KTM puts best foot four-ward
By TMX Archives on 2nd Jul 08
AFTER four successive years of radical re-development and re-invention that has seen brand new motorcycles debuted every year, every single machine in its comprehensive SX motocross range rebuilt from the ground up, and firmly placed the company at the very fore-front of modern off-road technology, refinement rather than further radical departure has been the name of the game for Austrian giant KTM on it's 2009 year motocross machines.
Blazing a trail over the past few years to bring myriad developments and new ideas that resulted in more annual changes and modifications than its Japanese rivals manage combined, the always ambitious and maverick KTM factory has reached a point with its 2009 models chassis and engine development, on the four-stroke 250 SX-F and 450SX-F models in particular, where it feels minor refinement will keep the bikes at the front of the pack. And after the huge efforts of the past few years it is easy to see how this can be the case.
This is not to say KTM has rested on its laurels and taken a year off, however, and alongside the development of the completely new 65 SX Youth machine, the 200 plus staff in KTM's R&D department has been busy making small but significant modifications here and there to ensure that the 2009 machines are better performing and more reliable than ever before.
The factory Red Bull KTM team has very much been an inspiration to the designers of the 2009 four-stroke models and while customers my not have massive motor mods to get excited about, KTM has certainly offered them something different as both the 450 SX-F and 250 SX-F come as standard kitted out with a factory team inspired look that includes a special graphics kit, factory style orange triple-clamps, SXS handguards, an SXS seat, and aluminium skid-plate.
That is not where the similarities with the factory team machines end as the 450 SX-F now comes equipped with a titanium header pipe that features resonator chamber similar to that on the factory machine which helps to reduce the noise out put by two decibels.
The big flagship DOHC model also benefits from two new camshafts with lighter springs for what KTM claims ensures more power right through the rev-range.
The 250 SX-F also receives new camshafts for increased responsiveness and bottom-end power while new valve springs contribute to minimise oscillating mass for less vibration and better durability. The bike also receives a strengthened third and fourth gear for improved shifting and longer life.
Both the four-stroke models share with the three two-strokes a new Magura hydraulic clutch master cylinder which produces an improved engagement, while a new 'flex' lever is also fitted as standard which bends 90 degrees forward in crash situations to limit the possibility of lever breakage.
Also shared between all the SX models are new factory style engine covers, new front suspension settings for the closed-cartridge 48mm WP units that pertain to better dampening and sensitivity, a new setting for the WP PDS rear suspension unit, a new Brembo front brake unit that retains its infamous stopping power whilst improving feel at the lever, and the latest generation Excel wheels.
The two-stroke hardcore will be delighted to learn that the trusty smokers have seen the most development at Mattighofen. SX sales may be 60/40 in favour of the thumpers but KTM's fine tradition of producing fire-breathing two-strokes remains firmly intact and it is committed to keeping the two-stroke going. There were even whispers of new machines in the next year.
The 125 SX and 150 SX - still a 144cc but re-named to help in the US market where rules now allow 150cc machines - both receive a new cylinder yet again, the fourth in four years for the 125, this time with a modified exhaust valve area that promotes a wider opening for improved bottom-end power. Tied in with this is a new 38m Keihin carb, down from 39mm, which KTM has managed to utilise to boost responsiveness and power delivery low down whilst maintaining overall power output higher in the rev-range. The 150 SX also receives two new power curve settings.
Launched to the European press last week in the scenic setting of the Linkoping, Sweden, I was keen to put the '09 range through their paces after enjoying the fruits of KTM's labour the past few years and again I was very impressed by the Austrian concerns output.
KTM 450 SX-F
THE logical place to start on my rundown of KTM's finest is the big flagship 450 SX-F, and what great place to start. It's a fantastic 450cc machine.
Just two years into it's production run after a total re-design the 450 SX-F unsurprisingly recieves little in the way of modifications, save for the new camshafts and exhaust header, and the across the board revised suspension settings, but KTM has added value and desirability to the 450 SX-F with the addition of the 'factory' race package that adorns the bike.
The addition of graphics, SXS seat and orange triple-clamps, ally skid-plate and SXS handguards gives the bike a really strong, impressive look in the flesh and although it does not impact the overall performance of the bike it shows that KTM is thinking about its customers and giving them value for money. And at a time when there really is no such thing as bad 450, and money is tight, the fact that KTM is offering riders a proper graphics kit and some usual aftermarket parts as standard is a positive. Big tick to KTM.
