KTM 450 SX-F
By TMX Archives on 2nd Jul 08
The logical place to start on my rundown of KTMs finest is the big flagship 450 SX-F, and what great place to start. Its 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.
Specification:
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
