KTM’s legendary EXC enduro range just keeps on getting better, the Austrian manufacturer packing a mighty punch when it comes to striving for ‘perfection’ in the world of off-road riding.

We may have only just entered the second half of this year, but already MotoOnline.com.au has been lucky enough to test and review the 2012 KTM EXC range at the brand new Wyaralong Moto Park just outside Boonah in Queensland between Brisbane and the Gold Coast.

The park, which is valued at over $3-million on a 745 hectare property, won’t be open until later this year, but selected members of the national press experienced a first look at what’s to come during the EXC range launch.

This week we’ll feature KTM’s four-stroke range – the 250, 350, 450 and 500 EXC-Fs – before next week we’ll turn our attention to the two-stroke range. In case you missed it, we already had a First Ride test of the anticipated 350 EXC-F just hours after we rode it last Friday (click here to check it out).

The Motorex KTM Off Road team has already been riding pre-production versions of the 2012 models in the Australian Off Road Championship, with Toby Price, Ben Grabham and Jarrod Bewley all racing their respective models into the winner’s circle on multiple occasions already.

Once we hit the trail, the main bike that everybody wants to find out more about is the incredible 350 EXC-F. At 350cc, it truly is the ultimate middleweight and KTM is confident that its capacity will be even more suitable for the bush than its Motocross World Championship-winning 350 SX-F sibling (thanks to Antonio Cairoli in 2010).

As suggested in our First Ride, the 350 truly is everything you’d expect when it comes to a mid-weight enduro weapon. It’s light, agile, and plenty powerful when you’re in technical surroundings.

What you will need to do compared to the higher-capacity bikes though, is ride it more like a 250F. You don’t have to rev it to the extent that you do an E1 bike, but there’s no denying that you’ll require more clutch use than a big-bore.

More importantly, does its handling advantage outweigh the sheer power and grunt of its big brothers, the 450/500 EXC? I personally think it does. On the open grass tracks you could take advantage of what the larger capacity bikes have to offer, but when it comes to the tight stuff they’re simply no match for the 350.

Over the long haul in a full day of riding, you’ll have to make your own decision what suits you more (or, will fatigue you less). Do you like a bike that is easier to handle and turn, but requires more focus on the engine rpm? Or do you prefer more power to chug along, even if the ride is slightly more taxing when it comes to turning? Well, option A is obviously the 350 and option B is the 450/500.

For me, I’ve always loved the 250 EXC-F, so having that extra touch of power while still retaining exceptional handling means that I’d lay my hard-earned on the 350 first and foremost.

Other first class points of the 350 is its ability to switch up lines at speed no matter the terrain your taking on. The only thing that could be improved here are more suitable tyres for your favoured trail, as the standard Metzelers aren’t quite as good as other offerings on the market.

I’d also suggest to get the suspension set to your ability and weight for personalisation, as at 72 kilograms the front did feel twitchy at times and slightly unstable at speed. The forks were just a tad harsh when I would hit the odd sharp bump, but the rear shock rode them well.

If you don’t want to use the clutch so much, I would have liked to try different gearing. With the standard gearing you almost never use first as it’s so short, and second gear is also really short. But then when you try to use third through the turns, it seems too tall unless you’re really on the gas. You could either add a tooth on and then try to use third more, or take a couple off and take advantage of the lower gears more often.

Once you get the gearing to your liking, you would find climbing tricky hills easier and even be able to conserve more energy on the exit of turns over a longer ride.

Overall though, the 350 EXC-F is an exception package that, when combined, may just make for the one of the most enjoyable enduro models we’ve ever got our hands on.

In saying that, the 450 and 500 were especially surprising during the test. In fact, I knew the 350 would be good after enjoying its motocross counterpart last year at its launch. What did shock me was just how great the big-bore models handled, and just how agile they were in their own right.

Straightaway on the grass track before I rolled into the single trail, I knew the 450 was supreme. It was the first bike I rode all day and, even though I was on an all-new trail, everything seemed so easy from the get go. That trait didn’t disappear either – every time I swung a leg over the 450 I was impressed with its improvements.

The brake distribution is phenomenal and the Brembo stoppers are as consistent as ever at the front, plus you just cannot beat the adjustability that Brembo offers for both the front brake and clutch regions.

That point actually applies to all of the models across the range, as does my appreciation for the clear fuel tank, electric starter, hydraulic clutch, standard hand guards and Stefan Everts-inspired slimline ergonomics,

Changing direction on the 450 is almost effortless, plus you can shift it into third gear and you’ll be able to use it pretty much anywhere apart from the faster sections.

