cNw Modifications

Colorado Norton Works can make your Norton motorcycle run smoother than ever and look better than you could imagine thanks to our complete modifications on rear hubs, transmission seals and oil tanks. While our services will create an eye-catching bike, it will also help protect your custom built motorcycle against wear and tear.

cNw Head Services, cNw Custom Wheels, cNw Oil Tank Modification, cNw Front Hub Modification, cNw Front Drum Hub Modification, cNw Rear Hub Modification, cNw Early Style Rear ‘Bolt Up’ Hub Modification, cNw 1975 MkIII Rear Hub Modification, cNw Breather Modification, cNw Transmission Seal Upgrade

cNw Head Services

All head work performed by cNw & Comstock Engineering

Description:  Exhaust Port Repair

If you have poor exhaust threads we can repair your head once and for all. This exhaust thread insert is a cold install rather than welded in. The welded inserts, because of the heat applied, have a tendency to distort the head which can lead to a number of problems. Rather than putting the head through the stress we machine out the port thread and install our machined aluminum/bronze insert. The installation is permanent. Because of the properties of the aluminum/bronze, it has less tendency to gall and it aids in installation of your exhaust nuts. We still recommend using a lubricant to ensure proper seating. If your head has a weld-in insert we can most likely still repair it with our insert but we need to take a look at the head before proceeding. Call us for additional information

cNw part # 1205-01

Price $ 162.50  per port

Contact Us to Order

Description:  Equalize combustion chambers

We measure the actual volume of each chamber in the head and mill them to ensure that they are identical. This not only affects proper valve train geometry but also the compression

cNw part # 1205-02

Price $ 84.00

Contact Us to Order

Description:  Complete head service

cNw offers a complete head rebuild of your head as well. Below is a list of the parts and services done to the head. We do NOT offer a partial service.

Service Includes:

  • disassemble complete head
  • media blast head and pressure wash
  • media tumble finish
  • install three helicoils and specially made studs to replace the existing head mounting studs. These helicoils with studs are much stronger than the original fine thread studs that have a tendency to pull out of the head.
  • install new bronze guides
  • install new Black Diamond valves and hone guides to correct tolerances
  • cut a three angle valve seat
  • mill gasket surface flat
  • equalize combustion chambers
  • assemble complete head


  • New bronze valve guides
  • New Black Diamond valves
  • New modified head studs
  • New valve spring set
  • New mushroom valve adjusters
  • New adjuster nuts for above
  • New intake valve seals (spring seals not inferior stock seals)
  • New heat insulators
  • New rocker spindles
  • New stainless steel exhaust valve cover studs
  • New stainless steel intake valve cover stud
  • New intake and exhaust, polished stainless, valve cover bolts
  • New rocker spring washers
  • New rocker thrust washers

cNw part #

Price $    Contact us   for current pricing

We also offer additional machining services for the engine   See Here


Contact Us to Order

cNw Custom Wheels

Manufacturer & Builder: cNw & Buchanan’s Spoke & Rim

Description:  cNw does offer a complete wheel building service.  We have teamed up with Buchanan’s Spoke and Rim to offer the highest quality possible. cNw does have an agreement with Buchanans for a show finish, not available from them directly.  Mount a stunning set of fresh wheels on your Commando to take it to the next level of finish and performance.  Of course, we recommend to start with our front and rear hub service to ensure the highest level of finish

Note:  We offer the same pricing as if you were to purchase product and services directly from Buchanan’s

The standard wheel combination on  cNw build is with a 19″ front and an 18″ rear. This combination will give you a far better rear tire selection since a rear 19″ size is virtually obsolete.  We also use a slightly wider rear tire and when the tire gets wider, it also gets a taller side wall. The net result is that our 100/90-19″ front and 120/90-18″ rear actually has the same rolling diameter (height). In other words, the chassis will sit exactly the same as if you were running tires of the same size, front and rear

Also know that a specific width/sidewall height is not necessarily the same when comparing different brand tires. We currently are using the Bridgestone BT45 (performance compound) as a std tire, The rear 120 size has a shaved down sidewall that allows this to fit well inside the Commando swing arm

