KTM 500 EXC ultralight

The previous build of my KTM 500 EXC ticked many boxes for adventure enduro, but it seemed that there were more levels to discover in ultralight adventure enduro.

Why the KTM 500 EXC?

Weight

The energy a rider spends on a difficult trail is directly proportional to the weight of the bike. The weight of the bike similarly affects the probability of spills and the energy spent on recovering from them and continuing the journey. Picking up bikes is energy consuming.

Suspension

The 500 EXC has great suspension already in stock form. It needs very little modification to work well in adventure enduro. The PDS design is very simple and has a minimal amount of bearings down low in harms way. The bikes with linkage suspension have many more bearings prone to dirt and water, which results in more maintenance and more spare parts to carry.

Engine

The 500 EXC has a good engine, producing enough power for adventure enduro. It has plenty of bottom end grunt for cruising and explosive power higher up for when you need it for obstacles and whatever. What’s best is that the engine doesn’t seem to be prone to stalling even with lower revs.

Gearbox

The 500 has an enduro gearbox, so the first gear is nice and short. It makes life a lot easier with tricky starts on steep technical terrain. The sixth gear is tall enough to keep a nice marching pace on transits, even with an enduro final drive gearing.

The Build

Handlebar

I prefer to use aluminium rail hand guards, instead of the OEM ones that are mounted from a single point. It’s not only for hand protection, but the rail also does a great job of protecting the handlebar, levers and throttle tube from damage in falls. The handlebar vibrates a lot, so instead of using the supplied sheet metal screws, I prefer to drill the mounting rail and bolt the deflector right through.

Even then I use Nyloc nuts or thread locker to make sure they don’t roll open in the vibration. I just cut the original closed grips to fit the rails, but a better option is to get a pair of dual compound open grips from KTM. I always use grip donuts, to avoid blisters on the outside of the thumb joints.

Levers

On the previous build I went with Midwest Mountain Engineering’s Clever Levers to ease the strain of clutch pull on the finger joints on long expeditions. However, I decided to go back to OEM versions, due to the fact that they’re cheap and do not need any adjustment in case they need to be replaced.

Pedals

I have a pretty narrow skid plate, which doesn’t offer much protection to the pedals. To give them a better chance of surviving small tumbles, I went with Hammerhead Designs pedals with titanium tips. The shifter is mounted on the engine with a single bolt, so it’s a good idea to make sure it doesn’t loosen and rotate off. Hammerhead produces a handy lock wire bolt for the shifter pedal which works like a charm. The brake pedal has the tendency to scoop trail debris between itself and the clutch cover. At worst, the jammed debris could break off the pedal. A security wire from the pedal to the frame will significantly reduce the risk of that happening.

Foot pegs

I use Paragon titanium foot pegs by Hammerhead. They’re very light, enduro profile and stay sharp. For a lower and wider platform, a great option in steel is the lowered rally pegs from KIT690.

CLUTCH

Apparently the brake lever tip teeth have a tendency of puncturing the clutch cover in falls. The P3 carbon clutch cover protector will prevent this from happening and also protects the cover from boots scratching it. Further back, the clutch slave cylinder guard should keep the clutch in working order after a snapped chain whiplashes though the front sprocket.

THROTTLE CABLES

The throttle cables are somewhat exposed on the top of the handlebar, and the KTM metal protector will give them a better chance of surviving a beating. To make sure the cables stay where they’re supposed to while fitting the tank, a set of bungees will do the trick. I run a strip of inner tube on both sides of the frame, from the tank’s top mount to its side supports.

SKID PLATE

I went with the P3 Carbon skid plate. Not only is it light and strong, but it has to be the most beautiful skid plate I’ve ever seen.

EXHAUST

The factory slip on silencer worked fine, but I decided to go with the Akrapovic titanium factory silencer and the Akrapovic titanium header. The silencer is lighter than the OEM can, which will make a difference as it sits high on the bike. It also adds a little torque and power throughout the entire rev range.