Riding the 500 EXC offers an eerily similar feeling from many angles. It handles in an almost identical manner, albeit just half a kilogram heavier (111.5kg for the 500 vs. 111kg for the 450). The only place you can really feel an actual difference is in the change of direction.

Power-wise there’s five extra horsepower at the crank of the 500 (58hp compared with 53hp), plus an additional four Nm of torque (52 vs. 48). You can feel it, especially when cruising along, but unless you’re a heavier guy you probably won’t notice too many advantages. It’s a nice option to have though, and one that will only cost you an extra $200 (see full price list below).

I mentioned my love for 250s earlier in the piece, and there’s no doubt that the 250 EXC-F cements that admiration. There’s nothing quite like taking a bike and pushing it as hard as your ability allows, which is what this particular bike allows.

Its engine power, which honestly doesn’t feel too different to your average motocross model, is equally matched by its refined steering and stability at low and high speeds.

The gearing is spot on as you switch between second and third in most sections, and you’ll continually thank KTM’s engineering gods for the superb bottom-end and mid-range power they’ve extracted from the motor.

What you’ll like most on the 2012 model though is its electronic fuel injection. Yes, it is great on the larger capacity EXCs, but you notice it even more on the small-bore as you snap the throttle open to greater extents on more occasions on the 250.

Handling-wise, the steering is on point, but you do have to push it hard and ride aggressive if you want to keep up with your mates on the bigger bikes. It’s stable too, which means you can ride to the edge and the bike will usually react with great forgiveness.

KTM has created a massively impressive model range here in 2012, and this is only the four-stroke range. You can pick the 250 EXC-F up for $11,995, the 350 EXC-F will set you back $12,495, the 450 EXC $12,795 and the 500 EXC $12,995.

Prices listed are recommended retail prices and exclude dealer delivery or on-road costs.

All models are expected to commence rolling into Australian dealerships in late July/early August 2011.

Technical Information

Chassis Overview
After adopting linkage on their motocross chassis in 2011, some expected the enduro version to follow suit for 2012, however that’s not the case as KTM firmly believes that the PDS system is better for off-road riding – namely because they say a linkage can be damaged in hardcore off-road sections.

Still, the 2012 EXCs have completely new frames – three years in development – with a further developed PDS rear suspension system for all EXC models. Following the proven KTM tradition, the frames are made of high- quality, lightweight chrome-moly steel material in various profiles.

Compared to the previous EXC frames, this frame design provides higher torsional and reduced longitudinal stiffness, providing better track stability in conjunction with improved handling. In addition the chassis is specifically designed to absorb energy created from the rear wheel impacts.

According to KTM’s press kit, the EXC frame weighs approximately 0.5-kilograms less than its lightest competitor, while also stating that it’s easier to maintain and work on.

The new EXC models are fitted with a seven millimetre longer PDS shock made by WP Suspension and a further developed geometry (the shock is mounted flatter compared to 2011) to offer an improved rising rate character.

It is fitted with an improved piston and bushings that provide better seal and friction properties to handle the higher shaft velocities. A new spring retention and preload system allow preload adjustment without the use of hammer and punch.

All models are fitted with a new cast aluminium swing arm. The single-component casting process allows unlimited geometry solutions and eliminates any inconsistencies created by welding. Updated mounting positions, slightly higher profiles and optimised flex support the frame and suspension characteristics. The swingarm is 300 grams lighter than 2011.

Also on all models, WP’s latest generation 48mm USD forks are now fitted with new seals and improved bushings. There are new settings featured throughout the range.

The bodywork of the new EXC line-up has already proven its qualities on the 2011 SX models. Super slim ergonomics and excellent contact points between rider and machine were a major target set by 10-time Motocross World Champion Stefan Everts.

Everts also insisted on having a wider and 50mm longer rear fender, which is fitted with a new number plate support for enduro. There’s also a fresh new ‘lift handle’ in the outer rear fender.

A new airbox is fitted, driven by two main functions – optimised protection for the air filter against dirt and maximum airflow for increased performance. The engineers designed different intake boots for every displacement, which improve the power significantly.

The four-strokes have new and improved silencers that have a larger profile to reduce the noise level to the FIM noise emission regulations at 112dB. Instead of muffling performance, the bigger exhaust has allowed KTM to simply add more packing for the quieter note.

