. Still , there has bee n a sub tle underground o f KTM fre ak s, u su ally n o m ore th an one or two at any race , wh o latched on to the 250 eng ine wh en it foll owed the 17 5 into this country as they discovered th at it powe re d o ne of th e fast est, bes t handlin g race bi kes of any type eve r built an ywhere . Th e KTM 250 set new st an dards of acc elera tio n in its class and was the firs t 250 with a six-spe ed gear box (wh ich m ost American ri ders didn 't understand how to use - too many choices). When we started this riding adventure it was with on e of these underground bi kes , the personal machine of Gary-Hymes who has be en on and off an d on KTM s since their in ception as a 250. ,By the tim e we fin ished o ur ridin g, i t was on the sponsored KTM of Jeff Wright. The fac tory is quick with im provements and the ch ang es in the machines reflected it. In fact, what we 'd like to tell you about is our experience with two different KTM machines, three different cylinder-pipe co m binati on s and a lik e num ber of su spe nsion matches all of wh ich, for better or wors e, have been typical KTM. Th e KTM works is nearly falling over itself in th e speed of its development cy cle an d th ey don't wait for the new model year to inc o rp orate changes on the production line. The buy er reaps the benefits in an incredibly short period of time and, curiously, we 've never h eard an y 250 KTM devotees get upset be ause th e bike they bought three m onths earlier has beenquietly superseded by a new, different m odel. Tolerant and understanding bunch . About a m onth ago, all KTMs imported in to the West ern U.s . began h avin g "KTM" logos applied to the tank as well as stam pe d in the engine case s. In the Eastern U.S., "Pen to n " will still appear on the tanks. Th ough act ive in th e ISDTwhen it was st ill a meaningless garble of initials to most Americans, Western distributor Ted Lapadakis has since de cided to put the emphasis of the KTM s called "KTM" in racing rather th an trial-enduro competition. (Rem ember th at the "Penton " enduro h as been n othing more than a motocrosser with a lighting kit for so me time.) 36 This direction has resulted in so m e rather su btle changes to sp eci alize the KTM 250 a little more for ea ch application. Th e KTM Enduro avail able to West ern end uring types will be little ch an ged, except for improved suspension. The m otocross ma ch ine is more, radically ch an ged and all of it is for the better. The KTM motocrosslhas a new fram e which is margin ally lighter (They're already chro me moly steel. ) than the "s n o rkel " fram e of the en duro, but th at isn't its m ain advantage. The new frame, actually allows th e average rider-mech an ic to rem ove the cylinder head without taking the engine and pipe off and out of the frame completely. The backbone tu bes are smaller , o f m ore open co nstru ction and the seeming maze of gusse ts and equipment co nvo lutio ns th at m ad e the previous versions less than a joy to work o n (considera bly less) h ave been resolved into a m ere two engine sta ys. Th e fastening nuts an d bolts are even more acce ssibl e on th ese stay s than th ey eve r h ave been. Th e KTM on wh ich we st ar ted absorbing dat a h ad ei ght-inch Ceriani forks up fr ont an d hi ghly expendable Ceriani gas sh oc ks at the rear. The 250 on whi ch the ' final im pressions were m ade had a new design fork with rein fo rced sliders, slightly less stro ke an d better feel , m ain ly as a result o f elimin ating th e binding som etim es ' en countered with the eigh t-inc h ers. It also h ad Marzocchi number two gas-flui d dampers at th e rear which may well be th e fines t sho ck to ever be offered on a stock m otocrosser . By the time y o u bu y yo ur KTM , there may be an improved versio n of th e fro nt for k on it but don 't hold y our breath . Th e cu rre n t Ceriani is a noticeabl e improvement at 7.5 in ches of travel. Gary 's fo rmer bike also h ad th e snorkel frame to the airbo x as was then standard on all 25 0s imported into the U.S. We always felt , intuitively sinc e our calib ra ted flowmeter was always in ne ed o f n ew parts, th at th is arr angem en t restricted breathing at the hi gh RPM ne cessary for 250s to make significant [i.e ., winning) h orsepower; th at the engin e had much more potential, etc. The new KTM breathes directly through th e un ders eat airbox and it b reathes more as a result . "Ah aI" ca me the th ought, " th e n ew airbox is not ch o kin g off the engine at high revs an d th at is wh y it is fast er at the top of each gear than previously ." Well, life being a co mplica ted business that was only part ially true. .Th e porting on the 250 KTM has always been conservative - keeping the enduro-trial app licat ion in min d - but now that too is changed. Th e stock cylinder (on Gary 's bi ke) ha d mucho low RPM grunt and, if y ou co uld sh ift fast en ough , would co m e out of the hole ahead of anything onl y to get passed som ewhere ar o und the top of fourth gear if the starting straight was th at long. It often was. Grumble , grumble . Th e solution for the Oregon woods was not the sol u tion for a 100-me ter long Grand Prix st art straight. So Gary inserted a Carl Cranke-prepared cy lin der and p ipe into his last-model-but-one KTM . Carl developed the cylinder by getting the KTM factory m otocross cy lin der spe cifications and m assaging them into reli able p erformance as only Carl can. When that engine came on th e pipe , it turned a red and silver motorcycle into a ro cketship . It also required holes drilled in the airbox covers to let it breathe at those spe eds. The owner-racer felt it was a little pipey . The tester-writer felt that it still had adeq ua te if no t exc essive lo w end and that the Cranke . specs' resulting performance was a b o nu s in terms of powerband tr adeoffs. Th e KTM 25 0 m ay have be en th e o nly 250 in pro ducti on that previously needed less low end torque, to keep' from brea king the rear wh eel lo ose abrup tly at low RPM, and s tuff like th at .