Colorado Norton Works is open for business and fulfilling orders. It may take me a couple of extra days to get things shipped but we have a daily UPS service and will go to our local post office once a week. I sincerely hope everyone in our Norton community is staying healthy. You can do worse than being stuck in your garage for a few weeks working on your Commando. If there is anything I can do to help with your project, it is best to contact me via email at Thanks Matt

cNw Complete Rebuild / Engine & Transmission details

Horsepower sells, but a “streetable” and dependable custom motorcycle it does not necessarily make. The purpose of Colorado Norton Works’ motorcycle engine rebuilds is to get Norton Commandos on the road and keep them there.

Improvements to head flow and more aggressive cam profiles are certainly possible, but too often improvement in one area can only be capitalized upon by improvement in additional areas. To arrive at a well-balanced engine, the “domino effect” of these improvements usually drives expense to an excessive level. However, at cNw, we carefully plan and apply all steps in the motorcycle engine rebuild process. Through this attention to detail, we deliver a machine that is balanced from the very core and up.

With the cNw Norton Commando motorcycle engine rebuild, our basically stock engines are smooth and precise, capitalizing on the low end and mid range torque that these engines are known for. It’s just part of our overall Commando motorcycle rebuild service.


Detailed below is some of what is included in a Complete cNw Commando rebuild. If you are building your own machine and are wanting  individual or partial services, look here  seperate services


Head work


  • New billet valve covers with stainless steel studs and hardware
  • cNw/ARP special head studs
  • cNw/ARP custom head hardware kit
  • Head and cylinder barrel surfaced to insure flatness
  • Combustion chamber volumes are equalized
  • Precision 3 angle cut on valve seats
  • New bronze valve guides
  • New Black Diamond valves
  • New valve springs and insulators
  • New mushroom head tappet adjusters
  • Alloy Tech push rods
  • Rockers and rocker spindles replaced as required
  • New rocker thrust washers and locating springs
  • New cNw stainless steel exhaust nuts
  • New cNw stainless steel, one piece rocker spindle covers
  • Head is bead blasted, pressure washed and media tumble finished
  • Braided stainless steel overhead oil lines with stainless banjos and bolts
  • Improved intake valve seals
  • Aluminized bronze exhaust port inserts
  • New 34mm Mikuni conversion is cNw standard carburetion



Cylinder Barrel and Pistons


  • Pistons, pins and rings are weighted to match within 0.0 (tenth) grams
  • Barrel is surfaced for flatness
  • Barrel is put through a heat cycle to stabilize metal
  • Barrel is ceramic coated with a heat dissipating, high gloss, black finish
  • Barrel is precision bored and honed to correct tolerance
  • Cam followers/lifters are surface ground
  • New pistons
  • Total Seal gapless ring set
  • cNw/ARP custom barrel hardware
  • Special, high strength studs


Lower End


  • New camshaft (several grinds available)
  • New oilpump
  • New billet ignition cover
  • All new crankshaft hardware
  • Rods are weighted to match within 0.0 (tenth) grams
  • cNw/ARP crankcase hardware
  • Crankshaft is magnafluxed, then ground and polished
  • Rods inspected, appropriate repair of nicks, etc.
  • New rod shells
  • cNw breather modification
  • New cam bushings as required
  • Crankcase is bead blasted, pressure washed then media tumble finished
  • Magnet added to sump strainer
  • New Superblend main bearings installed on timing and drive side
  • All crankshaft keys are replaced
  • New cam chain
  • New cam chain tensioner
  • Upgraded tachometer drive seal installed
  • Covers are polished to “show” standard
  • Polished stainless timing cover hardware


Primary Case and Drive


  • New belt drive (except MKIII, std chain drive)
  • Hydraulic clutch conversion
  • New billet outer primary cover (except MKIII, stock show polished cover)
  • New Barnett steel and friction plates installed
  • New hardened clutch center installed
  • Clutch push rod seal by Dave Comeau installed
  • New stainless steel fasteners throughout
  • New stainless inspection caps




  • All new bearings
  • Upgraded lay shaft bearing
  • Transmission case is bead blasted, pressure washed then media tumble finished
  • Gear bushings replaced as required
  • New seals throughout
  • New counter shaft sprocket, specific to 520 “O” ring chain
  • Outer cover machined to accept MKIII kick start shaft seal upgrade
  • Shift shaft o-ring replaced with seal
  • Quadrant and cam plate o’rings are replaced with seals
  • New shift linkage springs installed
  • New MKIII kick starter arm assembly
  • Covers polished to “show” standard
  • All new stainless steel hardware
  • New billet inspection cover


cNw continuously tries to improve on the Norton Commando rebuilds we offer and any of the above may change through the course of your build, however rest assured that its only to make the machine that much better.





Colorado Norton Works