Way back, Honda, Yamaha and the opposite Japanese producers skilled us to consider that no street-legal bike could possibly 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 supplied bikes that wanted solely slight modifications to be dirt-worthy. Within the face of ever-tightening laws, 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 by 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 absolutely street-legal this yr. As such, sellers, aftermarket corporations, 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 one-overhead-cam motor is loosely primarily based 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 circumstances are totally 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 gained’t be sufficient juice to energy the EFI system and it gained’t begin anyway.
So as to make a street-legal bike out of a motocrosser, KTM engineers needed to work laborious. 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 go. Simply having a quiet muffler isn’t sufficient. The consumption, chain and tires are contributing components. All the things 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 could possibly 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 authorised, however have carefully spaced knobs that produce much less rolling noise.
All the things in regards to the EFI system is new for 2017, together with the Keihin throttle physique and EPA-approved gas mapping. In contrast to the motocross bike, the system is claimed to be fastened; 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 threat huge penalties, notably in California. There are corporations 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 gas tank is larger than the motocross bike’s, however not that a lot greater at 2.25 gallons. For that matter, the bike isn’t a lot heavier than the MX bike at 244 kilos with out gas and with mirrors.
For the reason that bike is meant to be tamper-proof, right here’s the massive 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. General energy and energy supply are each wonderful. The EXC may be very responsive on the backside of the powerband simply above idle. Within the center, it pulls as laborious as any off-road bike bought, and solely on high does it taper off early—at the very least, early in comparison with its closed-course brethren. It does all this with an exhaust word that’s quieter than that of the Yamaha TT-R125. The bike is so quiet that you just hear plenty of different noises that you just wouldn’t in any other case discover. There’s slightly chain slap and an odd buzzing coming from below 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’d even be slightly 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 gas mapping goes, KTM engineers did an incredible job, nevertheless it’s clear that the EXC is lean. It needs to be to be able to get EPA’s blessing. From time to time the motor will hiccup, and for those who’re going sluggish, it’d even stall. General, it’s not an enormous challenge, however in chilly temperatures, it may be worse. On sizzling days, alternatively, 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 time, however we all know that the competitors bikes that use this motor can boil for those who abuse the clutch or trip for prolonged durations at very low pace. This bike does have a six-speed gearbox, and gearing is just about spot-on for off-road using, so there’s no purpose to tax the clutch below regular circumstances.
We have been slightly shocked that KTM didn’t use super-tall gearing to assist with the varied certification assessments. If you get the 500EXC out on the open highway, it feels slightly 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 seems 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 burden. That 244-pound determine is for actual, and also you don’t even want the stunningly correct Filth Bike super-scale to show it. You understand the KTM is as gentle as any four-stroke off-road bike from the primary trip. It’s only some 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 type of traits which have come to outline dual-sport bikes and made us yearn to change them. Now, KTM has finished such a tremendous job of trimming off kilos that there’s no method that you would do higher. Nearly any aftermarket half you placed on the bike can 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. When you have been to trip solely filth on this bike, the stuff you would possibly wish to change, and legally can change, are the tires and the suspension. The WP Xplor fork and shock are comfortable and comfortable to an excessive diploma. That makes for a cushty trip whenever you’re on the bike for hours overlaying miles, however the suspension is simply too comfortable for something however an off-the-cuff tempo. Inside the brand new fork and shock, many of the components are smaller and lighter than these on WP’s earlier open-chamber off-road fork, which implies it’s going to take quite a lot of clicks right here and there to cope with laborious off-road using. You may need to go to stiffer springs and perhaps even an skilled suspension tuner. So far as the tires go, we have been shocked at how little grip they supplied in mud and sand. Continental TKC80s have at all times been our favorites for journey bikes, however on a motorbike nearly 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 have been delighted.
TURN KEY, RIDE DIRT
Ultimately, suspension and tires are the one issues you need to alter on the EXC. Then the bike is 100 p.c prepared for a nationwide Enduro. You would possibly break a blinker or crack a mirror, and that hanging half below 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 alter—the best way we consider dual-sport bikes.