S-734 Lever Action Grease Gun

Frequently Asked Questions: S-734 Japanese Style Jiabara Lever Action Grease Gun

What is a Jiabara grease cartridge and how is it different from a standard 14 oz. cartridge?

A Jiabara cartridge is a sealed bellows-style grease cartridge whose body collapses as grease is dispensed, unlike a standard tube cartridge that relies on a follower plate pressing through a rigid tube. The Jiabara format is the stock grease supply format across Japanese industrial markets and much of Asia. The bellows collapse means grease is extracted more completely from the cartridge (nearly 100 percent utilisation versus 85-90 percent on standard tubes), and air pockets cannot form between the follower and the grease column because the bellows walls stay in contact with the grease at all times. Cartridges are sold by Japanese grease brands and industrial lubricant suppliers through industrial supply channels in Japan, Taiwan, Korea, and other Asian markets.

Why is the S-734 called a Japanese style grease gun?

The "Japanese style" designation refers to two mechanism choices specific to the Japanese industrial lubrication market: the threaded port on the head that accepts Jiabara bellows cartridges directly, and the chain-style follower handle that flexes with the bellows cartridge as it collapses. Both features are the dominant design in Japan and among Japanese manufacturer service tool specifications, distinct from the standard-barrel tube-cartridge design that dominates worldwide markets and the wide-barrel format used in Australia and New Zealand. The S-734 matches the Japanese-standard architecture so that Japanese and Asian buyers can pair it with their stocked cartridge supply and service their equipment consistent with Japanese OEM service expectations.

Can I use a standard 14 oz. (400 g) cartridge in the S-734?

No. The S-734 has a 59.7 mm barrel sized for the Jiabara cartridge geometry and a threaded port on the head designed for the Jiabara thread profile, neither of which is compatible with standard 14 oz. tube cartridges. Attempting to use a standard tube cartridge in the S-734 results in a cartridge that cannot seat properly and cartridge-head interface that does not seal. For markets stocking 14 oz. tube cartridges, use the standard-barrel STAR range (S-707, S-706, S-708, etc.), which has the 57.15 mm barrel correctly sized for the worldwide tube cartridge format.

How does the chain-style follower handle differ from a rigid plunger rod?

A rigid plunger rod pushes through a follower plate to compress grease inside a tube cartridge or bulk reservoir; a chain-style follower handle uses a flexible chain link to maintain consistent pressure on a bellows cartridge as the cartridge collapses. On a tube cartridge, the follower plate stays in contact with the grease column as the plunger rod advances. On a Jiabara bellows cartridge there is no separate follower plate: the cartridge body itself folds in on itself as grease dispenses. A rigid plunger rod cannot follow this collapsing geometry reliably, while a chain flexes with the folding bellows and keeps steady pressure. The chain follower is also the mechanism that enables nearly complete grease utilisation, because it stays engaged with the cartridge right to the last fold of the bellows.

What is the 8,000 PSI pressure rating of the S-734 suited for?

8,000 PSI (550 bar) is a mid-tier pressure rating matched to general industrial lubrication, machine-tool bearings, automotive chassis service, and light agricultural equipment where clean grease delivery matters more than maximum pressure capability. For fittings that crust from extended outdoor exposure between services (outdoor-stored construction equipment, mining haul trucks), 8,000 PSI may not reliably clear the crust and the 12,000 PSI heavy-duty range is the correct pick. For clean automotive, machine-tool, and workshop service where fittings are well-maintained on regular schedules, 8,000 PSI is above the 6,000 PSI medium-duty tier and provides adequate safety margin without over-specification.

Is 8,000 PSI safe for bearing seals during service?

