For the most demanding raking operations

GA 4121 GM and GA 4321 GM single rotor rakes have MASTER DRIVE gearboxes, which are extremely reliable during intensive operations. The working widths of these machines are 4.10 m and 4.20 m respectively.


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These single rotor rakes are as dependable as the larger models. Their MASTER DRIVE gearboxes are made to cope with the most intensive operations. In addition, they produce an impressive work output with their large working widths and the pivoting headstock, making easily maneuverable.

Your Benefits

As dependable as a larger model

MASTER DRIVE gearboxes

The rotor drive system is under a lot of strain during intensive raking operations. That’s why KUHN developed a totally enclosed gearbox with the mechanical parts protected to reduce wear.
The MASTER DRIVE gearbox is renowned for its dependable design and exceptional longevity, even when used intensively.
It includes a double reduction system with a bevel gear and a cylindrical gear. Bevel-reduction tolerances are tightly controlled making the system extremely reliable and robust, even in difficult conditions.
Gearbox wear is greatly reduced and no maintenance is required. The double reduction system makes it possible to include larger cylindrical gears with more teeth for better power transmission.

Tines are made from heat treated steel

The tines rake the crop gently, even when it is heavy and dense. They are made of heat treated steel so their service life is optimised and resistance to fatigue is increased. The “floating” tine attachment, featuring three large-diameter coils, also reduces the risk of wear. Tine height is tightly controlled to preserve both the stubble and the crop.

Great raking for clean forage, free of impurities

Optimum swath formation from the double-curved arms

The homogeneous quality and the volume of swaths are necessairy for faster drying and easy pick-up by balers.
The tine arms on GA rakes are in a hyper-tangential position. This means that they reach a 90° angle very late. With the tines’ sharp-angled cam, tine clearance is quick, later and requires little rotational effort to produce regular, fluffy and straight swaths. Raking is of high quality even at fast speeds because the forage is not pushed past the swath.
The advantages of double-curved arms:

  • They reduce the distance between tine passes. Forage loss is reduced, even at higher speeds.
  • The main weight is at the centre of the tine arm. This increases service life as it is not subject to pressure during rotation and the guide rollers are less subjected to stress.

Swath curtain

The swath curtain mounted on the frame, is easily adjusted by a handle. It can also be set from the tractor cab via an optional hydraulic cylinder. When extended outwards, the screen automatically moves to the rear, when retracted inwards, it moves to the front. This is very practical as it is always correctly placed in relation to the crop flow.

Wheels are positioned to prevent crop contamination

The wheels are positioned extremely close to the rotor for improved ground contour following and to prevent the introduction of impurities in the forage.

Stable on slopes

Flexible pivoting headstock

GA 4121 and GA 4321 models are available with a pivoting headstock, which makes them as effective as a trailed machine.
At nearly 50 °, this coupling head offers the widest swivel angle on the market. Working on bends does not alter the raking quality or the shape of swaths so the baler has an easier job around corners

Work quickly and efficiently with bogie axles

To optimise ground speed, raking quality, preserve ground cover and protect the machine against wear and tear from uneven terrain, GA 4121 and GA 4321 models have another important feature: The bogie axle with four staggered wheels adapts to ground contours and keeps the machine stable during higher working speeds.

Headstock dampeners

These single rotor models are equipped with one or more headstock dampeners to improve stability on slopes (standard on GA 4321 models, optional on GA 4121).
When lifting the rotor, the dampener automatically and smoothly centres the headstock behind the tractor


Technical characteristics

ModelsGA 4121 GMGA 4321 GM
Working width (m/ft)4.10/13'5" (right windrow)4.20/13'9" (right windrow)
Average windrow width (m/ft)Approx 1.30/4'3"Approx 1.40/4'7" according to setting
Raking deflectorWindrow curtainWindrow curtain
Width (m) - tine arms removed/ in place1.75/5'7"1.95/6'4"
Unfolding and folding of guardsManualManual
Windrow curtain opening adjustmentManualManual as standard - hydraulic as an option
Number of rotors / Rotor diameter (m/ft)1/3.20 - 10'5"1/3.40 - 11'1"
Number of tine arms per rotor / Number of tines per arm10/412/4
Tine armsRemovableRemovable
GearboxEnclosed-Double Stage-MASTER DRIVEEnclosed-Double Stage-MASTER DRIVE
Bogie axle--
Height adjustmentBy scaleBy scale
Tyres under rotor16x6.50 - 816x6.50 - 8
Primary PTO shaft--
Linkage3-point-Cat. 1 and 23-point - Cat 2
Headstock suspension-1 as standard - 2 as option
Min. PTO power requirement approx. (kW) 2222
Min. PTO power requirement approx. (hp) 3030
Necessary tractor hydraulic equipment--
Lighting and signaling--
Approx. weight (kg/lbs)540/1190702/1547