General : 727.381.1151   Toll Free : 1.800.875.BRIT(2748)

Norton Commando 850cc Long-Rod Billet Piston Set

Norton Commando 850cc Long-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:

* Required Fields

Questions ?

Answer !

Have a Question about Norton Commando 850cc Long-Rod Billet Piston Set ?

Our customer service has the answer.

Ask Us


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
  • Made with 4032 billet aluminum, high-silicone content for super strength! This alloy'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
  • 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 grooves effeciently hold and disperse increased levels of 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. This results in a cooler running piston and longer piston life
  • Tapered wrist pin inner diameter for rigidity and light weight
  • Race-type SpiroLoc wrist pin clips for added reliability. They will never come out unexpectedly!
  • Fully compatible with Nikasil-plated bores
  • Our piston kits are race-tested world wide!


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

Component weights:

  • piston (based on standard size piston)

MAP9037       850cc  Long Rod      8.5:1 compression  (stock head)      9:1 (.040 decked head)                                                188 grams

MAP9038       850cc  Long Rod     10.5:1 compression  (stock head)     Check clearance with modified or decked heads       220 grams

  • Pin with clips:  60 grams
  • Rings:  17 grams

Compression height:

  • 8:5:1 piston set is 1.006 inches
  • 10.5:1 piston set is 1.128 inches


  • The 8.5:1 pistons work best with premium pump gas
  • The 10.5:1 pistons require racing fuel

Additional Information

Piston Material Billet - 4032
Manufacture MAP Cycle
Additional Information

Additional Information

Piston Material Billet - 4032
Manufacture MAP Cycle

Be the first to review this product

Write Your Own Review

You're reviewing: Norton Commando 850cc Long-Rod Billet Piston Set

Product Question

Product Questions

Question will be displayed after moderation.

No questions yet. Be the first to ask the question!
Shipping Estimation
You can use this section to calculate shipping costs on all available methods for the item on this page, or your entire shopping cart.
  • Yes No

You may also be interested in the following product(s)

Upload images for this product