Old Britts – Converting a Commando to an O-Ring Chain
Download the complete PDF version using the green download button at the top right of this page for detailed Norton Commando O-ring chain conversion procedures and gearing information. This technical article by Fred Eaton explains the complete process of converting a Norton Commando rear drive system from a standard 530 chain to a modern 520 O-ring chain setup for improved durability and reduced maintenance.
The guide explains why standard 530 O-ring chains will not properly fit within the Commando primary case clearance and details the required gearbox sprocket, rear sprocket and chain modifications necessary to complete the conversion safely.
Detailed gearing charts, chain length recommendations and sprocket ratio information are included to help Norton owners select the correct setup for touring, highway riding or performance applications.
The article also covers countershaft clearance checks, sprocket shimming procedures and O-ring chain lubrication recommendations using detailed workshop notes and practical installation guidance.
Contents Include
- 530 to 520 O-ring chain conversion overview
- Gearbox sprocket conversion procedures
- Rear sprocket modification guidance
- 520 chain compatibility information
- Chain width and clearance measurements
- Countershaft sprocket clearance checks
- Sprocket shim installation procedures
- Chain length recommendations
- Gear ratio and speed/RPM charts
- O-ring chain lubrication guidance
- Performance gearing recommendations
- Workshop installation notes
Covered Norton Models
- Norton Commando 750
- Norton Commando 850
- Norton Roadster
- Norton Interstate
- Norton Fastback
- Norton Hi-Rider
- Norton MK3
