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/126334
1""""4 1""""4 M 1IJ ..c o ... u o Laurens uses DID rims on Marty's bike for their added strength, and claims the stock RM spokes to be up to the task of holding the wheels together under the pounding of National competition. As far as tires, Marty likes a Metzeler up front and a Dunlop at the rear, though his choice is certainly based on the contingencies available from both brands at National races . I 'A fairly expensive trick includes the use of as many titanium bolts and fi!ting as possible to add strength and reduce weight. So, despite the longer suspension. bike weight remains low at 192 lb . dry and 198 lb . ready to race. The LOP swingarrn .keeps the bike's wheelbase at the stock 55-inch length. One easy modification you can make if you needed it is install foot pegs from an older model RM onto your C. model. The part number is 41102 and this peg is stronger and taller than the present pegs . Now for the part you've all been wa iting for, engine modifications. Naturally, LOP markets a complete engine kit similar to the one on Marty's bike . Included are a radial head, prejetted 36mm Mikuni, porting work on your cylinder, phenolic reed petals. MOIO-Tek ignition which allows higher rpm and an LOP 11 Stage airfilter. The modifications work. Riding Marty's bike proved it to be a rocketship, as fast as a works RA Suzuki, if not faster . The rpm range of the engine is raised considerably, but at a sacrifice of nearly no power below 6,000 rpm . Proper shifting becomes very important to keep the powerband working. Clutch work is also important because even on upshifts the next higher gear sometimes felt it wasn 't close enough to engage the powerband again. What it all comes down to is the fact this is an "Expertonly" engine kit. Not only do you need the skill to use it . but you need a fast wide-open track to let it run. On slow or rough courses you're better off with the stock engine. This was pointed out by Laurens in the fact that LOP offers no trick exhaust pipe for the RM. "The stock pipe is tuned best to work with the rear transfer ports in the cylinder. No other pipe design will work as well throughout the rpm ral}ge. Suzuki did a lot of work to get this pipe right , and we can't improve upon it .· By changing the transfers we can construct an exhaust system that works better at low rpm or at high rpm, but not as well throughout the rev range as the stock Suzuki pipe," he stated. For most riders, I'd think the major modification to the engine would include a larger 34 or 36mm Mikuni (proven to increase mid-range torque and smooth out the powerband) and the MOIO-Tek ignition (extends the top-end range of the powerband and allows the engine to run cooler). Modification beyond these will have you wearing yourself out trying to ride the bike, as well as changing pistons, rings, and other parts faster than the stock Suzuki engine already has you doing. Wrapping things up, Marty's LOP modified Suzuki is a fantastic bike. Handling is exceptional - presently at the limit of the art . Power is just as fantastic and highly competitive for National Championship racing, but at a sacrifice to tractability and reliability. Unless you have the skill of Marty Moates and need the advantage, stick to engine modifications that make your stocker only a ' little faster with increased tractability. For complete information on all LOP products their 1978~ catalog is available for $2 . Suspension parts not available from LOP are available from Moto·X Fox . (Opp. pege) Laurena Offner. (Above) Rear end feetUrea bent awlng8rm and Fox Airahox. (Below) engine la reworked but retaina stock pipe. LOP 2010 Washington Street Waukegan, IL 60085 !12/!!6-00!2 • 19