The KTM 450 series is a range of four-stroke enduro off-road motorcycles made by KTM. It comprises the road-legal European 400 EXC and 450 EXC and the American 450 XC and 450 XC-W, differing in gear ratios, lighting and suspension settings.
KTM 450 at a glance
| Maker | KTM, Austria |
|---|---|
| Type | four-stroke enduro off-road motorcycles |
| Models | 400 EXC, 450 EXC, 450 XC, 450 XC-W |
| European EXC | small headlight, speedometer, tail-light, softer PDS rear suspension |
| US EXC | 50-state street legal |
| First title | 1999 World Enduro Championship, 400 EXC |
| RFS engine | 2000-2007, 89 mm x 64 mm bore and stroke |
| 450 EXC | from 2003, longer stroke than the 400 |
| 2006 output | 42 hp (31 kW), 37.5 lb-ft |
| US street legal | 450 EXC from 2007 in full 50-state trim |
| XC4 engine | from 2008, 95 mm x 63.4 mm, about 51 hp (38 kW) |
| Fuel injection | from 2012 |
| 2017 chassis | WP XPlor 48 mm forks, PDS shock, 5 kg lighter |
based on one source
History of the KTM 450
2000-2002: the RFS years begin
The factory RFS (Racing Four Stroke) KTM 400 EXC won the 1999 World Enduro Championship. The 2000 RFS 400 EXC had a right-side kick-starter but also an electric start button. KTM took a different approach to the engine than most other manufacturers: where others used a 90 mm-plus bore with a very short 60 mm stroke, the KTM RFS motor used an 89 mm x 64 mm configuration that provided more torque at the expense of higher revs.
2003: the 450 EXC arrives
This was the first year of the 450 EXC. It evolved from the earlier 400 EXC with an increased displacement achieved through a longer stroke. The 2003 model saw an updated rear subframe, airbox and rear fender, one-piece side panels, changes to the fuel tank, seat and carburettor boot, and a front manifold changed from twin pipe to single.
2005-2007
These years brought a new frame that improved handling without major changes, and the rear bodywork changed to the single-piece design of the SX model. The 2006 450 EXC made 42 hp (31 kW) and 37.5 lb-ft of torque. 2007 was the first year the 450 EXC was offered in full factory 50-state street-legal trim: the conversion required changes in gearing, exhaust, DOT-approved tyres and lights plus the addition of turn signals and a horn, but the bike was otherwise virtually the same as the off-road-only machine. The US off-road-only EXC was replaced by the close-ratio XC and the wide-ratio XC-W. 2007 was also the last year of the RFS motor, a torquey and famously reliable unit; in some cases fully stock engines last more than 45,000 miles, and its wide-ratio six-speed transmission made it a good dual-sport and supermoto bike.
2008-2016
From 2008 the US version of the 450 EXC continued in street-legal trim but was replaced in the US market by the off-road-only 450 XC or 450 XC-W. A new chassis arrived in 2008 with improved suspension and handling, and the RFS motor, available in 250, 400, 450 and 510 cc between 2000 and 2007, was replaced by the XC4 engine. The XC4 450 has a 95 mm x 63.4 mm bore and stroke and produces about 51 hp (38 kW); reliability may have gone down, with some owners reporting top-end issues, and 2008 models had oil migration problems fixed for 2009.
2010-2017
The 2010 Champions Edition brought a new front Brembo caliper, a revised PDS needle design, a frame welded to the steering head 10 mm lower, a reinforced gearbox, a reworked chain adjuster and clamping rail and better timing chain tension. Oil pump gears, shaft, cover and O-ring were updated for 2011. For 2012 the range gained EFI fuel injection, a diaphragm-spring clutch and a lighter battery, and the XC(W) and XC(F) models both have a plug on the right side of the engine case for an optional kick-start lever. For 2017 KTM introduced a new chassis, motor and ergonomics with WP XPlor 48 mm forks and a PDS shock, saving 5 kg over 2016; the seat height was lowered by 10 mm to 38 inches and the foot pegs raised by 6 mm for better ground clearance.
Design and features
- RFS reliability: the 2000-2007 motor was famously torquey, with stock engines lasting over 45,000 miles.
- Road-legal EXC: the European EXC has lights and instruments; the US EXC became 50-state legal in 2007.
- XC and XC-W: close-ratio or wide-ratio gearboxes for off-road use.
- Fuel injection: from 2012, with a diaphragm-spring clutch.
KTM 450 versions
- 400 EXC: the 1999 title-winning RFS model.
- 450 EXC: from 2003 with a longer stroke, 50-state legal from 2007.
- 450 XC: close-ratio transmission, off-road only.
- 450 XC-W: wide-ratio transmission and softer PDS suspension.
The two-stroke relatives are the 300 and the 250; the larger four-stroke is the 500. More models are in the KTM collection.
Sources
- KTM 450 series, English Wikipedia: model progression, engines, output, street-legal trim
