Description
Overview:
The Flywheel Fixing Nut is a genuine JAP part for securing the flywheel on vintage JAP engines, including JAP 4/3 and JAP 5. Made from robust steel with a hex profile for standard spanner fitting, it clamps the flywheel firmly to the crankshaft to maintain correct alignment and dependable operation. As unused old stock, the nut is original equipment and may show minor tarnishing consistent with age, which does not affect function. It is suitable for restorations, servicing, and routine maintenance of classic JAP power units often found on older construction, horticultural, and agricultural machinery. This OEM nut helps prevent flywheel movement that can cause poor running, ensuring reliable starting and consistent timing across well-maintained engines.
Key Features:
- Genuine JAP part for correct fit and function on JAP 4/3 and JAP 5 engines
- Durable steel construction for long service life
- Hexagonal form for easy tightening with a standard spanner
- Unused vintage stock; cosmetic tarnish may be present but performance is unaffected
- Helps maintain correct flywheel seating and ignition timing
- Direct replacement for OEM No. 12859 to simplify sourcing
- Suitable for engine rebuilds, repairs, and preventative maintenance
- Period-correct component to keep restorations authentic
Typical Applications:
Used to secure the flywheel after engine rebuilds, magneto or key inspections, or when replacing a damaged or rounded original nut. Common on vintage JAP-powered equipment such as mixers, pumps, generators, cultivators, and mowers, where a stable flywheel connection is essential for smooth running and dependable starting.
Also known as:
Flywheel nut, flywheel retaining nut, crankshaft nut, engine fixing nut, flywheel securing nut, JAP flywheel fastener, OEM 12859 nut.
Fits Models:
JAP 3, JAP 4, JAP 5
Alternate Part Numbers:
12859