The high-quality KTM wheels with CNC machined hubs are now silver, assisting in keeping them looking good on the trail. What’s more, the spokes are now covered with noble zinc/nickel coating to improve corrosion resistance. With new nipples made of high-strength aluminium the weight could be reduced by 200 grams per wheel.

KTM’s proven integrated cooling system routes from the cylinder head through the frame triangle directly to the radiators, and the removed tubing simplifies the radiator mounting and improves the air flow through the radiators. A new T-connector with an optimised fluid flow improves the heat dissipation. The 450 and 500 EXC are also fitted with a radiator fan in serial production.

Other impressive standard features that come standard on the EXCs are a hydraulic clutch, Brembo brakes, tapered aluminium handlebars and Renthal grips. In addition there is the high-quality robot welding of frames and a KTM tool kit, which allows disassembling nearly the whole bike due to special standardised screws.

The nine-litre tanks are made from lightweight translucent polyethylene, and the four-strokes are fitted with the latest version of fuel pump. In the PowerParts catalogue there are also 13-litre tanks available for all models.

350 EXC-F Engine Overview
When compared to the 350 SX-F, this is a new DOHC powerhouse that has been especially developed for enduro. The 350cc four-stroke engine delivers a very broad and tractable power band and a very dynamic, but energy-saving engine characteristic.

At 349.7cc, with a claimed peak performance of 47hp and 37.5Nm of torque, the 350 is designed to take on the 450s in the E2 class. It’s ultra-compact with 57.5mm stroke and 88mm bore, with similar dimensions to the 250 EXC-F.

The newly developed engine management system by Keihin with electronic fuel injection and 42 mm throttle body secures spontaneous and powerful response and maximum performance. Automatic temperature and altitude compensation are state of the art.

Time consuming re-jetting of carburettors or engine stalls during fast throttle openings are a thing of the past, and an optional map selector switch gives the option of selecting three additional different mappings, changing the engine characteristic.

In addition to this, the user-setting tool available through PowerParts allows data logging and also to change the ignition and the EFI mapping in just a few mouse clicks.

The DOHC cylinder head is fitted with four ultra lightweight titanium valves (intake 36.3mm, exhaust 29.1mm), which amounts to a rev limit of 12,000rpm – 1000rpm less than the SX-F. New camshafts are developed enduro specific low-end performance. In addition the EXC cylinder head is fitted with slightly softer valve springs, adapted spring retainers and new spring seating washers.

A new piston offers less compression than the SX-F, combined with a longer cylinder to reduce the compression ratio from 13.5:1 to 13.3:1. The crankshaft turns an intermediate gear, which drives the cam chain and at the same time acts as balancer shaft and holds the water pump. A hydraulic cam chain tensioner secures a reliable tension of the chain and therefore precise cam timing.

Compared to the SX-F model, the 350 EXC-F is fitted with a new crankshaft with heavier crank webs in order to provide more inertia for smoother power delivery and better traction. It has a balancer shaft on the right side of the engine, which also acts as a water pump intermediate gear and drive pinion gear for the camshaft.

The engine has two oil pumps, similar to the 250cc engine. A pressure pump supplies the crankshaft, piston, balancer shaft, chain tensioner and valve train. Additionally it supplies lubrication for the clutch and cools the ignition. A suction pump evacuates the crank housing and lubricates the gearbox. It creates a vacuum in the crank housing to increase the engine performance.

There’s a 196W alternator with an integrated one-way clutch for the electric starter. This new alternator secures enough energy for the fuel injection system and lights, etc.

A new one-piece clutch basket combined with the primary gear is made of high-strength billet steel. KTM claims it guarantees unbeatable reliability and contributes to the narrow engine size due to its compact rivet-less design. Additionally, it allows the use of thinner steel linings, which makes the whole clutch package noticeably narrower.

Compared to the SX-F clutch, a newly developed diaphragm spring makes it possible to implement an additional rubber damping system, guaranteeing more reliability for the transmission and better traction. The hydraulic clutch by Brembo in conjunction with the diaphragm spring guarantees a very light operation and good controllable modulation of the clutch.

250 EXC-F Engine Overview
The 250 EXC-F has always been known for its strong performance and it has won several Enduro World Championships. The new generation presents itself with a further developed, even stronger engine including fuel injection. This is a major step forward to make this agile and lightweight enduro machine even more competitive in the future.

The heart of the compact engine is the cylinder head with two overhead camshafts and DLC coated finger followers, which activate the four titanium valves (intake 30.9mm, exhaust 26.6mm).

