If you’ve ever stood in a rice field at harvest time, watching a combine harvester glide through rows of ripe grain, cutting, threshing, and cleaning in one smooth motion, you know it’s not just a machine—it’s the backbone of a season. Over 12 years as a rice combine harvester supplier, I’ve heard the same frustration from farmers again and again: one small, skipped maintenance step during the off-season can turn a critical harvest window into a week of costly repairs. I’ve seen a farmer lose 20 acres of rice because a forgotten clogged cleaning shoe filter caused the machine to stall mid-harvest, right before a forecasted rain that would ruin the entire crop. That’s why today I’m breaking down the exact maintenance steps we walk every customer through before, during, and after harvest—steps that aren’t just “good practice,” but non-negotiable for keeping your harvester running when you need it most. Rice Combine Harvester
First, let’s start with the pre-harvest maintenance, the 2-3 week window before you hit the fields that most farmers either rush through or skip entirely. This isn’t the time to wait for a part to ship; a bad season’s worth of rice relies on getting this right. Let’s start with the undercarriage and track or wheel system, because this is what absorbs 70% of the machine’s daily stress in rice paddies. Rice fields are soft, muddy, and full of sticky, abrasive silt that sticks to every part of the undercarriage. Even a light coating of caked mud on track rollers or sprockets will accelerate wear so badly that you’ll replace them two harvests early. Our first step during pre-harvest is always a full power wash—low pressure on the hydraulic lines, high pressure (about 1,500 PSI, per our technical guidelines) on the frame, rollers, and sprockets. I tell customers to do this in sections, not all at once, to avoid missing small crevices where mud hides. After washing, inspect every track bolt, bushing, and idler wheel for play. For wheeled combines, check tire pressure daily too—rice paddies require lower pressure (12-15 PSI) to avoid sinking, but uneven pressure will cause uneven wheel wear and tear on the transmission. We also grease the entire undercarriage with lithium-based, high-temperature grease rated for heavy loads; rice paddies have temperatures that can reach 100°F by mid-day, so regular grease (not the all-purpose kind) is non-negotiable.
Next, the header, the part of the combine that cuts the rice, is where most farmers make costly mistakes. Rice headers have small, sharp knives and augers that move the cut grain to the threshing unit. After the previous harvest, leftover rice stalks and sap can harden on the knives, making them dull. Dull knives don’t cut cleanly—they tear the rice, leaving behind unripe kernels that will sprout in storage, or even uncut stalks that clog the entire machine. During pre-harvest, we replace or sharpen every knife: use a 60-grit grinding stone for sharpening, then buff with a 120-grit stone to avoid burrs that can damage the auger. I always tell customers to count the knives—for a 20-foot header, that’s 24 knives—and mark any that are bent before sharpening, because a bent knife will throw off the entire cutting alignment. Then, inspect the auger flighting: if you see dents or gaps, weld or replace them immediately. A gap in the auger means cut rice will fall through instead of moving to the thresher, leaving you with waste in the field and lost grain. We also lubricate the header’s adjustment mechanisms—height control, tilt, and reel—with synthetic lubricant that resists water, since rice fields are humid and wet.
Now, the heart of the harvester: the threshing and separating system. This is where the grain is separated from the stalk and chaff, and any issue here means grain loss, which equals lost profit. The threshing cylinder speed is critical for rice—too fast, and you’ll crack the grain, making it unsellable; too slow, and you won’t separate all the grain. Before harvest, adjust the cylinder speed to match the rice variety you’re cutting: long-grain rice needs 800-1,000 RPM, medium-grain 1,000-1,200 RPM. Then, check the concave clearance, the gap between the cylinder and the concave bars that catch the grain. For rice, that gap should be 10-15 mm—too small, and you’ll damage grain; too big, and you’ll leave grain in the stalks. After adjusting, run the cylinder by hand (turn the flywheel, not the engine) to make sure it spins freely, no grinding or catching. I’ve seen a customer skip this step last year and end up with a broken threshing shaft mid-harvest that cost him 3 days and $12,000 in lost harvest. Also, replace the concave bars if they’re worn—if the bars are less than 5 mm thick, they won’t catch grain efficiently, leading to 5-10% more grain loss per acre.
Then, the cleaning system, which often gets overlooked but is equally important. The cleaning shoe uses a fan and sieves to separate clean grain from chaff and stalk debris. Clogged sieves or a faulty fan will leave dirty grain that you can’t sell, or even plug up the entire system. During pre-harvest, remove both the upper and lower sieves and use a stiff brush to remove all rice residue—don’t use compressed air, because that can blow debris into the fan motor and cause overheating. Inspect the fan blades for bent or worn blades; a bent blade will reduce air flow by 20% or more, even if the fan is running at full speed. Adjust the sieve openings too: for wet rice, open the sieves wider (12-15 mm) to let more debris pass, for dry rice, narrow them to 8-10 mm to keep grain in. I always leave a spare set of sieves for customers, because if one breaks mid-harvest, waiting for a replacement can cost you a day of work.
