Engine:

• Totally new engine based on KTM's new generation 250 2-stroke
  
• Compared to 2003: 3.5 kg (7.7 lbs.) engine weight reduction due to smaller, more compact engine and frame geometry
  
• Boyesen intake reed case
  
• Dual-ring pistons for longer life and reliability
  
• Cylinder head combustion chambers specially designed for cross country racing
  
• Kokusan 2K3 ignition system feature roomier ignition cover
  
• Digital box programmed with special cross country type ignition curve
  
• 5-speed transmission features close ratio gearbox
  
• Keihin PWK 36 AG carburetor

Exhaust:

• The 300 exhaust system is a totally new design, offering a perfect fit for the new engine setup. Additionally the system is equipped with a new shorter silencer - this combination results in a wide, usable powerband.

Frame:

• High-end chromoly frame features reduced wall thickness and lower overall weight – now less than 9 kg (20 lbs.)
  
• New forged swingarm support and footpegs provide a narrower, lighter weight and flatter profile.
  
• Reinforced steering head area affords more reliability

Swingarm:

• Swingarm pivot increased 2 mm to 17 mm diameter (stiffer and less weight)
  
• 10 mm longer swingarm on all 2004's delivers better traction and more room for rear wheel movement

Fork:

• Newly adjusted WP 48 mm USD fork features three bushings – fork is more supple and offers greater sensitivity

Shock:

• Improved sensitivity and increased bottoming resistance by use of an optimal setting and a linear wound main spring

Front Brakes:

• The MXC models have new brake discs with round holes for weight reduction, less wear and lower operating temperature

Rear Brakes:

• The MXC models feature similar brake discs to the SX with round holes
  
• MXC models share the same integrated reservoir foot brake-cylinder and 26 mm brake caliper as the 250 SX 2003

Wheels / Tires:
EU:

• DID rims
  
• High-end Pirelli MT 83 competition tires

Body work:

• One-piece rear fender / side panel combination –same as last year's 250 SX and 450 SX –for all models
  
• Lower subframe for better handling
  
• All seats have a new seat base, anchored by a single bolt located underneath the seat
  
• New larger airbox to fit the new one-piece tail section
• New air filter carrier with triple mounting pins for more reliability

Instruments / Controls:

• All models have dual compound Renthal grips in grey/orange (smoother and more damage resistant)
• Renthal 608 tapered handlebar (12 mm higher than 2003)
  
• Clutch master cylinder diameter reduced from 10.5 to 9.5 mm (requires less force and offers better clutch control)

Trim / Graphics:

• New decals for the spoiler and airbox cover – seat remains solid black
• New frame guards