Way back, Honda, Yamaha and the opposite Japanese producers skilled us to consider that no street-legal bike might be a reliable filth bike. DOT tools made them fragile, emission tools made them run poorly and security tools made them heavy. Husky, KTM and Beta modified the sport. Since 2007, the European makers have provided bikes that wanted solely slight modifications to be dirt-worthy. Within the face of ever-tightening rules, although, the job is harder than ever. Even off-road bikes are confronted with tough emission and noise restrictions. That’s why KTM dropped its path bikes in 2017. If the corporate was going via all of the expense and energy to make a motorbike clear and quiet, it made sense to go a step additional and make it street-legal. All of KTM’s present choices that aren’t closed-course, competitors bikes are totally street-legal this yr. As such, sellers, aftermarket firms, journalists and even non-public events aren’t allowed to change the emission or noise tools.
So the brand-new 2017 KTM 500EXC has excessive expectations. It has to hold the torch for each the dual-sport bike it supersedes, in addition to the now-discontinued 500XC-W path bike. The only-overhead-cam motor is loosely based mostly on the one within the 450 motocross bike that was new in 2016. It has a six-speed transmission as an alternative of a five-speed, the stroke is eight.6mm longer for a displacement of 510cc and the instances are completely different to accommodate a kickstarter. There isn’t a kick-start lever there in inventory type, however KTM theorizes that dual-sport guys usually tend to distrust the electrical starter and wish to set up a guide starter as a again up. It must be famous that if the lithium battery is totally useless, there received’t be sufficient juice to energy the EFI system and it received’t begin anyway.
With the intention to make a street-legal bike out of a motocrosser, KTM engineers needed to work onerous. Along with emissions restrictions, the EPA has a drive-by noise take a look at that’s very tough for an off-road bike to cross. Simply having a quiet muffler isn’t sufficient. The consumption, chain and tires are contributing elements. Every part KTM did to make the bike quiet and clear is legit; there are not any “pretend” measures like a throttle cease or a peashooter within the muffler. After testing and extra testing, engineers borrowed expertise from the automotive world and put in a reed valve between the air filter and the throttle physique. The design, which KTM calls “velocity-focused consumption,” killed simply sufficient consumption noise in order that the airbox might be extra open. The corporate’s in-house take a look at riders additionally say that the reed really elevated low-end torque. The bike makes use of Continental TKC80 tires, which aren’t solely DOT authorized, however have intently spaced knobs that produce much less rolling noise.
Every part in regards to the EFI system is new for 2017, together with the Keihin throttle physique and EPA-approved gasoline mapping. Not like the motocross bike, the system is alleged to be mounted; you possibly can’t change to a richer or leaner map with a laptop computer. We hear that jail-breaking the system is feasible, however retailers who do that danger massive penalties, significantly in California. There are firms that make piggyback EFI tuners that change the mapping by hijacking and altering the sign between the bike’s central processing unit and the injectors. These, in fact, are thought of for competitors use solely.
KTM has redesigned the EXC chassis for 2017 with a brand new model of the no-link PDS rear suspension. Off-road guys nonetheless want this setup over the linkage-style design used on the competitors bikes, primarily due to higher floor clearance. Within the entrance, a WP Xplor fork is used with good old style metal coil springs. The gasoline tank is larger than the motocross bike’s, however not that a lot larger at 2.25 gallons. For that matter, the bike isn’t a lot heavier than the MX bike at 244 kilos with out gasoline and with mirrors.
Because the bike is meant to be tamper-proof, right here’s the large query: is it adequate in inventory type? Sure! It’s really a greater filth bike than the all-dirt 500XC-W that KTM left behind. Total energy and energy supply are each glorious. The EXC may be very responsive on the backside of the powerband simply above idle. Within the center, it pulls as onerous as any off-road bike offered, and solely on prime does it taper off early—no less than, early in comparison with its closed-course brethren. It does all this with an exhaust observe that’s quieter than that of the Yamaha TT-R125. The bike is so quiet that you just hear a lot of different noises that you just wouldn’t in any other case discover. There’s just a little chain slap and an odd buzzing coming from beneath the seat. That’s the reed valve. KTM’s declare that this design will increase low-rpm output might be correct. The EXC makes energy from the primary crack of the throttle. It would even be just a little an excessive amount of, too quickly. The one single-cylinder bikes that can out-torque a 500EXC are full-blooded avenue racers—the KTM 690 and Husky 701.
