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/126850
..- The countershaft-mounted, rear disc brake assembly centralizes overall weight and is le s s prone to damage; however, drive chain stress doubles. I found th e rear di sc brake to be very stro ng. stro nger th an th e rear br ak e on a ny ot her bike I'v e ridde n. It wa s really hard not to let th e back tire lock up. which is kind of scary at first. but I go t used to it a nd sta rted using th e slid ing to adv antage in th e tu rns . ( Leimer was defi ni tely rig h t a bo u t one -th in g - no ma tter how fast I ca me into a turn a nd ho w h ard I used th e rea r brak e. I co u ld not get th e back en d to cha tte r a t a ll. I wa s very much impressed . Tha t stro ng. cha tterl ess rear brake co m bined with th e powerfu l front disc to make th e ATK easy to bring down to a sa ne spee d through the turns after a long stra igh t. On th e d ir t, th e ATK was a bla st to slide arou nd; sliding was easy to do with th e kn obby-less tires. but hooking up out o f the turns was nearl y (Above) 30 m inutes la t e r, we changed Eklund 's Superb iker ATK back int o an MXer. (Be lo w) T he front disc brake and Rotax motor a re s uper strong . 1986 A TK Eng ine ty pe Air-cooled, SO HC single Bore x stroke 94x8 1mm Displacement 562cc Compression ratio .' 9 .8 :1 Carburetion Mikuni 38mm Horsepower 51 bhp @ 9500 rpm Torque 40 lb.-ft . @ 6000 rpm Valves per cylinder . . . . . . . . . . 4 36mm Intake valve size Exhaust va lve size 32mm Intake lift 10.5mm Exhaust lift 10.5mm Included va lve angle 62° 40°-70° Intake valve tim ing Exhaust valve timing .. 72°-30° (measu ring pt .) Omm Starting system Primary kick Ignition COl Lubrication Dry sump Primary drive .. 76 /32; 2 .375:1 Final drive ... . 15/4B; 3.200:1 Gear ratios 5th 21/23; 0 .913:1 4th 19/17: 1.118:1 3rd 2 1 / 15; 1.400:1 2nd " 23/13; 1. 7 6 9 :1 31 /13; 2 .384 :1 1st Rake 27° Trail 4 .4 5 in. Front s uspension type Inverted White Power 40m m Fork tube diameter 11.8 in. Front w heel tr ave l Rear suspens ion type . . . Singleshock swingarm 12 .0 in. Rear wheel travel Front bra kes 8.0-in. disc Rea r brakes 6.5-in. disc Front wheel : . 2 1 in. . Rear wheel. 18 in. Front tire 3.00- 2 1 Metzeler Rear tire 5 .10-18 Metzeler 249 1M. Claimed dry weight Overall lengt h 84.0 in. 32.0 in. . Overall width Overall he ight 54.5 in. Wheelbase 58.0 in. Fue l capacity 3 .3 gal. 13.5 in. Ground clearance Seat he ight 37.5 in. Colors . . . . . . . . . . . . . . . .. White Retail price $4590 impossible. Dirt -tra ckin g it th rough th e turns was very contro llable. a nd it was o n dirt-tra ck th a t I foun d th e wi de handlebars to be th e h ot set up. After spe nd ing a few hours on th e bike in Superbikers tri m . I ha nded it over to Leitner and said. " ma ke it a mot ocro sser!" Less th an 30 minutes la ter, it was ready In th is short period of tim e. Leitner a n d hi s crew ins ta lled n ew handlebars with a narrower bend. 18- and 21-inc h wheels with knobby tires. a longer shock and fork s. a nd a different fro nt fender. . I didn 't have a ny problem s adaptmg to the jumps. whoops a nd berms on th e MX version ATK. Actu all y. I wa s very im p ressed by th e way it performed . Suspension was plush a n d predictable, th e motor got me from turn to turn as quick a s a ny twostro ke cou ld an d turning was precise. T he ATK is heavy, however . a nd co m bi ned with its ra w horsepower. th e bi g th um per wore m e o ut in a hurry. T he rear bra ke was way too strong o n the motocross track . It took delica te foot co ntro l o n th e pe da l to keep the AT K from sta lli ng. w h ich I d id a number o f times. Lu ckil y the ATK sta rts ver y eas ily for a big -bore thum per. The ATK's a bility to tra ns form from a co m petit ive S u per b ikers mount to a co m pe titive motocrosser wi th su ch little effo rt . cos t and time is reall y impressive. U n fo rt u na tel y. there is no mas s market for Super bikers-typ e m otorcycles - yet. But if th ere wa s. th e ATK would have a handle o n it. I'm su re. In stoc k form. th e ATK wei ghs 249 pou nds dry and sell s for $4590 . More in forma tio n is ava ila ble fro m Le itner a t 2650-C Walnut Ave.. T us tin . CA 92680. il4 /73 1-5114.- - - _. - .. - - • 7