To keep my riding pants from melting, I fitted an SXS carbon exhaust guard. It was pretty small, so I upgraded to a P3 Carbon pipe guard, which is much longer and also protects the header section in addition to the pants. In the other end of the pipe I have a Giant Loop Hot Springs heat shield to keep my luggage from melting on the silencer

RADIATOR

The 2016 KTM 500 EXC had a radiator fan already fitted from stock. If it hadn’t, I would definitely have installed one. I used to run the plastic OEM radiator shields, but ended up investing in Bullet Proof Designs radiator guards. They are not exactly ultralight, but I appreciate the protection and they have performed extremely well, despite several crashes.

ENGINE TEMPERATURE SENSOR

I run a Trailtech engine temperature gauge on the radiator with the EZ-Install fin sensor, and the reduction in temperature is dramatic when the fan kicks in. It’s really handy for keeping an eye on how the engine is doing in steep, technical and slow terrain. It continuously shows the current engine temperature and regularly flashes the highest reached temperature from the last few minutes. Notice the ultralight ghetto zip tie installation to the handler. It turns out I’ve been wathcing Roadkill Garage way too much.

FUEL TANK

The original build had a single 19 litre KTM Powerparts fuel tank. Although its very convenient for long stretches without needing to refuel, I find it rather detrimental to body positioning. Also, it has a tendency to slosh around when around half way, and handling the bike when getting stuck or falling is of course more energy consuming with a full 19 litre tank. This build features the 11,5 litre tank from KTM Powerparts, and I’ll make up for the extra range when necessary, with a Giant Loop Gas Bag. The bike is much more nimble with the smaller tank, and I like the look of the OEM panels, which also offer an extra layer of protection to the tank.

I didn’t bother with putting an extra fuel filter or replacing the standard micro filter with a Golan or equivalent. Instead, I’ll keep an eye on the in-tank filter and do frequent changes of the micro filter. Every time the quick release is opened, the O-ring should be lubed with silicone grease before closing. If it gets too dry, the female connector will potentially catch on the O-ring an tear it, resulting in a fuel leak. I protected the the fuel tank quick release with a section of MTB inner tube. It’s tied in at the bottom, to prevent crud flying up into it. I left a small hole for draining water though.

AIR FILTER

I’ve upgraded the standard air filter bracket stud to the factory version to avoid any malfunctions on the trail. I use the standard TwinAir pre-oiled air filters. They can be washed out with normal dish washing liquid and then re-oiled. However, I prefer to carry several filters instead of washing and oiling one or two on the trail. This is because the weight of the liquids alone will be more than three filters. The preoiled filters are light and can easily be carried compressed into small ziplock bags. I run a dust cover on top the air filter to give a little more life on expeditions.

The airbox and intake sit very low on the bike, which will be a problem in deep water crossings. The airbox actually has a drain hole in the bottom, which will let water enter through it freely. I have yet to solve this puzzle, but I suppose the answer will be somewhere between waterproofing the airbox and building a temporary snorkel for the intake.

FINAL DRIVE

I prefer to run the standard enduro 13:50 gearing with SuperSprox Stealth sprockets. I also experimented with 14:50, and while it tops out at 150 km/h fully open, I found the first gear too tall for technical stuff. The 13:50 is fantastic on first gear technical ground and will still roll nicely at highway speeds up to 110 km/h. I suppose for rides with long sections of tarmac, carrying a 13T and 14T front sprockets might seem appealing, but I find it a little counter-productive.

I’d rather not carry the extra weight for weeks if I only need it for one or two days. Also, with the standard chain, the 14:50 gearing will bring some rear tyres too close to the swing arm and start wearing out the mud flap. I run the chain with a quick link, and a TMD chain guide with replaceable bottom slide. I don’t run a chain oiler, but use whatever oil I happen to find to lube the chain.

SUSPENSION

I’ve upgraded to a stiffer 80 N/mm spring in the shock to compensate for the luggage. I’ve also added a quick preload adjuster collar, to avoid having to carry a shock wrench to adjust it. The forks are in original form.