Now, during harvest maintenance, the checks you do every single day, not just once before. I tell our customers to start each day with a 10-minute walkaround, even if the machine ran perfectly the day before. First, check the engine oil and hydraulic fluid level before turning the key—rice harvesters work hard, and a low oil level can seize the engine in minutes. Use the manufacturer-recommended oil (15W-40 for diesel engines, specifically for agricultural use) because standard car oil breaks down under the high load of a combine. I also advise checking the hydraulic fluid filter daily, because rice dust and debris clog it quickly— a clogged hydraulic filter will make the header and reel slow, which can cause you to miss rows of rice. Every evening after harvest, do a quick power wash of the cleaning shoe and thresher, not just the undercarriage—this prevents rice sap from hardening overnight, which will make cleaning harder the next day. One customer of ours tried skipping this daily step last harvest and had to replace a $800 cleaning shoe sieve because it was completely clogged with hardened rice sap.
Another key during-harvest maintenance is replacing filters: engine air filters, fuel filters, and hydraulic filters. Rice fields are full of fine dust and chaff that get sucked into the engine, and a dirty air filter will reduce engine power by 30% and increase fuel consumption by 20%. We tell customers to replace the engine air filter every 8-10 hours of operation, or even every 5 hours if harvesting in very dusty conditions. Don’t just tap the filter to clean it—take it out and blow compressed air from the inside out, not the outside in, to avoid pushing dust deeper into the filter. Fuel filters are even more critical, because dirty fuel can damage the fuel injectors. Rice farmers often store diesel in open tanks during harvest, and condensation or sediment can get into the fuel, so replace the primary fuel filter every 15 hours and the secondary filter every 50 hours.
Now, post-harvest maintenance, the step that most farmers skip and pays for in the next season. After you finish the last acre, don’t just park the combine in the barn and close the door—this is where 30% of long-term wear happens. First, do a full deep clean: power wash every part, including the cab, engine compartment, and all internal components, to remove all rice residue, mud, and sap. Leftover rice stalks will attract rodents, which chew on wires and hoses during the off-season. I had a customer last winter who came back to a combine with $2,500 in damage because mice nested in the engine and chewed through the wiring harness. After cleaning, drain all water from the fuel system—let the engine run until it stalls out from lack of fuel, then fill the tank with fresh, high-quality diesel and add a fuel stabilizer. This prevents algae from growing in the fuel tank during the off-season, which can clog filters and damage injectors when you start back up.
Then, lubricate every single moving part: greasing points, hydraulic cylinders, hinges, and the undercarriage. Even parts that you greased before harvest need a fresh layer, because dust and moisture can wash the old grease away. For the electrical system, check all wires, connections, and lights—rice dust is conductive, and a dirty wire connection can cause a fire during the next harvest, which is a huge risk for expensive farm equipment. Also, store the combine in a covered area, not out in the open, because sun and rain will fade paint, rust metal parts, and crack rubber hoses. If you have to park it outside, cover it with a breathable tarp—do not use plastic, because it traps moisture and causes rust.
Beyond these routine steps, there are two specific maintenance tasks we emphasize for rice combines that other harvesters don’t need. First, the rotary separator (if you have a rotary combine) or the straw walker (if you have a walker-type combine). Rice straw is more fibrous than wheat or corn straw, so it puts extra stress on these parts. For straw walkers, adjust the walker speed to match the rice moisture content—wet rice (above 18% moisture) needs a slower walker speed (400-450 RPM) to avoid plugging, while dry rice (below 15% moisture) can go a bit faster (450-500 RPM). For rotary combines, clean the rotary cage every 20 hours of operation, because rice chaff clogs the gaps between the cage bars, reducing separation efficiency.
The second rice-specific task is checking the grain tank unloading auger. Rice is a finer grain than other crops, so it can pack tightly in the auger, leading to clogging if you don’t maintain it. During pre-harvest, inspect the unloading flighting for wear, and during harvest, run the auger for 10 seconds after you finish unloading, even if the tank is empty, to blow out any remaining rice and prevent it from going stale or hardening. I had a customer who stored his combine with rice stuck in the unloading auger last year, and by spring, the rice had sprouted, creating a sticky mass that took 8 hours to clean out—time he couldn’t spare before planting.
If you’re a new rice farmer, or you’ve been in the business a while and want to cut down on downtime and repair costs, remember: maintenance isn’t a chore, it’s an investment. Every $500 you spend on parts and labor now can save you $5,000 or more in lost harvest and emergency repairs during peak season. That’s why we work closely with every customer to build a customized maintenance schedule based on their specific combine model, acreage, and harvest schedule. If you’re preparing for this year’s rice harvest, or you’re looking for a reliable rice combine harvester that’s built to handle these maintenance needs (with easy access to all parts and simplified servicing), reach out to our team. We’ll walk you through a full pre-harvest inspection, walk you through daily and weekly maintenance steps, and provide you with a spare parts kit tailored to your equipment. Don’t wait until your combine stalls mid-field—prepare now to make this harvest your most profitable yet.
Agricultural Water Pump References:
- American Society of Agricultural and Biological Engineers. (2021). Maintenance Guidelines for Rice Combine Harvesters. ASABE Standard S571.2.
- Food and Agriculture Organization of the United Nations. (2022). Post-Harvest Management of Rice: Equipment Maintenance Practices. FAO Agricultural Engineering Series No. 12.
- International Society of Precision Agriculture. (2023). Performance Optimization for Combine Harvesters in Small-Grain Crops. ISPA Technical Report.
- Kubota Agricultural Machinery. (2020). Rice Combine Harvester Operation and Maintenance Manual. Kubota Corporation.
- John Deere Construction & Forestry. (2021). Combine Harvester Maintenance Best Practices for Rice Production. John Deere Technical Bulletin.
Huzhou Liangyi Agro Machinery Co., Ltd.
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