An optimised, fluidic developed (flow calculation & simulation) intake channel provides 10 percent more gas flow and therefore significantly increases
the performance. The intake camshaft is carried over from 2011, while the exhaust camshaft features an optimised automatic de-compressor profile.

You’ll enjoy both an electric and kick-starter. A new kick-starter provides less weight and better ergonomics. The new electric starter system is similar to the one of the 350 SX-F/EXC-F and is now connected via the alternator cover.

Also like the 350 engine, there’s the Keihin EFI system, which comes as a vital addition of the 250. The EMS also features almost identical adjustments to the 350’s.

You’ll also find the same alternator that’s featured on the 350, up to 196W from 130W.

450/500 EXC Engine Overview
For years KTM has set the benchmark amongst the large capacity four-strokes, but with the newly developed 450 and 500 EXC (449.3/510.4cc), KTM claims they have set a new standard in their classes. Take note that the 500 still has the came capacity as the 530 EXC of 2011.

The new SOHC engines feature an extremely compact design, easier maintenance, improved durability and a massive weight reduction of 2.5 kg to the predecessor. Together with the new EFI system on both engines, KTM says the 450 and 500 provide unrivalled enduro specific performance and rideability.

Compared to their predecessor, the new engine generation features a brand new engine design. Due to an improved packaging, the dimension of the engine casing could be reduced drastically – a major advantage is the higher ground clearance, the frame tubes are higher due to the very compact engine.

One reason is the switch from a central balancer shaft to a lateral balancer shaft with an integrated water pump. In addition, the casing is now produced in die-cast instead of sand-cast, so that the wall thickness could be reduced for weight saving without reducing strength.

A special high-strength aluminium alloy guarantees high ductility for maximum safety against damage. In order to make the engine more user-friendly, the new generation features one common oil circuit. This new package results in an amazing weight reduction of 2.5 kg compared to the predecessor.

The cylinder has the same bore as MY2011 with 95mm, but is now fitted with a mechanical cam chain tensioner (instead of hydraulic) and new chain guides. New, lighter pistons for each model contribute to the low vibration level. They are fitted with new high-performance piston rings for reduced blow-by and less oil consumption.

The outer shape of the SOHC cylinder head with titanium inlet and steel exhaust valves is basically the same as before, but the internal design has been redesigned completely. Flow-optimised inlet and exhaust ports together with an improved design of the combustion chamber have been developed to best suit the new EFI system for outstanding power delivery and performance.

The camshafts are carried over from the predecessor, while a new design of the water jacket in the cylinder head provides a better heat transfer, which is even safer with the standard radiator fan.

The crankshafts, with 63.4mm stroke for the 450 EXC and 72mm for the 500 EXC, are equipped with a new ultra-light connecting rod produced from special high-grade steel by Pankl. This guarantees highest precision and reliability.

Due to improved materials and the sophisticated design, the KTM engineers managed to reduce the oscillating masses in the engines drastically (the 450 by -15 percent and the 500 by -20 percent). Therefore it was possible to mount a smaller, 0.5 kg lighter, laterally located counter balancer instead of a central one, which would need much more space. It is also designed to hold the water pump wheel.

The new engine family features a newly designed oil circuit with two instead of three oil pumps and only one common oil circuit. The pressure pump lubricates the conrod bearing, balancer shaft, valve train and supplies oil for piston cooling. The suction pump evacuates the crankcase from blow-by and oil. It lubricates the clutch and the transmission.

Just like the 250 and 350 EXC-F, the 450 and 500 EXCs feature the Keihin EMS with EFI and 42mm throttle bodies, plus along with all four-stroke models, there’s the 196W oil-cooled alternator. Again, there’s an optional map select switch and the user-setting tool are available in the PowerParts catalogue. Also like its smaller 350 EXC-F, the big-bores feature the same one-piece clutch as well as the features that go alongside it.

The 450/500 EXC are also fitted with both an electric and kick-starter in serial production. Basically the electric starter system was carried over from 2011. The new engine features a smaller and lighter starter motor and a new kick-starter.

Click here to check out a full image gallery of the 2012 KTM EXC range.

For further technical information and full specifications on the models, visit www.ktm.com.au.

Rider Wear (click to read our reviews in the Product Centre)
Jersey/Pants/Gloves: FOX Platinum Race
Helmet: FOX V3 Carbon
Goggles: Oakley Mayhem
Boots: Alpinestars Tech 10
Neck brace: Alpinestars Bionic Neck Support
Knee brace: PodMX K700

Do you have an opinion to share on this story? Be sure to sign up to MotoOnline.com.au’s iMoto Community and have your say below today!