So far as gasoline mapping goes, KTM engineers did an incredible job, but it surely’s clear that the EXC is lean. It must be so as to get EPA’s blessing. Infrequently the motor will hiccup, and when you’re going sluggish, it would even stall. Total, it’s not an enormous concern, however in chilly temperatures, it may be worse. On scorching days, then again, the bike runs heat. That’s one other trait typical of fresh emissions and a quiet exhaust. That is successfully dealt with by a radiator fan. We haven’t but ridden the bike within the full grip of summer season, however we all know that the competitors bikes that use this motor can boil when you abuse the clutch or journey for prolonged intervals at very low pace. This bike does have a six-speed gearbox, and gearing is just about spot-on for off-road driving, so there’s no motive to tax the clutch beneath regular circumstances.
We had been just a little stunned that KTM didn’t use super-tall gearing to assist with the assorted certification exams. Whenever you get the 500EXC out on the open street, it feels just a little misplaced. Most dual-sport bikes are geared in order that 65 mph has the motor loping alongside at low rpm. Not within the EXC’s case. The KTM EXC motor spins pretty quick, the pegs vibrate and the wheels hop. There’s just one rim lock in every wheel, which throws them out of stability at excessive pace. In different phrases, the EXC appears like a dust bike.
WAIT, WHAT ABOUT WEIGHT?
What places the brand new KTM in a class above earlier dual-sport bikes and maybe most devoted off-road bikes isn’t the motor, the mapping or the muffler. It’s the load. That 244-pound determine is for actual, and also you don’t even want the stunningly correct Grime Bike super-scale to show it. You understand the KTM is as gentle as any four-stroke off-road bike from the primary journey. It’s just a few kilos heavier than a Yamaha YZ450F motocross bike regardless of having an electrical starter, a kickstand and all that street-legal stuff. Extra weight, because it seems, is one other a kind of traits which have come to outline dual-sport bikes and made us yearn to switch them. Now, KTM has finished such an incredible job of trimming off kilos that there’s no manner that you can do higher. Just about any aftermarket half you placed on the bike will probably be heavier than the stocker.
As a result of it weighs about what a full-time filth bike ought to weigh, the KTM handles precisely like a full-time filth bike. It jumps, slides and turns about prefer it ought to. If you happen to had been to journey solely filth on this bike, the belongings you may wish to change, and legally can change, are the tires and the suspension. The WP Xplor fork and shock are mushy and soft to an excessive diploma. That makes for a snug journey whenever you’re on the bike for hours protecting miles, however the suspension is simply too mushy for something however an informal tempo. Inside the brand new fork and shock, a lot of the elements are smaller and lighter than these on WP’s earlier open-chamber off-road fork, which implies it would take quite a lot of clicks right here and there to take care of onerous off-road driving. You may need to go to stiffer springs and possibly even an skilled suspension tuner. So far as the tires go, we had been stunned at how little grip they provided in mud and sand. Continental TKC80s have at all times been our favorites for journey bikes, however on a motorbike pretty much as good within the filth because the 500EXC, they’re completely misplaced. We used a set of street-legal Dunlop D606 knobbies for many of our testing and had been delighted.
TURN KEY, RIDE DIRT
In the long run, suspension and tires are the one issues it is best to alter on the EXC. Then the bike is 100 p.c prepared for a nationwide Enduro. You may break a blinker or crack a mirror, and that hanging half beneath the license plate will doubtlessly get sucked into the tire, however the bike’s efficiency is as much as the duty. Different modifications will solely throw the bike out of stability and mess issues up.
Nicely, there may be one different factor that’s vital to vary—the best way we consider dual-sport bikes.