Norton 850 Commando – Stage One High Performance Modifications
Download the complete PDF version using the green download button at the top right of this page for the original Norton service release covering Stage One high performance modifications for the 850 Model Commando. This factory technical document explains the parts changes, machining work, setup details and tuning specifications required to convert a standard road specification 850 Commando toward a higher performance sports condition.
The service release covers replacement of the standard camshaft with the 063536 “SS” camshaft, piston crown modification, cylinder head machining to increase compression ratio, new Amal velocity stacks for the carburettors and pushrod changes needed to maintain correct rocker geometry after the cylinder head has been altered. It also includes technical drawings for piston crown work, cylinder head combustion chamber modifications and pushrod dimensions.
Additional tuning information is provided for ignition timing, contact breaker advance, valve clearance, exhaust setup and carburettor jetting. The document also includes a Norton service tools section illustrating specialist workshop tools such as clutch compression tools, slide hammers, seal guides, sprocket lock tools, timing pinion extractors, valve guide tools, exhaust lockring spanners, Isolastic assembly tools and strap wrenches.
Contents Include
- 850 Commando Stage One performance conversion overview
- SS camshaft replacement specification
- Piston crown machining requirements
- Cylinder head modification for higher compression
- Pushrod shortening and rocker geometry notes
- Ignition timing and valve clearance settings
- Carburettor and exhaust recommendations
- Factory technical data for the high performance setup
- Norton specialist service tools catalogue
- Illustrated workshop tool applications and part references
