Here’s what you can do to make the 2017 KTM 300 XC even better. And, yes, believe it or not, it can be made better.
It’s 2017 and the year is only half over and we’ve already had a taste of the revolutionary 2018 KTM 250 TPI fuel-injected two-stroke and like everyone else, we can’t wait for them to land on U.S. soil. But for those who want a traditional carbureted two-stroke, and not ready to make the transition from carb to FI, KTM is still selling the 250 and 300 in its carbureted form for 2018.
Notorious bike builder Jay Clark didn’t want to wait for a fuel-injection model, so he set out to build the best KTM two-stroke trail bike possible, starting off by using a 2017 KTM 300 XC.
Click here to read this in the Cycle News Digital Edition Magazine.
Story and Photography by Adam Booth
A Mix Of Goodness
While this might be a 2017 KTM 300 XC, it looks like a 300 XC-W thanks to the headlight from an XC-W. It bolts up easily and the plugs are already on the XC and waiting for a light. Completing the XC-W look is the rear fender and brake light off a KTM XC-W. Again, it bolts up easily with the wiring and plugs readily available on the XC wiring harness. The reason Jay didn’t just buy a 300 XC-W is simple: he likes the transmission from the XC more than the wider ratio XC-W. He also prefers to have linkage rather than PDS and wanted the WP AER fork over the Xplor fork.
While the stock XC suspension works decent for trail riding, for this particular project Race-Tech re-valved both ends to still absorb small hits while eating up bigger bumps at aggressive trail riding speeds.
To help protect the shock linkage from trail damage, a Pro Moto billet guard replaces the stock protective link. The Pro Moto billet guard is also adjustable for those looking for different handling traits. On this bike, it was used in the stock position.
A lot of KTM lovers weren’t exactly happy on KTM’s decision to ditch the Keihin carb for the Mikuni, and we weren’t either. The Mikuni is much more finicky to set up and more sensitive to altitude change. The main focus of this project was to improve the performance of the carb.
Clark completely changes the jetting and also performs a slide modification, which helps to rid a rich spot at about ¼ throttle that is really hard to eliminate. A triangle file is used to cut a notch in the slide. On top of the slide modification, the jetting is as follows: 420 main, 35 pilot, 43-75 needle in position two. The air screw is 1.5-2.5 turns out.
A V-Force reedcage replaces the stock reeds. To up the compression, .018-.020 was cut off the head, providing a bit more bottom to mid power without hurting the top end. This amount keeps the engine safe for pump gas.
Other cool additions to the 2017 300XC/XC-W include a fresh coat of orange powdercoating, an FMF pipe and Powercore non-sparky muffler. For riding in areas that require a sparky, Clark swaps the muffler for an FMF Q.
Protection for the pipe comes a P3 carbon guard. Full Cycra orange plastic, covered in Decal Works graphics and a MotoSeat cover completes the cool look of this KTM two-stroke.
Two-Stroke Trail Bliss
The 2017 KTM two-stroke engines now have a counterbalancer, taking the typical vibration associated with two-strokes and turning it into a faint memory. The trade off to a new engine without vibration is change from a proven Keihin carburetor to a more finicky Mikuni. A large chunk of our curiosity to ride Clark’s KTM was to see if his claims of better jetting from the Mikuni carburetor were true. We took his unscathed and beautiful bike straight to the technical trails, knowing the rear trials tire would provide excellent traction while testing the jetting and the suspension.
Response throughout the rpm range was crisp and predictable. We spent a lot of time lugging and crawling up rocky canyons, many that were used during the Last Dog Standing race at Glen Helen Raceway and the jetting was consistent without any rich areas in the rpm range. With a properly jetted engine and a sticky trials tire, there isn’t a lot that can stop a 300 two-stroke when the terrain is technical and nasty.
Clarks’s carb set up was noticeably better than stock, making the 300 even easier to ride. The Trail-Tech fan kit and IMS overflow catch-can provided overheating protection, even in the 90-degree heat we rode in at slow speeds. The slight engine and carb mods didn’t hurt the midrange or the top, letting us ride aggressively in the more-open trails and even roost around the motocross track a bit.
Crawling up and over rocky trails abuses the clutch on any bike, Clark chose to install a Hinson inner hub and pressure plate kit, which includes fibers, steel springs and outer cover kit. Pull at the lever was smooth and we didn’t experience any fade or have any issues on this day.
Suspension is a very personal preference and Clark’s set up does a good job of providing decent comfort at slow speeds while holding up nicely at higher speeds. The trials tire does a great job of soaking up little trail hack, but it also gives the bike more of a springy feel due to the tall and soft sidewall. If ultra rough trail at slow speeds was the only riding this bike was going to see then we’d go softer on the suspension, but Clark’s set up allows a good balance for all types of riding and doesn’t pigeon hole it into strictly a trail bike.
Typical of a Jay Clark bike build, there is a lot of cool stuff adorning this machine, some parts critical and some just downright bitchin for the sake of being bitchin, like the razor sharp Scar footpegs.
Because true trail rides often turn into very long hours away from civilization, the IMS 3.5-gallon tank is a necessity and provides over 80 miles worth of fun. Bashing through the bush is the norm on a trail ride and the Cycra wrap-around Ultra Pro-Bend handguards did a good job protecting our fingers and the levers when we dropped Clark’s pretty bike.
A Motion Pro Titan throttle tube with the end cut to allows the handguard to mount to the handlebars. We had a good time putting a few scratches and shaving off the front edge of the tacky trials tire on this looker of a 2017 KTM 300XC/XC-W.
For riders who don’t want a wide-ratio transmission and prefer linkage in the suspension, here is what you can turn your XC into! CN
SHOPPING LIST
Pro Replica Piston kit
Head machining
V-Force reed cage
Gnarly Pipe/Powercore 2 Silencer & Sparky Legal Turbine Core 2
Pipe carbon guard
Rear Stealth sprocket 51T (one larger than stock)
Overflow bottle in the frame & oversized fuel tank
Ultra Pro-Bend Full Wrap Around handguards, Full Plastic kit & Full Armor Skid Plate
Two-stage air filter
High-pressure radiator cap
604 Fat Bars & Tacky grips
AT81 front 90/90-21 & D803GP trials rear 120-100-18
Custom Cool seat cover
Bike stand, brake caps & fork air filler (EZ Fill)
Fibers, steels, springs and outer cover kit & full inner hub pressure plate kit
Oversized rotor, adaptor bracket, rear disc, complete wheel set, brake bolt kit, sprocket bolts kit, lightweight lithium battery, rear brake rotor guard, O-ring chain
4.6 rear spring (one stiffer than stock), fresh fluids and seals & Re-valve setup
Linkage/guard and lowering optional
Titanium footpegs
Radiator fan
Rear swingarm guard & radiator braces
Semi-custom graphics kit & pre-printed number plates backgrounds
R-50 two-stroke premix
Grip glue & titan throttle tube
Slide-and-guide kit
Frame guards
Sandblasting, powder coating and “race prep masking”
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