An all-new 125cc engine makes the 2005 Honda CR125R the most potent two-stroke in its class.

Features & Benefits

New for 2005

– New crankcase intake tract and six-petal reed valve for more efficient air flow and improved drivability.

– New thicker reed plates for better off-idle response.

– Redesigned cylinder and cylinder head for improved power.

– New crankshaft design for improved performance.

– New piston features single keystone piston ring for improved sealing.

– Revised coolant flow for improved engine cooling and increased engine performance.

– Thicker radiator core (from 24mm to 28mm) improves cooling capacity to handle extra power.

– New RC valve changed from electrical to governor actuation for better sealing and improved power characteristics.

– New carb jetting specifications to match new engine characteristics.

– New shift fork shaft, shift forks and shift drum for improved shifting performance.

– ACG rotor weight increased to improve drivability.

– New KYB fork features new fork damper that separates air and oil for reduced contamination and more consistent fork action.

– New front axle placement for improved fork action and turning.

– New swingarm features a dual-axis, double-taper design with a large cast aluminum cross member that is lighter weight and stronger.

– New rear hub is stronger and lighter.

– New Honda Racing-inspired graphics.


– Liquid-cooled two-stroke single-cylinder engine with 54mm x 54.5mm bore and stroke and 8.6:1 compression ratio.

– Nikasil(r)-plated cylinder reduces friction and heat to improve overall performance.
n Piston ring groove is anodized for added durability.

– Air-intake boot is shaped for direct airflow and better low-speed engine performance.

– Foam gasket between airbox and air boot for better sealing and airflow management.

– 38mm Mikuni TMX carburetor with throttle position sensor (TPS).

– Carbon fiber six-petal reed valve with sub reeds is designed for better top-end and low-end power.

– Exhaust port is reshaped to improve top-end and over-rev power delivery.

– RC-style exhaust valve features an NSR road racing-inspired rotary flap design with electronic control that provides a smooth power transition between low- and mid-range engine speeds. Redesigned exhaust valve flap features more overlap to minimize exhaust gas leakage between flap and cylinder.

– Exhaust header is designed to improve low-end and over-rev power delivery. The expansion chamber design enhances the engine’s power output and delivery.

– A four-pole ACG design produces a high-voltage spark throughout the rpm range with low magnetic drag, thus permitting a freer-revving engine.

– A 16-bit processor in the ignition CPU produces immediate data calculation and extremely accurate ignition timing for the digital ignition.

– Eight clutch plates provide significant surface area to handle the engine’s torque. Clutch springs provide a light feel at the lever.

– Dual radiators permit forward engine placement and provide significant cooling capacity.

– Steel water-pump gear and steel kickstarter-shaft collar enhance reliability.

– Primary kickstarting system allows starting in any gear.


– CR(r)125R’s third-generation twin-spar aluminum frame features taller swingarm pivot plates and thinner frame spars to create a narrower overall frame cross-section, and is also lighter than the second-generation frame.

– Semi-double-cradle design features a single, large-diameter tapered downtube. Two rugged box-section rails attach to the base of the downtube and support the engine. A forged aluminum steering head provides a compact and extremely durable mount for the frame spars and engine downtube.

– Front and rear wheels feature HRC(r) works-type lightweight aluminum spoke nipples.

– Front wheel features large-diameter front axle and wide wheel-bearing span for additional rigidity.

– Optional 20-inch front wheel improves cornering traction and rider comfort.

– Rear axle diameter of 25mm and large-diameter bearings provide significant rigidity to withstand torturous track conditions.

– Inverted Kayaba fork features a new twin-chamber design that separates air and oil for reduced contamination and more consistent fork action. Inner surface of fork’s outer tubes is honed to retain a thin coating of lubricating oil to reduce friction with fork bushings.

– Pro-Link(r) single-shock rear suspension system features a fully adjustable Kayaba rear shock with 12.5 inches of travel, separate low-speed (18 positions) and high-speed (two turns) compression damping adjusters, and 30-position rebound damping. The adjusters are located together in a concentric fashion, with a screw inside a nut.

– Compact twin-piston front brake caliper, anodized aluminum brake pistons and lightweight front brake disc reduce unsprung weight for improved turning and handling.

– Lightweight HRC works-type rear brake system.

– Large, 240mm front and rear brake rotors to provide optimum braking control.

Additional Features

– Frame allows sidecovers to have larger air intake openings, with new inner ducts added to significantly increase airflow in low-rpm range.

– Seat follows the shape of the fuel tank, providing a smooth transition to increase rider mobility and comfort.

– “Non-slip” seat cover for increased rider control.

– Wide, cleated stainless steel footpegs are improved for self-cleaning, corrosion resistance, provide excellent grip and fold for extra ground clearance.

– Cleated rear brake pedal, shift lever and folding shift lever tip are made of lightweight aluminum.

– Adjustable front brake lever for optimum control.

– Quick-adjust clutch perch.

– Aluminum Renthal 971 bend handlebar is rubber-mounted to reduce rider fatigue and improve comfort.

– CR handlebar holders provide three different mounting positions: standard CR125R holder provides a 3mm rearward set and can be rotated 180 degrees to position handlebar 6mm forward. Optional holders (CR250R-type) provide neutral position to match rider preference.

– Works-type handlebar grips add to rider comfort.

– Front disc brake cover helps protect rotor and caliper from damage.

– Removable rear subframe allows easy maintenance.

– Dunlop D742 front and D756 rear tires for optimum traction and cornering.

– Washable, two-stage foam air filter for optimal engine protection and easy maintenance.

– Repackable silencer for maximum performance and minimal noise.

– Stainless steel clutch cable for long life.

– Ownership includes one-year complimentary membership in the Honda Rider’s Club of America(tm) (HRCA(r)). Benefits include: discounts, travel benefits, roadside assistance for off-road bike transport vehicle while motorcycle is being transported, one year complimentary subscription to Honda Red Rider(tm) magazine, access to HRCA Clubhouse Web site (, access online to Honda Common Service Manual. For HRCA details, call 1-800-847-HRCA. For dealers only, please call (310) 783-3958.


Model: CR125R

Engine Type: 125cc liquid-cooled single-cylinder two-stroke with RC valve

Bore and Stroke: 54mm x 54.5mm

Compression Ratio: 8.6:1

Induction: Six-petal crankcase reed-valve

Carburetion: 38mm Mikuni TMX with throttle position sensor (TPS)

Ignition: Digital ignition with three-dimensional mapping and electronic advance

Transmission: Close-ratio five-speed

Final Drive: #520 chain; 13T/52T

Front: 46mm inverted Kayaba cartridge fork with 18-position rebound and 20-position compression damping adjustability; 12.0 inches travel
Rear: Pro-Link Kayaba single shock with spring preload, 30-position rebound damping adjustability, and compression damping adjustment separated into low-speed (18 positions) and high-speed (two turns); 12.5 inches travel

Front: Single 240mm disc with twin-piston caliper
Rear: Single 240mm disc

Front: 80/100-21
Rear: 100/90-19

Wheelbase: 57.48 inches

Rake (Caster Angle): 25.48­

Trail: 101.3mm (3.99 inches)

Seat Height: 37.3 inches

Ground Clearance: 13.7 inches

Dry Weight: 197.0 pounds

Fuel Capacity: 2.0 gallons

Color: Red
Consult owner’s manual for optional racing parts.