Cycle News - Archive Issues - 1980's

The SC Racing modifications g}ves the 1986 Suzuki RM250 instant throttle response and trench-digging horsepower - the way it should be. SC Racing Suzuki RM250G I!.0P-UR Making the RM w rk like it should By Kit Palmer It's no secret the 1986 Suzuki RM250G needs a lot of work before it's truly competitive. In stock form, the Suzuki's motor is a slow revver and lacks low-end pull, and the suspension is too mushy up front and way too harsh in the rear. . D eSl?lte a II'h at,. we fe It t h e t SUZUkI has potenual as a top 250<:c motocrosser, able to compete heads up against the Honda CR250. But it would take some major tuning. We handed our Suzuki to Mike Norris, founder of Suzuki Country Rae-in Norco, California, who has worked with Suzuki suspensions and motors for nearly 10 years. Finding more power and quicker throttle response out of the motor requires the crank to be removed and lightened, according to Norris, who says the stock crank is way '00 heavy. The lighter crank allows the engine to pick up revs quicker, but Norris doesn't lighten it to the point where bottom-end grunt would be lost. Healsohasa couple other tricks he applies to the crank, then he modifies the crank cases. Norris files and re- shapes the crank cases to allow beller gasnow.angle~romtheboo~terporLs. The cylmder IS ported wllh much attention to the intake and booster porL shapes. Norris says he has basically two ways of porting the cylinder: one for the Beginner through InLermediate class level riders, while the other is built strictly for Pro riders. Our Suzuki was given the Beginner through Intermediate treatment. He also mills the head· to increase compression. Other modifications include boring and reshaping the carb, installing a Bill's Pipe and extending the clutch actuating arm for a lighter pull. Suspension-wise, Norris installed an ATK fork kit and revalved the damper rods by increasing com pression and decreasing rebound. Along with a few other minor modifications, such as a diHerent fork oil level, weight and damping adjust- ments, the fork i set. In the rear, the Kayaba shock also gets the revalving treatment and a change of oil. Norris modifies the shock body by adding a hard-anodized coating, which increases the oil's life span. We left the stock spring on our Suzuki, but SC Racing has stiffer or softer spring rates, according to the rider's weight. Norris also installed a handlebar brace he built that mounts to the handlebar clamps, which is designed to eliminate handlebar £lex, thus improving from-end tability. TheSC Racing modifications made a huge difference in the way our Suzuki performed on the track and all the changes were for the better, especially the motor. Throttle responce when exiting turns i now awesome. Gone is that slow-revving, fan-the-clutch syndrome it once had exchanged for a more powerful, quicker-hitting motor. It's still helps to tap the clutch for quick getaways out of the turns, but it's not a neccessity like it used to be. Our SC Racing Suzuki hits extremely, yet, predictably hard out of the turns and continues to pull hard through the gears. No matter how low in the rpm range, one quick fan of the clutch brings the Suzuki up to trench-digging speeds. Even without the clutch, the SC Racing Suzuki can Le chugged through the turns with enough low-end left over to speed out of the hole smoothly and quickly. After the modifications are done to the suspension, the Suzuki works like a charm. Gelling the forks working correctly made the biggest difference in overall uspension performance, and combined with the plusher and smoother rear shock, the Suzuki glides over the gnarliestof bumps. The back end isn't perfect, though, it still is a lillIe' harsh over the smaller, sharpedged bumps, but the SC Racing modifications are 11 definite improvement over stock. Our SC Racing-modified Suzuki RM250F is a 100% improvement over the stocker, and combined with the Suzuki's already proven qualities, such as cornering, it's ready to take on the competition. orris says he's also had extremely good luck modifying the underpowered RM125, but the cost is slightly more, since the work to the 125 is more extensive than the 250. The SC Racing RM250 is definitely ourchoi e over any stock Japanese 250cc motocrosser on the market when it comes to hard-core MX racing, and if you don't have the bucks for a new bike next year, we feel the SC Racing touch can make the RM250G competitive for at least another season - easily. Prices: Crank work , $85.00 Cases , $20.00 Cylinder $95.00 Head , $20.00 Carb $55.00 Pipe $139.95 Shock mods $149.00 Fork mods (w/springs) .. Approx. $100.00 Handlebar brace ..... _... $19.95 For more information, contact Mike Norris, Suzuki Country Racing, 2057 . Hamner Ave, Norco, Ca. 91760. 714/734-0640. •

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