Kubota PRO688Q Multi-Crop Combine Harvester – Complete Guide

Kubota PRO688Q Multi-Crop Combine Harvester: Powerful Harvesting for Rice and Other Crops

The Kubota PRO688Q is a tracked, full-feed combine harvester designed for efficient harvesting and threshing operations in field conditions where mobility, traction and crop handling are important.

The PRO688Q platform is associated with rice and rapeseed harvesting, while published specifications for different versions also describe configurations intended for crops such as wheat. Kubota documentation has specifically identified the PRO688Q as a conventional-type combine for rice and rapeseed in China.

Its combination of a crawler-track undercarriage, turbocharged diesel engine, full-feed harvesting system and longitudinal axial-flow threshing system makes it an interesting machine for farmers, contractors and agricultural machinery businesses looking for a compact tracked combine.

Key Highlights of Kubota PRO688Q

Machine type: Full-feed tracked combine harvester
Brand: Kubota
Model: PRO688Q
Drive system: Rubber crawler tracks
Engine: 4-cylinder turbocharged diesel
Rated power: Around 49.2 kW in documented variants
Engine speed: Around 2,700 rpm
Cutting width: Approximately 2.0 metres, depending on variant
Threshing: Longitudinal axial-flow system
Threshing drum: Approximately 620 × 1,790 mm on documented versions
Grain tank: Approximately 1,000 litres on large-grain-tank versions
Transmission: Mechanical transmission with HST/hydrostatic variable-speed drive
Minimum ground clearance: Around 259–275 mm, depending on version
Track width: Up to approximately 450 mm on certain versions
Main crop applications: Rice and other suitable cereal/field crops depending on header and configuration

Published specifications show that the PRO688Q family has more than one configuration, so buyers should verify the exact model plate and specification before purchasing a used machine.

1. Engine and Power

One of the important features of the PRO688Q is its four-cylinder, water-cooled, turbocharged diesel engine.

A documented PRO688Q variant uses a Kubota V2403-M-DI-T-ES04 engine with:

4 cylinders
Vertical configuration
Water cooling
Turbocharging
Displacement: approximately 2.434 litres
Rated power: 49.2 kW
Rated speed: 2,700 rpm

These figures are from a published 4LZY-1.8(PRO688Q) specification and should not automatically be applied to every PRO688Q configuration.

The turbocharged engine is designed to provide the power required for harvesting, feeding and threshing while maintaining useful performance under demanding field conditions.

2. Crawler Track System

One of the biggest advantages of the Kubota PRO688Q is its rubber crawler-track system.

Compared with a conventional wheeled agricultural machine, tracks provide a larger contact area with the soil. This can be particularly useful in rice-growing areas where fields may be soft or wet.

A documented version uses:

90 × 51 × 400 mm tracks, while another large-grain-tank configuration uses approximately 90 × 51 × 450 mm tracks.

The published ground-pressure figures are approximately 20.6 kPa and 18.7 kPa, depending on configuration.

Why crawler tracks matter

Crawler tracks can help provide:

Better traction
Improved stability
Reduced risk of wheel spin
Better mobility in soft agricultural fields
More effective operation in wet rice-field conditions

3. Cutting and Header System

The PRO688Q uses a front harvesting header to cut and feed standing crops into the machine.

A documented configuration has approximately a 2,000 mm cutting width. Another PRO688Q specification lists approximately 2,020 mm.

The harvesting system is designed to pick up the crop and deliver it continuously into the feeding and threshing system.

This makes the machine suitable for harvesting operations where farmers want to combine several field operations into one pass.

4. Full-Feed Harvesting System

The PRO688Q is a full-feed combine harvester.

The crop enters the machine through the header and feeding mechanism before being transferred into the threshing system.

One published PRO688Q configuration lists a feeding capacity of approximately 2.5 kg/second.

The actual field capacity will depend on:

Crop variety
Crop yield
Moisture
Lodging
Field condition
Operator skill
Header settings
Machine configuration

Therefore, catalogue capacity should not be interpreted as a guaranteed field production rate.

5. Longitudinal Axial-Flow Threshing

One of the major engineering features of the PRO688Q is its longitudinal axial-flow threshing system.

A documented version uses a threshing drum measuring approximately:

620 mm diameter × 1,790 mm length

with a drum speed of approximately 560 rpm.

The long axial-flow design allows the harvested crop to move through the threshing system while threshing and separation take place.

This design can provide several advantages:

Continuous crop processing
Effective threshing
Good separation
Compact machine layout
Reduced crop-processing complexity

Kubota's published descriptions also highlight the use of an adjustable guide plate to adapt the crop flow according to field and crop conditions.

6. Grain Collection

The PRO688Q is available in configurations with different grain-handling arrangements.

One documented configuration has a 420-litre collection capacity, while the larger-grain-tank version has approximately a 1,000-litre grain capacity.

The larger grain-tank configuration is especially useful when operators want to reduce the frequency of unloading during harvesting.

Some versions are equipped with an unloading auger arrangement, with published specifications giving different unloading heights and extension ranges depending on whether the system is manually or hydraulically operated.

7. Hydrostatic Transmission

The PRO688Q uses a transmission system incorporating HST/hydrostatic variable-speed control.

A published specification lists:

Forward: continuously variable
Reverse: continuously variable
Sub-transmission: 3 ranges
Theoretical travel speeds: approximately 0–3.49 km/h, 0–4.93 km/h and up to 6.66 km/h, depending on range.

Hydrostatic speed control is particularly useful during harvesting because the operator can adjust forward speed according to crop density and field conditions.