WHEELS

In stock form, the 500 has the rear sprocket bolted directly onto the hub. It’s fine on dirt, but on tarmac it may have serious consequences due to the lack of natural damping. The front sprocket may start to wear out the counter shaft, causing it to eventually fail. A damped rear hub will counter this problem and also ease out the impact throughout transmission in general. I originally had a KTM damped rear wheel, which works fine. However, I splurged on a set of Haan Wheels hubs with a damped rear and Excel 18/21 A60 rims.

I don’t run tubes any more, as I seem to be having a lot of punctures due to excessive heat in low pressure. I’ve instead opted for Michelin mousses on AC-10 tyres. They are of course anything but ultralight, but the upside is that there is no need to carry spare tubes. Either way, I will next look into going tubeless, just as on my mountain bikes.

BRAKES

I love a clean office and modified the front brake to run rally style between the headlight mask and front fender. It does not interfere with navigation equipment and thus far has never caught on anything on the trail. The modification can be done with the OEM brake hose, and needs nothing more than patience and a few zip ties.

The rear brake is fitted with a thicker closed brake disk, to reduce wear on the rear brake pads. With the standard open brake disks, I’ve gone through brake pads in a single day of riding in wet and sandy conditions.

ENGINE OIL

I replaced the standard oil plug with the factory version, for extra durability and a smaller chance of the plug loosening and falling out. Theoretically the factory oil pump cover cools the oil a little, but it’s in fact there because it looks cool. Same goes for the orange oil filter cap. Guilty as charged.

The oil volume of the 500EXC has been debated until exhaustion, with different volume expansion methods from high volume clutch covers to external oil coolers. In fact I have a Twin Air oil cooler sitting in my garage, and despite the fact that it will add oil volume and reduce temperature, I never got around to fitting it. The reason I left it out is that it adds weight and four wet connections i.e. fail points. It requires special oil filters that are hard to find even in Europe. Additionally, it adds complexity to the oil change procedure and requires verification of oil flow, which seems close to impossible to do without removing the tank. So in my view that’s a lot of extra hassle and risks for a little bit more of oil. I’d rather just do oil changes more frequently

IGNITION MAP SWITCH

The ignition map switch is there to facilitate the change between standard and soft ignition maps. Most of the time I run on standard, but the soft map may be useful in technical terrain and if fuel quality is dubious or low octane. At least that’s what I’ve heard, and to be honest, I don’t feel any difference between the maps.

Steering damper

The Öhlins/Scott steering damper is quite a revelation. It does make the bike track really nicely on soft or rocky terrain.

INDICATORS

I went with some tiny LED indicators and a soldered LED indicator relay for the correct timing of the blink. The bike vibrates a lot so the cables need to be secured to avoid them shaking and getting cut. Also ,special care should be taken to ensure a snug fit inside the wheel well, to avoid the rear tyre contacting the indicator wires.

IGNITION SWITCH

The 500 only has a steering lock, but it’s essentially a tiny bolt within the steering head, and snaps off just by trying to move the bike while it’s locked. So it offers virtually no protection. Adding an ignition lock does not offer much ore protection, as there is really nowhere safe to mount it, where the wires could not be accessed. So I didn’t bother with an ignition switch, but did install a hidden ignition on/off switch. No pics obviously.

HEADLIGHT

The OEM light has been replace by the Dual.5 LED light by ET Racing. I have yet to test the light in riding conditions, but there is a lot of output compared to OEM headlight. See this post on the installation.

Although the light is absolutely stunning au naturelle, it needed a little extra protection. A standard KTM PowerParts headlight protector did the trick.

MIRRORS

The 500 came with two static mirrors. I prefer a clean cockpit when riding offroad, so I replaced the mirrors with a single Acerbic left hand side folding mirror. It’s mostly tucked away behind the hand guard.

SIDE STAND

The stock side stand gave up the ghost during the Crimson Trail, and I’ve since replaced it with a Hammerhead Side Stand. Bomb proof.