Yes. Bearing seals typically fail at internal grease-cavity pressures of 500 to 1,500 PSI, far below the 8,000 PSI maximum the S-734 can develop at a fully blocked fitting. Actual pressure reaching the bearing seal depends on the fitting's flow restriction: a clean zerk on a healthy bearing passes grease at low pressure. The 8,000 PSI specification is the maximum the pump can build when the coupler is completely blocked, not the steady-state pressure reaching the bearing. To prevent over-greasing, stop pumping the moment fresh grease appears at the bearing seal or the lever resistance sharply increases.

Can the 8,000 PSI of the S-734 cause a grease injection injury?

Yes. Grease injection injuries from 8,000 PSI grease guns are documented in emergency medicine and require immediate surgical treatment. A pinhole in the hose or an unseated coupler can drive grease through intact skin at 8,000 PSI. The initial wound looks like a tiny puncture and often does not hurt much initially; grease then migrates along tissue planes and causes chemical damage that becomes visible as swelling, colour change, and infection over 24-72 hours. Go to an emergency department immediately for any suspected injection injury, brief the staff it is a high-pressure grease injection (not a simple puncture), and do not wait for pain to develop. Untreated grease injections can progress to tissue necrosis and amputation regardless of whether the gun is a medium, mid-tier, or heavy-duty pressure class.

Why does the S-734 have 3-way loading instead of 4-way?

The chain-style follower mechanism is optimised for Jiabara bellows cartridge loading and for direct grease-column pressure from the follower spring during bulk and suction loading. Filler pump loading requires a pressure-fed feed inlet that conflicts with the chain-follower geometry, so it is not supported on the S-734. For operators who specifically need filler-pump loading (typically high-volume mining or fleet depots where multiple guns reload rapidly from a shared filler pump), the 4-way standard-barrel lever guns from STAR support this format. For Japanese and Asian industrial lubrication use cases where Jiabara cartridges dominate and filler-pump loading is rare, 3-way loading covers the realistic service formats without the mechanism complexity of adding a filler-pump inlet.

Where can I buy Jiabara bellows cartridges outside of Japan?

Jiabara cartridges are widely stocked across Taiwan, Korea, Hong Kong, Singapore, and other Asian industrial markets through Japanese grease-brand distribution chains and Asian industrial supply distributors. In Europe, North America, and other non-Asian markets, Jiabara cartridges are sometimes available through specialty-tool importers and Japanese-OEM service parts suppliers, but the supply is less consistent than in the Jiabara primary markets. If you're buying the S-734 for a non-Asian market specifically for Japanese-OEM equipment service, confirm local Jiabara cartridge availability before committing; if cartridges are not readily stocked locally, the bulk-fill and suction-fill modes of the S-734 can serve as backup formats but the gun's primary use case assumes Jiabara cartridge availability.

How do I load a Jiabara cartridge into the S-734?

Remove the cap from the fresh Jiabara cartridge, position the cartridge at the threaded port on the head, and screw it home until firmly seated. The barrel does not need to be unscrewed and the chain follower does not need to be retracted. Once the cartridge is seated, pull the lever once or twice: grease should flow on the first or second pump because the bellows cartridge has no air pockets. If priming fails after 3-4 pumps, check that the cartridge is fully threaded home against the head gasket (not just finger-tight), and confirm the cartridge is fresh (not an expired stock item where the bellows has set). The cartridge-change workflow typically takes 15 seconds, significantly faster than the standard-tube cartridge change that requires barrel disassembly.

Can the S-734 be bulk-filled without using a Jiabara cartridge?

Yes. The S-734 supports bulk loading of the 600 cc reservoir as a backup format when Jiabara cartridges are not immediately available or when bulk-fill economics favour non-cartridge supply. To bulk-fill: retract and lock the chain follower, unscrew the barrel, dip the barrel mouth into a 5 kg or 15 kg grease pail, pack grease firmly against the sidewalls with a scoop to fill the 600 cc reservoir, and reassemble. Bulk-fill priming takes 3-5 pump strokes (longer than Jiabara cartridge priming which is 1-2 strokes) because there may be air pockets in the bulk-packed grease column. For most Japanese and Asian markets, Jiabara cartridges are the primary loading mode and bulk-fill is used only occasionally.

Is the S-734 suitable for tractors and heavy equipment service?

For clean, regularly-maintained agricultural and light construction equipment: yes, 8,000 PSI is adequate. For outdoor-exposed heavy equipment with crusted fittings: no, the 12,000 PSI heavy-duty range is the correct pick. The S-734 is sized for machine-tool, automotive, and light-industrial service where fittings are cleaner than outdoor heavy-equipment zerks. For Asian broadacre farms, compact tractors, and light construction equipment on regular service schedules, the 8,000 PSI is above adequate. For mining equipment, large excavators, and outdoor-stored heavy machinery, step up to the heavy-duty range. The specialty-cartridge family as a whole (S-733, S-734, S-735, S-739) is positioned at the mid-tier pressure range; heavy-duty Asian-market service typically uses the standard-barrel heavy-duty lever guns shipped with imported 14 oz. cartridges.

Why do bellows cartridges prevent the air-pocket priming problem?

Standard tube cartridges use a follower plate that pushes through a rigid tube to compress the grease column; if the follower plate loses contact with the grease column (common after partial fills, long storage, or cold-weather service), air pockets form and cause priming failures. Bellows cartridges have no separate follower plate: the cartridge body itself collapses as grease dispenses, so there's never a gap between the follower and the grease. This is the mechanical difference that makes Jiabara-style loading more reliable than tube-cartridge loading for priming consistency. The bellows also serves as a primary seal against contamination: the cartridge is sealed at manufacture and stays sealed until the operator connects it to the S-734 threaded port.

What PPE should I wear when using the 8,000 PSI S-734?

Mandatory: wraparound safety glasses (ANSI Z87.1+ impact-rated), nitrile chemical-resistant gloves, long sleeves, and closed-toe shoes at minimum. Safety rules: never point the coupler or flex hose at any body part, keep the non-lever hand behind the coupler head during pumping, inspect the hose and coupler before each use for visible damage, never test grease flow by pressing the coupler against skin or fabric. At 8,000 PSI a pinhole in the hose or unseated coupler can drive grease through intact skin and cause injection injury. PPE requirements are pressure-tier-based not cartridge-type-based: the bellows cartridge format does not change what PPE is needed versus a tube cartridge gun at the same pressure rating.

Can the S-734 be rebuilt with standard STAR spare parts?

Partially. The chain-follower assembly and the threaded port components are specific to the Japanese-style mechanism; the head seals, plunger-rod seal, non-return valve, coupler, hose, and steel extension are common with other STAR lever guns. Rebuild kits for the S-734 are supplied from the STAR spare parts catalogue including the Jiabara-specific chain follower components. Wear-part lifespan at regular industrial service: chain follower links 3-5 years, seals and O-rings 3-5 years, coupler and hose 3-4 years. For Japanese and Asian distributors stocking S-734, carrying the chain-follower rebuild kit as a separate SKU alongside the general STAR seal kits covers all rebuild scenarios.

Is the S-734 available for OEM and private-label orders to Japanese distributors?

Yes. OEM and private-label manufacture is available on the S-734 for Japanese, Taiwanese, Korean, and Asian distributors including custom branding, packaging design for Japanese/Asian retail or industrial-supply format, and kit configuration per agreement. MOQ depends on customisation level: product-level rebranding (logo and packaging only) has a lower MOQ than full thread or kit-spec customisation. Shipping is sea freight to Yokohama, Kobe, Osaka, Busan, Keelung, Kaohsiung, Hong Kong, Singapore, and other major Asian ports. Mixed-container consolidation with other STAR products (pistol grip guns, standard lever guns, accessories) is possible to hit MOQ thresholds economically. Contact the STAR export team for Japanese/Asian distributor pricing, lead times, and packaging specifications.