8. Performance in Rice Fields

Rice harvesting is one of the key applications associated with the PRO688Q.

The crawler system is particularly relevant to rice farming because harvesting often takes place in fields where soil conditions can be challenging.

The machine can combine several operations:

Cutting → Feeding → Threshing → Separation → Grain Collection

This reduces the need for separate harvesting and threshing operations.

9. Other Crop Applications

The PRO688Q name is also associated with multi-crop harvesting configurations.

Depending on the exact machine, header and configuration, applications can include:

Rice
Wheat
Rapeseed/canola
Other compatible cereal or field crops

However, crop compatibility should always be confirmed for the particular PRO688Q version rather than assuming every machine is configured for every crop.

Kubota's own historical documentation specifically identifies the PRO688Q for rice and rapeseed, while other published PRO688Q configurations describe rice, wheat and rapeseed applications.

10. Working Capacity

A published PRO688Q specification lists a theoretical field productivity of approximately:

0.2–0.4 hectares/hour

for a particular configuration and crop/field condition. Another version gives approximately 0.2–0.53 ha/hour under specified dry-field conditions.

Actual productivity can vary significantly.

For example:

Higher productivity

Dry field
Standing crop
Good crop uniformity
Proper machine adjustment
Experienced operator

Lower productivity

Wet field
Heavy crop
Lodged crop
High moisture
Weeds
Poor field preparation

11. PRO688Q Dimensions and Weight

Published specifications vary by version.

For example, one PRO688Q configuration lists:

Specification	Approximate figure
Transport length	5,150 mm
Working length	Up to 5,300 mm
Transport width	2,340 mm
Working width	Up to 2,810 mm
Height	Approximately 2,720–2,815 mm
Operating weight	Approximately 2,930–3,005 kg
Cutting width	2,000 mm
Ground clearance	275 mm

Another PRO688Q configuration is listed around 4,950–4,990 mm long, 2,440–2,750 mm wide and approximately 2,760–2,800 mm high.

Important: These differences demonstrate why the exact model/version should be checked before importing or purchasing a PRO688Q.

12. Advantages of Kubota PRO688Q

1. Crawler drive

The rubber crawler system is well suited to agricultural fields where traction is important.

2. Compact design

The machine combines cutting, feeding, threshing and grain collection into a relatively compact package.

3. Axial-flow threshing

The longitudinal axial-flow system provides continuous crop processing.

4. Turbocharged diesel engine

The turbocharged four-cylinder engine provides useful power for harvesting and threshing operations.

5. Hydrostatic speed control

HST allows the operator to adjust harvesting speed according to crop conditions.

6. Rice-field suitability

The tracked configuration makes the machine particularly attractive for rice harvesting operations.

13. Important Things to Check When Buying a Used PRO688Q

If you are considering importing or purchasing a used Kubota PRO688Q, don't look only at the engine hours.

Check:

Engine

Engine starting condition
Blow-by
Oil pressure
Coolant condition
Turbocharger
Injector condition
Engine smoke

Crawler system

Track condition
Track tension
Sprockets
Rollers
Idlers
Hydraulic drive

Header

Cutter bar
Reel
Auger
Bearings
Belts
Chain
Hydraulic cylinders

Threshing system

Threshing drum
Concave
Guide plates
Bearings
Belts
Sprockets

Grain system

Grain tank
Auger
Unloading system
Cleaning fan
Sieves

Electrical system

Battery
Alternator
Starter
Sensors
Meter panel
Wiring

Hydraulic system

Hydraulic pump
Hydraulic hoses
Cylinders
HST system
Oil leakage

14. Why the PRO688Q Is Interesting for the Indian Market

For areas where rice farming is widespread, a tracked combine can be attractive because the machine is designed around the requirements of harvesting in agricultural fields where ground conditions can be difficult.

For Indian buyers, however, the most important consideration is not simply the Kubota name. Buyers should verify:

Exact PRO688Q variant
Year of manufacture
Engine number
Chassis number
Operating hours
Track condition
Header condition
Availability of spare parts
Machine documentation
Import requirements
Local service capability

This is especially important when purchasing a used machine from Japan or China.

15. Kubota PRO688Q Specifications at a Glance

Feature	PRO688Q
Machine	Full-feed combine harvester
Drive	Rubber crawler
Engine	4-cylinder turbocharged diesel
Example engine	V2403-M-DI-T-ES04
Displacement	2.434 L
Rated power	49.2 kW
Rated speed	2,700 rpm
Header width	Approx. 2,000 mm
Feeding capacity	Approx. 2.5 kg/s on documented variant
Threshing	Longitudinal axial flow
Drum size	Approx. 620 × 1,790 mm
Drum speed	Approx. 560 rpm
Grain tank	Up to approx. 1,000 L on documented version
Transmission	HST / variable-speed
Ground clearance	Approx. 259–275 mm
Tracks	Up to approx. 450 mm wide
Main application	Rice and other suitable crops
Production rate	Approx. 0.2–0.4 ha/h on a documented configuration

Specifications are variant-dependent and should be confirmed against the machine's identification plate and original manual before purchase.

Final Verdict

The Kubota PRO688Q is a compact tracked combine harvester designed around efficient crop cutting, feeding, threshing, separation and grain collection. Its crawler undercarriage, turbocharged diesel engine, HST drive and axial-flow threshing system make it particularly interesting for rice harvesting and other compatible crops.

For farmers and agricultural machinery traders, the PRO688Q can be an attractive option where traction, compact dimensions and efficient harvesting are more important than the very high capacity of a large modern combine.

Kubota PRO688Q Multi-Crop Combine Harvester – Specifications, Features & Performance