Engine Service: Off-Road


This is the way to go if you are serious about winning. Once your suspension is dialed in, and you are pretty well sorted out with your bike, it's time to look at adding some more power. Starts are everything in racing. If you are getting "yanked" on the starts - it's time to step up!

Modern four-stroke engines are remarkable things. These technological marvels are the ultimate in performance and reliability for average riders as well as racers. Large doses of torque and linear power delivery make four-strokes the number one choice for off-road racing. In recent years the weight and reliability of these engines have made great strides and today, four strokes are the obvious choice.

At Yoshimura, we have been building four-stroke racing engines for over 50 years. We understand that your engine is the sum of many parts. We do not simply throw a big cam in, pop up the compression, and create a time bomb. Depending on which stage of engine modification you choose, we build power at self-sustaining, balanced levels.

Stage 1 Components:
Starting @ $675.00

  • De-carbon Combustion Chamber
  • Intake and Exhaust Port and Polish
  • Valve Job and Valve Seat Re-Facing
  • Confirm valve spring tension and condition of associated components prior to assembly
Stage 2 Components:
Starting @ $1700.00

  • All Stage 1 Services Included
  • Yoshimura Professional Assembly Included
  • Yoshimura Camshafts; Machined by Yoshimura Japan from Billet Blanks
  • High-Compression Piston (Compression varies per bike) Call for details.
Stage 3 Components:
Starting @ $2800.00

  • All Stage 2 Services Included
  • Yoshimura Professional Assembly Included
  • Maximum Performance Head Work & Porting
  • Transmission gears are de-burred using Isotropic Surface Finish Process (ISF) to decrease friction and increase power delivery.
Available Engine Kits:
  • 2009-2014 CRF450R
  • 2004-2013 CRF250R
  • 2007-2014 CRF150R
  • 2006-2014 KX450F
  • 2004-2014 KX250F
  • 2005-2014 RM-Z450
  • 2004-2014 RM-Z250
  • 2000-2014 DR-Z400
  • 2006-2009 LT-R450
  • 2006-2014 YZ250F
Additional Services Available:
  • Machine gasket services
  • Mill head to increase compression ratio
  • Inspection and reassembly of top end
  • Complete bottom-end assembly
  • Port and Polish Head
  • ISF Process - Transmission
  • Knife edge and balance crankshaft
  • Complete Race-Spec Engine build for all classes
  • Installation of High Performance Engine Components
    • Camshafts
    • Crankshaft
    • Connecting Rod
    • Piston
    • Valve train components

For Further Information On Yoshimura Engine Services, Please Call Our Sales Department at (800) 634-9166