On the track the bike gets a similarly big tick. It's a cracker, combining smooth yet undeniable power with solid handling and impressive cornering prowess. And the electric-start is a god send that really should be standard on all 450's if you ask me.
The motor is a classic big four-stroker and one with which KTM has pulled off the neat trick of producing the smoothest, most forgiving and useable motor in the class whilst also being a contender for most powerful also, making the 450 SX-F a bike that produces superb traction and manages to appeal to both the average club level rider and hard-riding Expert level pilots equally.
The new camshafts improve power at low-revs in particular says KTM, but, aided I think by the addition of the resonating chamber on the exhaust header which has helped to smooth off the power delivery slightly as well as lower noise, any particular power gains are not really noticeable and the bike retains it's very smooth and very useable power delivery.
Don't get me wrong the power is there in abundance but it never hits too hard and whether you roll on the throttle gently or as hard as you can the bike manages to find grip and drive smoothly forwards.
The continued use of a four-speed box helps the smoothness of the motor and traction at the rear-wheel I think also. Four-speed boxes have been dropped by the rest of the big-five and they are not to everyones taste, but I think it works for the 450 SX-F. All four gears are still useable out on the track - you only get four useable gears on a five-speed really anyway - third gear in particular is really long and pulls forever, and the progression between each gear is very smooth and linear with no discernible jump. The length of the gears actually helps keep things smooth in a lot of situations too, allowing you to hold a gear just a bit longer and thus eliminate the need to shift up and then bang it back down through the box. This promotes a smooth, more flowing riding style which is how the 450 SX-F likes to be ridden really.
The smoothness of the motor would be nothing without a good chassis and the KTM frame and chassis set-up is very forgiving indeed. The tried and trusted steel frame may not be the most high-tech or in vogue but it does produce the most feel and feedback of the current crop of 450 frames and this translates into impressive traction and very good handling for such a big bike.
I don't think it turns quite as fast as the CRF 450, but it is right up there with the best in class in the cornering and handling department, changing direction well and holding lines well, and in faster sweeping corners in particular the bike excels.
The very open, neutral and comfortable ergonomics that the chassis redesign of two years ago promote contribute to this significantly also.
The revised WP suspension settings are another step forward and the rear PDS unit in particular now is very good indeed. The PDS system has been much maligned in the past but really now I feel out of the crate it works just as well as anything the Japanese put on their machines and in particular its ability to cope with small choppy stuff is very good.
The front too soaks up the smaller stuff very well indeed, making for a bike that tracks down straights very well and doesn't get out of shape very easily, but I would say that it was maybe just a bit too soft on the bigger landings. This quickly remedied though.
As you would expect from KTM the brakes and hydraulic clutch action were superb, and the fearsome front Brembo is noticeably more progressive thanks to the new master cylinder which is a nice development.
All in all the 450 SX-F is a superb 450 and if you are looking for super-smooth power this is your bike.
KTM 450 SX-F
ENGINE
Type: Liquid-coold single cylinder, DOHC 4-stroke
Displacement: 449.3cc
Bore x Stroke: 97/ 60.8mm
Compression Ratio: 12.5:1
Carburettor: Keihin FCR-MX 41
Starter: Electric starter/ 12V 4 Ah
Gearbox: Four-speed
Clutch: Wet multi-disc clutch, hydraulically operated
Lubrication: Pressure lubrication with 3 oil pumps
Primary Drive: 29:74
Final Drive: 14:52
Ignition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, Aluminium 28/ 22mm
SUSPENSION
Front: WP-USD 48mm
Rear: WP-PDS shock absorber
Travel Front/ Rear: 300/ 335mm
BRAKES
Front/ Rear: Disc brake 260/ 220mm
WHEELS
Front Rear: Excel 1.60 x 21"; 2.15 x 19"
DIMENSIONS
Steering Head Angle: 63.5°
Wheelbase: 1,475mm
Ground Clearance: 380mm
Seat Height: 985mm
Fuel Capacity: 8 litres
Weight (without fuel): 104.6kg
KTM 250 SX-F
YOU just have to open your eyes in any motocross paddock to see how popular the 250 SX-F is and read through the results from any British championship or GP round to see just how successful the bike is too, and its no surprise as the 250 SX-F is a superb motorcycle and one of, if not THE best 250F on the market currently.