NAVIGATION

The bike has a single Garmin Montana 600 navigator. It’s locked into a powered Garmin cradle, which is held on the handlebar with a RAM mount. I keep the RAM mount loose enough to easily switch back and forth between seated and attack positions without needing to adjust the tension bolt. Power is run directly from the bike’s battery with a small fuse under the seat. There’s an on/off switch for the navigator, mounted directly to a bunch of wires with zip ties; keeping it ghetto.

ACCESSORY POWER SUPPLY

I have a single KTM PowerParts 12V socket on the number panel in the back of the bike. I can plug in a 12V USB adapter and charge whatever needs to be charged during the night in camp.

PANNIERS FOR EXPEDITIONS

I currently run with 2 x 10 litre XCountry custom Hobo version panniers and a Giant Loop ZigZag handlebar pouch. So a total volume of 20 litres for luggage.

The XCountry panniers mount on the bike without a rack, but need a tail mount point. I bolted some D-rings right on the tail fender with large washers, and so far they’ve been holding nicely. In the front the panniers are strapped right onto the frame.

After looking into several different pannier setups, I must say that the XCountry panniers tick all the essential boxes for me in ultralight expedition use. They’re light, waterproof, quick to open and close and sturdy. They are also easily expandable with the handy zigzag bungees on the outside. I regularly carry two 1.5 litre water bottles in the back at the end of the day before hitting camp.

The new version of the panniers also feature collapsible outside pockets, large enough to fit oil bottles. They are very handy for carrying liquids or other stuff that will potentially contaminate luggage.

PANNIERS FOR SHORT TRIPS

For one or two day trail riding outings, I prefer the ultra light Giant Loop Mojave saddle bag, and extend it with a Giant Loop Possibles roll top pouch when need be.

BOLTS

Many of the aftermarket stuff such as skid plates have different bolt head and types than the rest of the bike. I usually replace all after market bolts with high quality stainless steel hardware. I make sure the head is a Torx key size that I need to carry in my toolkit anyway.

HAUL LOOPS

The tail can be easily moved around from the luggage straps or just by grabbing the tail, so I only fit a haul loop in the front. It’s another ghetto edition, made from 25 mm webbing and some hardware. It does what it’s supposed to and tucks away nicely behind the headlight mask

Full service history

Check spoke tension
Check rim lock tension
Check valve nuts
Check coolant
Check steering limiters
Stabilize and protect wiring
Grease axles
Grease steering stem bearings
Adjust handlebar position
Anti seize brake pad pins front
Anti seize in triple clamp bolts
Align forks
Rear sprocket 50-T
Weigh bike

Anti seize chain adjuster bolts
Anti seize brake pad pins rear
Grease kickstand bolts and spacers
Grease countershaft
Front sprocket 13-T
Stabilize throttle cables to frame by seat bungs
Change oil and filter 1
Change oil and filter 2
Check valve clearances
Check valve shim sizes
Check radiator hose clamps
Secure starter relay with ziptie
Secure fuel pump relay with ziptie

Check radiator fan
Replace fuel prefilter
Adjust idle speed
Loctite kickstarter bolt
Loctite sprocket bolt
Loctite shock bottom bolt
Loctite chain guide bolts
Grease PDS hem joint (outside only)
Grease swing arm bearing
Mitas C-02 rear tyre
Headlight alignment
Electrical spray on all connectors
Full bolt check
Protect frame abrasion areas & recheck wiring stability
Check fairing screws
Tank protector rollers to radiator shroud tabs
MTB inner tube over fuel line quick release
Rear shock spring 80N/MM
Align forks
Tune suspension

Oil and filter change
Air filter change
Replace Hammerhead brake pedal tip bolts

Change oil and filter
Check valve clearances
Replace valve shim EX RIGHT
Check valve clearance EX RIGHT
Replace fuel prefilter
Replace air filter

Secure tank breather hose
Adjust idle
Front sprocket 13-T
Lock wire shifter pedal bolt
Loctite luggage strap bolts
Loctite panel bolts

