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Norton Commando 850cc Stock-Rod Billet Piston Set

Norton Commando 850cc Stock-Rod Billet Piston Set

Availability: In stock

Do the job right and buy the very best piston set available for your Norton! More information below:

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Get the very best pistons available for your vintage Norton! Manufactured from 4032 aluminum alloy, they’re the ultimate piston for air-cooled engines!


  • Norton Commando 850cc with long-rod conversion (see MAP7063 stroker rods)


  • Race proven and tested under the harshest conditions
  • High-silicone content for super strength!
  • 4032’s low-expansion properties allows for tighter running clearances which reduces needless engine noise and extends piston life
  • Each billet piston is fully CNC machined using the latest SolidWorks software resulting in the lightest possible weight and even heat distribution throughout
  • This is the lightest, commercially available, vintage, British bike, piston kit on the market
  • Micro-grooved piston skirt for longest life and resistance to scuffing
  • Second ring-land accumulator groove helps prevent the unloading of the top ring from trapped blow-by gases
  • Updated wrist-pin oiling with four pressure-fed location holes. This increases oil volume to the pin and limits heat buildup in the small end of the rod and wrist pin
  • Dual clocked pin bore grooving holds and disperses the oil around the wrist pin
  • Race-proven ring pack built by the highest quality, performance ring manufacturer (see ring specs below). Modern metric sizing for the least amount of friction with the best heat transfer for cooler running piston and longer piston life
  • Tapered wrist-pin inner diameter for rigidity and lightweight
  • Race-type SpiroLoc wrist pin clips for added reliability - they will not ever come out!
  • Our piston kits are race-tested world wide!
  • Compatible with Nikasil plated bores


  • Two race-proven, billet alloy pistons
  • Two sets of high-performance piston rings
  • Two lightweight wrist pins
  • Four SpiroLoc wrist pin clips
  • Full installation instructions

Piston Rings:

  • 1.0mm Nitrited stainless steel barrel-face top ring
  • 1.2mm Ferrox iron “Napier-style” second ring
  • 2.8mm Nitrited stainless steel rails with expanded (three-piece design) oil ring

Component weights:

piston: based on standard size, 77mm piston - larger pistons may weigh slightly more

MAP9035A/7700   850cc  Stock Rod    8.5:1 compression  (stock head)     9:1 (.040 decked head)   234 grams (bare), with pin, clips and rings: 312 grams

Note: Pin location for this piston is the same as stock relative to stock crank

Additional Information

Piston Material Billet - 4032
Manufacture MAP Cycle
Additional Information

Additional Information

Piston Material Billet - 4032
Manufacture MAP Cycle

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