And it is no surprise to find little different on the '09 model either.
Owner of a very powerful, incredibly torquey motor and a superb handling capabilities already, the 2009 version of the 250 SX-F continues very much in this trend and thus remains right at the top of the 250F tree.
As with its bigger brother, little has changed in the motor department of the 250 SX-F, but the one significant change - the addition of new camshafts - adds to motors strengths further still.
Very powerful yet incredibly smooth, tractable and torquey in its delivery, like a small 450 almost, the motor has always been probably the strongest perfomer in its class since its inception, and now thanks to the new camshafts the bikes responsiveness and low-end grunt has been enhanced just that bit further to keep it at the head of field. It's not a huge advancement but it is noticeable and helps fire you out of corners and pick-up on landing from jumps just that tiny bit better.
It is a very easy motor to feel comfortable with and one that flatters the rider, inspiring confidence and the riders willingness to push harder and longer. The smoother and more flowing you are on a bike in general the more rewarding the 250 SX-F is too and if you keep the bike in the meat of the torque range as you go up and down through the excellent six-speed gearbox rather than rev the crap out of it there is no other bike in its class that is more rewarding and responsive to ride.
Similarly to the 450, the small changes made to the suspension and chassis further improve the handling and ride of the 250 SX-F a small amount and ensure that it keeps up with the competition and remain of one the best cornering bike sin the class. The room the 250 SX-F affords you in corners and its very slim nature promote aggressive cornering and combined with how planted and stable the frame is the bike handles like it is on rails.
Again like the 450 it is very good indeed when you get the weight on the rear-end and power through sweeping corners, finding traction and holding the line superbly, and the new rear PDS settings have helped this considerably. The bike sits brilliantly in corners too, giving confidence to hit them harder.
The front too is improved, particularly in its ability to soak up the smaller stuff early in the stroke, allowing for a more confidence inspiring front-end ride than in previous years, and unlike the 450 SX-F it felt just about perfect on its dampening and rebound on the bigger hits making for a cracking all round suspension performance to match an already superb motor and true factory look. Take off the unwieldy handguards and you have my favourite 250F on the market.
It remains an MX2 leader.
KTM 250 SX-F
ENGINE
Type: Liquid-cooled single cylinder, DOHC 4-stroke
Displacement: 248.6cc
Bore x Stroke: 76/ 54.8mm
Compression Ratio: 12.8:1
Carbrettor: Keihin FCR-MX 39
Starter: Kickstart
Gearbox: Six-speed
Clutch: Wet multi-disc clutch, hydraulically operated
Lubrication: Pressure lubrication with two oil pumps
Primary Drive: 22:68
Final Drive: 13:48
Ignition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, Aluminium 28/ 22mm
SUSPENSION
Front: WP-USD 48mm
Rear: WP-PDS shock absorber
Travel Front/ Rear: 300/ 335mm
BRAKES
Front/ Rear: Disc brake 260/ 220mm
WHEELS
Front/ Rear: Excel 1.60 x 21"; 2.15 x 19"
DIMENSIONS
Steering Head Angle: 63.5°
Wheelbase: 1,475mm
Ground Clearance: 380mm
Seat Height: 985mm
Fuel Capacity: 8 litres
Weight (without fuel): 98kg
KTM 250 SX
IT is perhaps a sign of the times - KTM's sales ratio is 60/ 40 in favour of four-strokes - and maybe the fact also that the bike has never really captured the public's imagination, that the 250 SX remains the only bike on the KTM roster unchanged for 2009 in the engine department. Yes it gets the new suspension mods but it is essentially and unchanged bike for 2009, but that is not to say the bike does not have a place in the market or not worthy of consideration. It is a good 250cc machine, and horse power fans will love the bike.
During the early years of its development the 250 SX developed somewhat of a reputation as a bit of an animal with a wild hit of mid-range power that make it real handful to even the best 250cc runners, but KTM made considerable effort to smooth off the bike in recent seasons and the effort has worked to the extent that the 250 SX is now a very competitive and rideable 250cc machine.