Replace oil and filter
Metzeler Unicross tyres

Replace oil and filter
Replace air filter
Replace fuel micro filter
Check valves
Replace rocker arms

Rear shock service and preload adjuster
Fork service
Maxxis tyres
Replace rear brake disc
Replace coolant
Replace clutch fluid
Replace front brake fluid
Replace rear brake fluid
Grease rear wheel bearings
Grease sprocket carrier bearings
Rear tyre mud flap
Check the front brake linings
Check the rear brake linings
Check the free travel of the foot brake lever
Check the radiator fan

Adjust clutch and brake levers
Adjust throttle position sensor
Balance Haan wheels
Check the steering head bearing play and grease
Check and grease the swingarm bearing
Check shock bottom heim joint
Replace shock bottom heim joint
Replace rear sprocket 50T
Replace front tube
Replace rear tube
Check the spoke tension
Change spark plug
Replace chain
Check valves
Check clutch steel discs
Check clutch friction discs
Protect subframe abrasion
Check clutch pressure plate
Grease all moving parts
Check all hoses
Check cables for damage and protect routing
Full bolt check

Check suspension settings
Replace fuel filter
Replace air filter
Replace oil and filter
Replace power relay
Replace front sprocket 13T
Tune suspensions
Check electric problem 12 V USB outlet

Replace oil and filter
Replace air filter
Replace fuel filter in tank
Check valves
Check timing chain: excellent condition
Replace front brake disk
Check steering head bearing
Check clutch

Replace oil and filter
Replace air filter
Replace fuel microfilter
Install DIY kill switch
Replace front sprocket 13T
Wash air prefilter
Mitas C-02 rear tyre

Replace oil and filter
Replace air filter
Replace fuel microfilter
Wash air prefilter

Replace oil and filter
Replace air filter
Replace fuel microfilter
Wash air prefilter
Check and adjust valves
Replace rear brake pads
Replace front brake fluid
Replace grips
Replace foot peg cotter pins
Front sprocket 14t
Replace clutch master cylinder membrane
Full bolt check
Replace spark plug
Dunlop D606 tyres

Replace oil and filter
Replace oil sieves and caps
Replace air filter

Shock service
Replace fork seals
Clean forks
Replace fork oil
Fork Service
Replace spark plug
Replace spark plug connector
Replace rear shock bottom bearing
replace timing chain
Ignition cover gasket
Oil and filter
Replace brake fluid
Replace clutch fluid
Valve clearance check and adjustment
Remove navigation clamps
Short arm for Garmin cradle
Remove lower Garmin cradle
Remove Baja LED
Remove 12V outlet
Remove relay and reconnect headlight
Medium fuel tank
Replace in tank fuel filter
Fix sidestand
OEM plastic kit
Replace rear indicators

Replace tyres, Michelin AC10
Clean fork seals
Lube fork dust covers
Reattach valve case breather hose
Relocate temperature gauge
Navigator to handlebar
Oil and filter
Remove navigation panel
Remove navigation clamps
Clutch lever, orange
Brake lever, orange
Factory oil filter cover
Install mousses
Stickers on rim holes
Replace air filter
Lithium Ion Battery
Hammerhead brake pedal
Hammerhead shifter pedal
Hammerhead titanium pegs
Hammerhead side stand
Full titanium Akrapovic system
Install horn
Check headlight alignment
Check brake fluid levels
Check clutch fluid level

Install EnduroTech light mask
Replace front wheel bearings
Replace rear wheel bearings
Replace sprocket carrier bearings
RAM mount for fat bar
Replace swing arm bearings
Replace swing arm chain slide orange
Replace chain slide
Replace chain
Replace 13T front sprocket
Replace air filter
Replace air filter dust cover
Replace fuel micro filter
Replace footpeg pins
Replace fork oil
Replace white hand guards
Replace side stand bolt and other parts
Rewire navigator
Protect clutch hose
Tighten LED bolts
Secure LED ballast
Install rear indicators
Secure rear indicator wires
White tail section
Orange frame protectors
Seal steering lock from water to steering head bearings
White side sections