When getting a tire installed by us it will be a ‘fresh’ tire with a current build date and not an older tire that are often the only ones available at discount outlets

We can of course build your wheels with any rim size and tire combination that you want

Rim design and prices:

  • Sun Rim – wm 3 (2.15) Front $ 236.00 / wm 4.5 (2.75) Rear $ 252.00
  • Excel Rim – wm 3 (2.15) Front $ 227.00 / wm 4 (2.50) Rear $ 248.00
  • Excel Shouldered – wm 3 (2.15) Front $ 260.00 / wm 4 (2.50) Rear $ 260.00
  • Borrani Shouldered – wm 3 (2.15) Front $ 295.00 / wm 4 (2.50) Rear $ 295.00

Build and polish per wheel:

  • Show polish on rim $ 99.00
  • Stainless steel spoke kit $ 110.00
  • Show polish on spoke kit $ 67.00
  • Lace & True 112.00
  • Tires starting at 168.00
  • Tubes starting at 30.95
  • Mount & Balance 74.00

Sun Rim

Excel Rim

Excel Detail

Excel Shouldered Rim



Contact Us to Order

cNw Oil Tank Modification

Modification:  cNw

Description:  Send us your old oil tank and we will do a number of upgrades and modifications to improve on the original design. The original upper mounts fail and when the lower mount gets over loaded it will fracture the tank. If you are fortunate it will only create hairline cracks and the tank will just leak, if you aren’t so fortunate the entire mounting boss and part of the oil tank will come off and the oil will pour out (on your rear wheel to make it all worse) and in a matter of seconds your oil tank will be completely empty. Your sweet old Commando engine is now running without oil and it won’t do that for very long


  • The oil tank gets completely boiled out to remove any sludge and build up. This also strips all paint off.
  • The lower tank mount gets cut off and a plate is brazed over the area to ensure any hairline cracks are covered up.
  • The rear mount is beefed up for added strength.
  • The spigot to the chain oiler (if equipped) is closed up
  • The oil tank is finished in a gloss powder coat
  • The finish is removed to bare metal where it is needed to ensure proper sealing when installed.
  • Included are two rubber mounts that are far stronger than the original.
  • Stainless steel hardware to mount is included.
  • A high density foam pad to install between the battery cover and oil tank is included

Note:  All the modifications are done to the tank you send us. We do no longer offer an exchange service

We do these oil tanks in batches in order to make sense out of the service and keep the cost down. This will allow you to plan ahead as well. Here’s how its works:

  • Each batch is scheduled to start the 1st week of each month
  • If you tank is here on the 1st, it will be included in that batch, completed in the 3 rd week and shipped to you before the end of that same month
  • Regardless when we get the tank during the month, it will get included in the next batch that starts on the following 1st
  • We need the tank only, no attachments

Click on the ‘contact us’ button below for shipping address

Note: This service is not available for the central mounted oil tank used on the 1970 machines. The tank design in the image below is the one we can do the work on

cNw part # 1201-03

Price $ 169.95


Contact Us to Order

cNw Front Hub Modification

Modifications:  cNw

Description:  Transform the dull looking stock hub to a beautiful core to start your wheel build with


  • Entire hub is media blasted, completely sanded & show polished
  • The center spacer is machined to accept sealed, maintenance free bearings
  • Sealed single row and sealed double row bearings are included
  • Hub is assembled and ready to build on

cNw part # 1200-01

Price $ 239.95


Contact Us to Order

cNw Front Drum Hub Modification

Modification:  cNw

Description:  Machine the center of the hub and show polish the ends for a stunning transformation of the rough-looking original hub


  • Media blast and complete sand
  • Machine the center ribs to a uniform, great finish without taking away from the original look
  • Show polish both sides
  • Machine center spacer to accept sealed bearings
  • Service includes a double row and a single row, sealed bearing
  • Hub is assembled and ready to build on

cNw part # 1200-02

Price $ 389.95


Contact Us to Order

cNw Rear Hub Modification

Modification:  cNw

Description:  Don’t spend your money lacing up that nice looking new rim and spokes on that sorry looking old hub. Send us your old hub and let us modify it to an exceptional finish before building your new wheel