The power is still there in abundance, especially when you get it wound up, but despite the strength of the power there is linear transition from the low to mid-range which drives the bike forward rather than spinning up and creating problems. Get used to the sheer power of the bike, or any 250 really, and it becomes a very rewarding ride though, particularly as it feels so light and nimble in turns and in the air at a sprightly 98 kilos.
The handling has been improved significantly on the front-end of the 250 SX, however, thanks to the new front suspension. Previous incarnations were always a little oversprung, which when combined with the fiery power made for a very light front-end that chopped around without much asking, but the softer settings and improved action afforded to all the bike have paid dividends for the '09 250 SX and the whole bike feels considerably more stable and planted at speed and in turns. Result.
KTM 250 SX
ENGINE
Type: Liquid-cooled single cylinder, 2-stroke
Displacement: 249cc
Bore x Stroke: 66.4/ 72mm
Carburettor: Keihin PWK 36 S AG
Starter: Kickstarter
Gearbox: Five-speed
Clutch: Wet multi-disc clutch, hydraulically operated
Lubrication: Mixture oil lubrication 1:40
Primary Drive: 26:76
Final Drive: 13:48
Ignition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, Aluminium 28/ 22mm
SUSPENSION
Front: WP-USD 48mm
Rear: WP-PDS shock absorber
Travel Front/ Rear: 300/ 335mm
BRAKES
Front/ Rear: Disc brake 260/ 220mm
WHEELS
Front/ Rear: Excel 1.60 x 21"; 2.15 x 19"
DIMENSIONS
Steering Head Angle: 63.5°
Wheelbase: 1,475mm
Ground Clearance: 385mm
Seat Height: 985mm
Fuel Capacity: 8 litres
Weight (without fuel): 95.4kg
KTM 125 SX/ 150 SX
THE off-road press have run out of superlatives to describe the 125 SX and it's recent new sibling the 150 SX over years and one lap on either bike tells you exactly why this is the case - they are both hands down among the very best motocross machines on the market whatever stroke or capacity.
The 125 SX has been at the top of the two-stroke tiddler tree since before the turn of the millennium and despite the best efforts of the powers that be and the Japanese to marginalise 125's KTM has continued to forge ahead with two-stroke development year after year, reaping the rewards in strong sales and rave reviews about a pair of bikes that epitomise just what is so great about two-strokes.
2009 is no different and once again KTM has eked a bit more power, a bit more smoothness, and a bit more enjoyment out of its most beloved bikes.
Although the 125 SX and 150 SX benefit from different cylinders the performance of both is very similar in general and both recieve a significant boost in performance from the addition of yet another new cylinder and the smaller 38mm Keihin carb unit.
Increased bottom-end power without sacrificing overall power was what KTM were searching for with both of the developments and they have delivered here making both bikes noticeably stronger off the bottom-end and through the mid-range, requiring less clutch to keep on the boil and making for a smoother ride, and again a small step closer to the four-strokes.
The 150 SX in particular is impressively stronger right off the bottom and pulls quicker and stronger through the rev-range out of corners. The power delivery on both bikes though is more linear, progressive and manageable right the way through the range as a result of the increased bottom-end and it is easier to keep the bike in the meat of the power.
The performance from the mid-range upwards is as formidable as ever and when you get both bikes into some grippy soil or upright and in a straight line up through the gears the over-rev is really sensational and you can pull gears for what seems like an eternity. This is where the 150 SX especially stands out above its smaller sibling, pulling impressively longer and harder.
What really stands out on both bikes to me though is just how controlled and progressive they are despite their very strong and fiery power. The torque is impressive and they are eminently rideable, and combine this with the already superb handling and forgiving chassis that has already been talked about and you have a pair of bikes that handles better than any other in the KTM range.
The traditional steel chassis is the perfect match for a 125cc or 150cc engine and offers incredible feel and stability in corners, and the super-light 90kg weight means the bikes are a dream to attack corners and ride aggressively with, and the revised suspension front and rear both bikes provide a more supple, positive and balanced ride, particularly on the front-end which benefits from the slight
softening that all the bikes seem to have, and makes holding lines and attacking rough sections a more enjoyable and rewarding experience.
