Cycle News - Archive Issues - 1980's

HORSEPOWER FACTORY o eo 0') if a guy gets all these pieces in the mail (from another firm) and the forks grind in th e steering head , then what? Who's he gonna ask? . " If he calls such-and-such a place and asks them what ca m works with what ca rburet ion , are they gonna be able to tell him? Probably no t. "We've done a 101. of R&D and found ou t wha t works. " Starting with engine hop-up , McCassy didn' t want to use any sandcast , d iecas t or forged pistons , only factory pis tons. The reason for this is he feels tha t the factory OEM pistons have more silicone and are more compatible with the cylinders, expanding at the same rate as the engines heat up . For insta nce , after a lot of looking and che cking , he found that a Honda CL350 pis ton would fit the XR185 cylind er after a 1mm overbore that brought th e d isplacement to 190cc. The piston d id have to be modified for; different clearances and oth er HPF re quirements , so d on 't just drop on e into you r 185 cylinder. McCassy a lso developed a special aluminum intake manifold for the 32mm Mikuni to get just the rightJ:) powerband he was after on the 185 .!J He tried 37 different pipes beforejsettling on the one he felt was best ' la The stock cams are reground using the ":! same duration and lift but the lobes are relocated to HPF specs. • About the only things used that will .f be available from other distributors are S&W valve springs and Super Trapp silencers, though the 500 uses the stock head pipes wh ich produced the most power. Much of the engine development work was done on a dyno where McCassy reponed a sizeable increase over stock horsepower from the 185 , double stock horsepower from the KLX and 45 rear wheel horsepower on the XR500 (10 more than stock across the board and more than the Honda performance kit) . When it came to getting the bikes to handle, McCassy turned to C&J for h~ Replica Racer frames and Moto-X . Fox and Ohlins for suspension. He had C&J build the frames to his specs and will use (and sell) Fox Factory Forx and Shox, though Ohlins will be avail able for the rear if the customer desires , Horsepower Factory Replica Racers available include the 500 hop) and 185 (above). They're light, goo d handling, have ample power and co st a bundle. They were also designed t o last a long time. By Mark Kariya In the early era' of dirt biking, real motorcycles were generally big British twins or singles. And, they were four-strokes (in case you d on't remember). H owever, Greeves and H usky (twostrokes) made their debut, in extreme1y tiny quantities at first and the pendulum began to • ••• • swmg with mcreasmg speed until 16 the only bik e to have in the dirt was a two -stroke . T he pendulum now appears to be swinging back due to tightening EPA regulations. All four of the big Japanese companies now have good dirt-going thumpers. It is even rumored th a t Husky is developing a four-stro ke. The many thousands who hav e grown up on two -strokes. though, believe there is no such thing as a light , fast , good -handling four-stroke din bike. Nonsense. -_ .. - ~ ~ - -- _ - . Fou r ~trokes can get arou nd in th e dirt quue well . Granted , there are !I'any modifications that must be done In order to get a thum pe r pared down and going quickl y. And many of these mods requir e hand -fabricating items or losing th e four-stroke's repu ta tion for reliability. Enter th e Horsepower Factory. Located in En cinitas. CA , ju st up th e coast from San Diego . HPF opened their doors recently with Malcolm McCassy and Tom Siegel a t the helm . Their goa l? To produce and sell items for the Honda XRs (from th e 185 up) and Kawasaki's KLX that would make th em fast, good -handling and reliable . Replica racers ut ilizin g th e whol e bag of tricks would also be available. .. --. _ _- -- - - They are no strangers to the pe rform ance ga me. McCassy was associated for severa l years with the Flying Machine Factory wh ich Honda went to for engi ne work on th eir factory motocrossers. H e has dabbled in both ca rs and bik es since high schoo l and seems to run 100 m iles an hour himself, perha ps a characteristic of his work that has rubbed off on him . " I wanted to do on e of th ese (fast thumpers) wh en the first four strokes came ou t. 1 wanted to build something that was quick and dependable. My whol e concept is to go 10 .. . 20 ,000 miles ." His philosophy was " . .. something along the lin e that big isn 't better. You don't need to go to 6 ,OOOcc." He also wanted all the pieces he sold to fit properly, something he feels is overl ook ed in many ca ses. "W e want to be able to sell it (t he HPF product lin e) to the kid in Kansas wh o doesn't want to fool a rou nd with th ings that don 't fit :' For example, "We've been doing fo;k swaps for years so it's no sweat but The frames utilize th e engi ne as a stressed member which both lowers th e. center of gravity and reduces unnecessary weight. There is 12" of travel front and rear with a banana swinga rm keeping the seat height surprisingly low. H e stayed awa y from aluminum swingarms because of som e bad experiences with them . '1 Sun rims , eight -gauge Buchanan spokes and CR250 hubs ( the 185 uses a stock XR rear hub) provide strong bases for th e Metz eler tires. On th e 500, '79 CR250 ta nks. seats and fenders a re used. McCassy estimated the weight of his Replica Racers to be about 210 Ibs. for th e 185 and approximately 240 for th e 500 . The KLX looked almost stock. McCassy admitted that it m ight be the best way to go for a guy who doesn't want to sink too much into a thumper playbike. He set his up with 1980 KX250 forks and piggyback Ohlins. Engine work includes a 34mm Mikuni on a HPF manifold , an HPF cam , 11.3 :1 compression ratio due in part to a reworked Honda CB500T piston and a larger head pipe. Dyno tests showed the stock silencer produced the most horsepower so it is retained . As the old saying goes , however, the proof of the pudding is in the eating and wh en McCassy offered eN the chance to rid e th e bikes at Carlsbad for a few hours , we jumped at it. Since an XR250 Replica Racer hadn't been .. -= ~ & :. •

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