Cycle News - Archive Issues - 2000's

~RKSHOP) ~_....!!REPORT IMS/Yoshimura Off-Road Honda CRF450R orry, Honda, but we're simply not S , interested in racing your XR400R in a western off-road competition, Oh, we know, that bike is your "offi_ cial" midsized off-road thumper, and it's actually a respectable steed for trail-riding or tight, technical woods racing. But forgive us if we pass on that machine when the time comes to choose a weapon for hare £, hounds, WOReS races and the District 37 Big 6 GP Series, where your air-cooled XR four-honey's mellow power and soft suspension are simply out of their element. Yes, we're also aware Honda hasn't seen fit to make an offroader from its CRF motocross base, but IMS and Yoshimura did the job themselves. Now, if only someone would make an electric starter for the bike.•. The Result The CRF mill is already a decent off-road package (we know; we raced our stocker in the Glen Helen Six- and 12-hour races), so Yoshimura didn't need to go crazy with it. Basically, they gave it the same treatment that they do for Kyle Lewis' Moto XXX Honda motocrosser, blueprinting the tranny, clutch and crank and then performing some top-end porting and valve-grinding to boost bottom-end and increase top-end overrun (the already-healthy midrange is about the same). Yosh also bolted up one of its titanium Pro Series exhaust systems, only this one has a screen-type spark-arrestor end-cap and several choices of sound-deadening baffles. IMS supplied its new Fluidyne-made Pro Series radiators, largecapacity units that also are much burlier than stock (we've pretzeled a couple of radiators on our CRF test unit). The increased cooling capacity is ideal for off-road use. Utz Racing, Pro Action's East Coast outlet, handled the suspension duties. giving the shock a three-stage, incrementally adjustable, pressure-sensitive, self-adjusting valving system. We're not sure what all that means, but the result is supposed to be a reduction in midstroke harshness. The fork gets a unique three-stage valving system (two-stage is normal) that Pro Action says is ideal for off-road, since it is supposed to eliminate deflection off rocks and roots while still resisting bottoming. Ergonomicswise, the hot CRF mod this year is to switch to triple clamps with a different trail, a move that is supposed to aid cornering (by minimizing a tendency to wash out) and open up the rider compartment (Honda has altered the CRF's geometry for 2003). IMS went with BRP 22mm offset clamps (stock is 24mm), along with an Answer CR Hi-bend Pro Taper handlebar and cushy, dual-density Serias grips. To help stability, a GPR steering damper is utilized, and rather than run a tall seat (the stock unit is used with a Ceet grip cover), IMS bolted up its low-boy Pro Series footpegs (three different peg-locations are available). A 3.4-galIon IMS fuel tank increases range, and bomb-proof Excel wheels (equipped with pencilthick, straight-pull spokes and shod with Maxxis tires) are utilized. (The rear is an 18incher to reduce the possibility of pinch-flats.) Also bolted on were a few choice items such as an RK chain, a BRP chain guide, a full-coverage XRs Only skid plate, a Power Filter, a 48-tooth Renthal rear sprocket, and Cycra handguards. Acerbis blue-and-yellow plastic gives the biJke a cool, old-school Husqvama look. 46 JULY 10. 2002' ." U ." I • neVIl's A busy schedule of 2003 intros meant our time on the IMS/Yoshimura CRF was limited, though there's a chance we'll try the bike out at a WORCS race later in the season. Still, from the day that Kit Palmer and I spent riding the bike at San Bernardino, California's Glen Helen Raceway, I can tell you that this bike would be sweet in a high-speed, western off-road race. The motor is supersmooth, with a linear delivery; the increased low-end eases the transition into midrange. and I never found the top's limit. Suffice it to say that it pulls way longer than the stocker. The taller gearing also helps to smooth out the hit, spread out the gear ratios and make for a usable first gear, though I'd like to try a flywheel weight in technical conditions to avoid stalling. As for the suspension, it's plush enough that on braking-bump sections at the ends of sandy straights, the rear end stays planted and doesn't deflect to the side or hop up and down, meaning I had enough control in these situations to accurately guide the biJke into the narrow ruts of the subsequent tums. At the same time, the suspenders are stiff enough to absorb high-speed compression hits like when I flat-landed a couple of jumps. Kit noticed a tendency of the rear end to stink-bug, but that's probably due to the fact that he's so skinny and light that he could use a spring from a ball-point pen for a shock spring. Not exactly a sumo wrestler myself (though a bit heavier than Kit). I didn't have a problem. The steering damper makes the ride noticeably more stable, and I wish we had it on our own head-shaking CRF in the Glen Helen endurance races. It does mean that a little more effort is required in corners, but it helped enough when I backed off the resistance that I could notice the cornering benefits of the BRP triple clamps. Despite my lanky physique, I've never been a huge proponent of tall seats, as they jack up the center of gravity and make the rider more prone to getting cleaned off the bike in brush- or tree-lined comers. By sticking with the stock seat height and running lower pegs, IMS is able to accommodate my lengthy getaway sticks while still maintaining the bike's ability to comer. The tank is wide enough that it actually makes the seat feel narrow. but what are you going to do? Off-road racing requires extra fuel, and anyway, Steve Hengeveld has said that he likes how the big tank serves as a block to prevent the rider from sliding too far forward in comers. Kit and I both had fun on IMS and Yoshimura's project CRF, and I hope to get the chance to ride it more down the road. No, Honda still doesn't make a serious midsized offroad thumper, but with the aftermarket ever at the ready, who needs them to?

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