  • The rear hub is machined down in the center and on the outside
  • The small fins are retained and that surface is bead blasted for an easily maintained finish.
  • The outer lips are show polished
  • Included in the upgrade are 2 sealed single row bearings
  • Hub is assembled and ready to build on


cNw part # 1200-03

Price $ 279.95


Contact Us to Order

cNw Early Style Rear ‘Bolt Up’ Hub Modification

Modification:  cNw

Description:  Essentially the same rear hub mod that we offer for the cush drive hub but on the early style bolt up hub. A few additional mods are required to complete this hub


  • The hub is machined down in the center and on the outside
  • The small fins are retained and that surface is bead blasted for an easily maintained finish.
  • The outer lips are show polished
  • Included in the upgrade are 2 sealed bearings.  This hub unlike the cush drive, uses one double row bearing and one single row bearing
  • Center spacer gets machined to accept sealed bearings
  • Hub is assembled and ready to build on

cNw part # 1200-04

Price $ 349.95


Contact Us to Order

cNw 1975 MkIII Rear Hub Modification

Modification:  cNw

Description:  Transform the dull looking stock rear hub to a great core for your new wheel build


  • Hub is media blasted, completely sanded and show polished
  • Both bearings installed are sealed and maintenance free
  • Hub is assembled and ready to build on


cNw part # 1200-05

Price $ 199.95


Contact Us to Order

cNw Breather Modification

Development:  Comstock Engineering

Manufacturer: cNw

Description:  We are very excited about offering the most efficient breather modification for Commandos on the market. This kit is developed and designed for maximum performance. We have operated this through a variety of circumstances and rpm ranges and how found it to actually pull a vacuum in the crankcases up to about 4000 rpm. From there to red line it’s virtually running at 0 pressure. The benefits are many and the idea of reducing the excessive pressure in the crankcases that, due to the parallel twin design, will free up the engine and actually create some horse power. It will also virtually eliminate any and all leaks associated with the pressure in the cases. You will notice this where there is a gasket, seal or a material joint. Because of additional modifications that we do in the timing side case to further increase the performance of the breather we are also lowering the operating temperature of the engine oil.

In order to install this kit the engine needs to be completely stripped down as we mill a mounting surface on the lower backside of the drive side case half. We also modify the timing case half.

The above mentioned results are of course directly related to how the engine is built as piston clearance, cylinder bore, piston ring quality, head work, gasket quality and much more will all play a part in how well the engine breather will operate and what kind of results you will experience.

  • Experience an increase in engine performance
  • Eliminate persistent leaks at gaskets, seals, tach drives, head, crank case joints and more
  • Lower the operating temperature of the engine oil
  • The valve can operate consistently during a far higher rpm range than the Commando engine can ever reach
  • The valve is not affected by oil contamination and can perform even if submerged
  • The valve will actually aid in returning the crankcase oil back to the oil tank in case the engine has wet sumped
  • The valve housing is CNC machined out of high quality billet aluminum
  • The valve has an indefinite service life and will not have to be replaced


cNw part # 0500-08

Price $ 265.00

This includes:

  • Milling the drive side case half
  • Modifying the timing side case half
  • All parts necessary to install the breather valve

Special order – Please contact us for information  (not available through online ordering)

Note:  If you have a 1972 engine case, you do not need the machining done. You can install our bolt up version of the valve. Check here


Contact Us to Order

cNw Transmission Seal Upgrade

Machine Work:  cNw

Description:  Modify to outer transmission cover to allow proper seals to be installed


  • Send us your transmission cover and we will machine and install a kick start seal and a shift lever seal to replace the o-rings that are prone to fail and leak.
  • Service includes all parts and machining
  • optional service includes a full prep, sand and show polish.

Note:  Many of the alloy Commando parts and the Transmission covers in particular have a lot of casting flaws that show up like little dimples (porosity). These will not disappear with the polish. The cover will be as perfect as it can get given the core quality

cNw part # 1201-01    Machining and seals

Price $ 89.00

cNw part # 1201-02    Machining, seals and a full prep, sand and polish

Price $ 164.00


Contact Us to Order

Colorado Norton Works