News Releases 2002

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Power Products
April 22, 2002

Honda Releases the UMK425-The World's Lightest 4-stroke Trimmer

April 22, 2002-Honda Motor Co., Ltd. today announced the release of the new UMK425, the world's lightest*14-stroke trimmer, equipped with the 360°-inclinable GX25 4-stroke engine. The UMK425 is expected go on sale early in the second half of this year at Honda power equipment dealers throughout Japan. (The UT Type goes on sale August 6th.)

Developed in accordance with the concept, "lightweight, light starting, light operating touch," the UMK425 is designed to be the lightest 4-stroke trimmer in the world, delivering both high cutting performance and ease of use.

Thanks to use of the GX25 engine (the world's lightest 4-stroke), a compact gear case, and a unitized fan cover made of a special plastic that is both lightweight and vibration-resistant, dry weight has been reduced to just 4.8kg-on par with a 2-stroke trimmer. Further innovations include an optimized drive gear, specially designed compact, lightweight gear case and weight distribution optimized for maximum operability. In addition, decreased vibration, and lower mechanical noise result in a trimmer that achieves a significant reduction in operator fatigue.

The GX25 also offers superb environmental performance, achieving a top-class*2 ranking under American EPA (Environmental Protection Agency) Phase 2 regulations-the most stringent in the world.

*1 As of April, 2002. Dry-weight measurement, cutting head not installed.
*2 EPA: Class I-A (under 65cc displacement) and Class IV (20cc~50cc displacement)

Another model of the same trimmer, the UMK425H, is expected go on sale early in the second half of this year at designated home centers. This model is equipped with a body designed to home center-series specifications. (The UT Type goes on sale August 6th.)

UMK425 4-stroke trimmer

UMK425 4-stroke trimmer

●Annual projected sales nationwide: 40,000 units
●Manufacturer's suggested retail price (consumption tax not included): UMK425U*
*Price with shoulder strap (shoulder strap price: +¥1,000)

●Other Features of the UMK425

○"Fine Start", for smooth startup and superb acceleration
·Mechanical decompression results in a class-beating starter rope pull weight of just 7kgf (Honda in-house testing) --- so light that anyone can start it with ease.
·A newly developed accelerator pump-equipped carburetor results in excellent acceleration immediately after startup, comparable to that of a 2-stroke.

○Nimble operation
·Weight distribution is optimized for maximum operability. The "Fine Frame" results in a significantly lower shaft swing moment, for reduced operator fatigue.
·The "Fine Grip" features a slimmer handle shape that is easier to grip for people with small hands.
·The "Fine Throttle" employed on the U Type combines the engine speed-adjustment lever with the throttle fixing lever --- just squeeze to fix throttle speed. This results in reduced operator fatigue, even when operating the trimmer for an extended period.
·The "Fine Trigger" employed on the UT and L Types combines a lever that is easy on the fingers even during extended operation with one that allows immediate engine speed adjustment.
·The piston and other moving parts have been lightened for reduced vibration, resulting in less fatigue during hand-held operation.

○Environmental performance
·A Honda e-SPEC engine achieves top-class* ranking in both American EPA (Environmental Protection Agency) Phase 2 regulations and CARB (California Air Resources Board) Tier II regulations --- the most stringent in the world.
*EPA: Class 1-A; CARB: Under 65cc
·Achieves top-of-class fuel economy and oil consumption.
·Oil-immersed timing belt reduces mechanical noise.

·A unified pipe frame and engine and full-cover construction reduce snagging on branches or other objects during operation.
·New Power Red coloring heightens brand identity for Honda power products.


Model Name UMK425
(Designated stores)
(Home centers)
Model Type U UT L UT L
Handle Type U-shaped Loop U-shaped Loop
Throttle Type Fine
Size Length (mm) 1,830 1,875
Width (mm) 610 585 245 630 240
Height (mm) 400 350 240 380 245
Dry Weight (kg) 4.80 4.70 5.25 5.10
Outfitted Weight (kg) 5.60 5.50 6.05 5.90
Engine Model GX25
Engine Type e-SPEC air-cooled 4-stroke single-cylinder OHC
Displacement (cm3) 25
Maximum Output/ Engine Speed
0.81 (1.1)/7,000
Carburetor Diaphragm type
Fuel Type Automotive-grade unleaded gasoline
Fuel Tank Capacity (L) 0.55
Ignition Transistorized magneto
Starter Recoil type (with new decompression system)
Power Transmission Automatic centrifugal clutch
Anti-vibration Measures Unitized clutch housing Rubber mounts
Standard Blade 230 dia. chip saw (36 chip)
Equipment Goggles Included Included Included Included Included
Blade Cover Included Included Included Included Included
Shoulder Strap One/Both One/Both One One One
Tools Included Included Included Included Included
Safety Approval Number To be obtained