The 125 SX and 150 SX are thoroughbred racers and really it is hard to find fault with either machine without getting really, really picky. Without doubt you'd be hard pushed to find a more enjoyable and fun motocross bike to ride all year.
KTM 125/150 SX
ENGINE
Type: Liquid-cooled single cylinder, 2-stroke
Displacement: 124.8cc/143.6cc
Bore x Stroke: 54/ 54.5mm/56/58.4mm
Carburettor: Keihin PWK-S 38 AG
Starter: Kickstart
Gearbox: Six-speed
Clutch: Wet multi-disc clutch, hydraulically operated
Lubrication: Mixture oil lubrication 1:40
Primary Drive: 23:73
Final Drive: 13:50/14:50
Ingnition: Kokusan
CHASSIS
Frame: Central double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, Aluminium 28/ 22mm
SUSPENSION
Front: WP-USD 48mm
Rear: WP-PDS shock absorber
Travel Front/ Rear: 300/ 335mm
BRAKES
Front/ Rear: Brembo disc 260/ 220mm
WHEELS
Front/ Rear: Excel 1.60 x 21"; 2.15 x 19"
DIMENSIONS
Steering Head Angle: 63°
Wheelbase: 1,471mm
Ground Clearance: 390mm
Seat Height: 985mm
Fuel Capacity: 8 litres
Weight (without fuel): 90.8kg
KTM 65 SX
THE most radical bike in the KTM range is not from the full-sized SX models, but the brand-new version of the all conquering 65 SX which was unveiled at the same launch and featuring a unique engine layout among off-road machines.
Already having virtually eliminated the venerable KX65 from the Junior ranks in recent years thanks to its superior motor and chassis package, the bike gets a total re-working with nothing left remaining from the old machine and a brand new motor featuring the gearbox mounted underneath the crank and a cylinder laid over at 45 degrees taking pride of place inside a brand-new frame.
In a design strikingly similar to the prototype four-stroke Husaberg motor developed by KTM - who own the name - this year, the 65 SX motor had been designed to seriously boost power output and centralise mass, and thus the crankshaft is hoisted upwards and angled forwards towards the centre of gravity, benefiting the handling and responsiveness of the bike, while the gearbox is moved directly underneath, allowing for a straighter angle for the intakes and reed block for improved performance.
A new powervalve has also been built into the motor to boost overall power and torque, and a new flat-slide 24mm Mikuni carb is also added along with the lastest generation V-Force reed block and new exhaust system to further aide throttle response and overall power.
The end result is a motor that produces significantly more power right the way through the rev-range and at the bottom and top-ends in particular.
To ensure the rider gets the best out of the new motor on the track a totally new chassis has been developed also with a brand new frame built using KTM's latest frame building technology, and new full-adjustable 35mm Marzocchi forks and revised WP shock fitted.
A new four-piston rear-brake is fitted to the new black wheels, while the newly designed bodywork mimics that of the full-size SX models and promotes much improved ergonomics and rider comfort. Pro Taper handlebars finish off the whole package which is sure to be at the top of every young racers wish list when it arrives on UK soil in the very near future.
KTM 65 SX
ENGINE
Type: Liquid-cooled single cylinder, 2-stroke
Displacement: 64.9cc
Bore x Stroke: 45/ 40.8mm
Carburettor: Mikuni VM 24-505
Starter: Kickstart
Gearbox: Six-speed
Clutch: Wet multi-disc clutch, hydraulically operated
Lubrication: Mixture lubrication 1:60
Primary Drive: 23:75
Final Drive: 14:50
Ignition: AET digital
CHASSIS
Frame: Double grinded central double-cradle-type frame
Subframe: Aluminium
Handlebar: Pro Taper, Aluminium 22mm
SUSPENSION
Front: Marzocchi-USD 35mm
Rear: WP mono-shock
Travel Front/ Rear: 220/ 270mm
BRAKES
Front: Disc brake, 198mm
Rear: Disc brake, 160mm
WHEELS
Front/ Rear: 1.60 x 14"/ 1.60 x 12"
DIMENSIONS
Steering Head Angle: 64.5°
Wheelbase: 1,137mm
Ground Clearance: 280mm
Seat Height: 750mm
Fuel Capacity: 3.5 litres
Weight (without fuel): 55.4kg
Specification:
