Description
Overview:
This Spring for Inlet/Exhaust Valve is a genuine JAP component for JAP 3 and JAP 4 engines, supplied to restore correct valve operation on vintage machinery. Made from hardened spring steel with a dark protective finish, it delivers the controlled tension needed to close the inlet and exhaust valves cleanly, supporting stable idle, good compression, and reliable running. The spring measures 41 mm (1.61 inches) in free length with a 23.5 mm (0.93 inches) outer diameter and 18 mm (0.71 inches) inner diameter, matching original factory dimensions for proper fit and clearance. Supplied as unused old stock, it is ideal for engine overhauls and period-correct restorations where authenticity and dependable performance matter.
Key Features:
- Genuine JAP part for correct fit and performance (MPN 7720)
- Hardened spring steel construction for durability and consistent valve control
- Correct dimensions: length 41 mm (1.61 in), O/D 23.5 mm (0.93 in), I/D 18 mm (0.71 in)
- Suitable for both inlet and exhaust positions on JAP 3 and JAP 4 engines
- Helps maintain valve seating, timing accuracy, and smooth running at working revs
- Direct replacement for worn or weakened originals; no modification to standard hardware
- Resistant to fatigue and set when used within original engine specifications
- Unused old stock; may show light storage marks without affecting function
- Supports reliable starting, efficient combustion, and reduced valve float
Typical Applications:
Used during cylinder head rebuilds, routine maintenance, or full restorations of JAP 3 and JAP 4 engines found in vintage stationary engines and small plant. Suitable for replacing tired or fractured valve springs to restore correct valve operation on heritage construction, agricultural, and garden machinery powered by JAP single-cylinder engines.
Also known as:
Valve return spring, inlet valve spring, exhaust valve spring, JAP 7720 spring, engine valve coil spring, J.A.P. valve spring, vintage JAP valve return spring.
Fits Models:
JAP 3, JAP 4
Alternate Part Numbers:
7720
Product Specifications
| L&S Part No. | 7720 |
|---|---|
| Part Type | Genuine Part |
| Manufacturer | JAP |
| OEM No. | 7720 |
| Unit of Sale | 1 |
| Applications | JAP 3, JAP 4, JAP3, JAP4 |
| Machine Type | Engines |
| Fits Brands | JAP |
| Fits Models | JAP 4, 3 |
