cNw Engine & Carburetion

Colorado Norton Works offers a variety of motorcycle engine parts and accessories to help you rebuild, install and modify your Norton Commando engine. Choose from options such as our throttle, oil filter adaptor or blanking plates to improve the efficiency of your engine. Or if you’re working on the rebuild of your engine, our motorcycle engine replacement jig and support stand can protect both your engine and your Commando motorcycle during the process.

cNw barrel kit for 750 and 850, cNw / ARP Engine Mount Kit, cNw Stainless steel reverse cone mufflers, CNW / ARP complete crank case kit, Braided Stainless Steel Overhead Oil line, cNw / ARP head mounting hardware, cNw Dual Keihin Flat Slide Carburetor Kit, cNw Dual Keihin intake manifold, Single 34mm Mikuni Carburetor Kit, Hydraulic Clutch, cNw / Lucas / Brembo Master Cylinder Bracket, Commando Heads, Stainless Steel Exhaust Nuts, cNw Breather Modification, 1972 Breather Modification, cNw Tachometer drive blanking plate, Oil Filter Adaptor, Vent Line Filter, Throttle

cNw barrel kit for 750 and 850

Manufacturer:  cNw & ARP

Description:  This kit works with all stock barrels and uses a shorter stud than stock. This will allow you to install the nuts after the barrel is completely seated on the engine cases as opposed to the stock type where you have to start the nuts on the threads well before the barrel is all the way down on the case surface.


  • Stainless studs
  • Studs are short to allow you to install the nuts after the barrel is completely seated
  • Polished ends on studs
  • 12 Point, stainless ARP nuts
  • The 12 point nut allows you to use a closed end wrench to tighten, giving you a far better engagement than an open end wrench
  • Complete kits with studs, nuts and washers
  • Available for both 750 (9 studs) and 850 (5 studs) engines

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cNw part #  0800-28  This kit is for 750 engines (9 studs)

Price $  117.95

cNw part #  0800-29  This kit is for 850 engines (5 studs)

Price $  65.95

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cNw / ARP Engine Mount Kit

Manufacturer:  cNw & ARP

Description:  Simply the best possible hardware to mount your engine to the engine cradle and front Iso mount


  • Type 3
  • Stainless steel ARP bolts, washers and 12 point nuts
  • Special alloy, ‘300 series’ ARP stainless with a tensile strength of 170,000 psi
  • Substantial extra margin of safety over Grade 8 hardware
  • Polished to a high luster
  • cNw modifies these bolts to ensure exact fit for both cradle and Iso mount
  • Available for both Pre MkIII and MkIII engines
  • If you are looking for the best possible hardware available, then this is it

Note:  One small modification is needed to install this bolt kit. A relief needs to be cut on the cases (see 2 images below on the right) and a Dremel tool or similar can be used. This by the upper, right side of the front Iso mount.  A ball end cutter will work the best to remove just enough material so a wrench will fit over the 12 point nut so it can be held securely as the bolt gets tightened. There is a chance that you can grind a wrench down really thin so that it will slip in over the nut but the relief is most likely necessary


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cNw part #  0800-18  up to 1974 engines

Price $  94.95

cNw part #  0800-19  1975, MkIII engines

Price $  94.95


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cNw Stainless steel reverse cone mufflers

Manufacturer: cNw & Cone Engineering

Description:  Due to a void in the market for a high quality, stainless steel muffler we decided to start manufacturing our own.  We made contact with one of the premier custom exhaust manufacturers in the country, Cone Engineering, and started looking at what it would take to make a muffler than not only looked right but also had the sound where were after.   The design is the classic reverse cone style and it’s finished in a high luster polish. The tooling and jigs for this was made from scratch to ensure a round, perfect taper without any variance from one batch to the next. The packing is dense which offer a nice deep sound yet its loud enough to get your attention without being obnoxious.  The polished finish is stunning and the fact that’s its stainless steel, will allow you to re-polish them to remove scuff marks, imprints or anything else that has compromised the finish over time


  • All stainless steel including the internal packing material
  • 20 gauge stainless makes for a rich sound and rigid construction. The throat where is slides over the header pipe is 16 gauge
  • Designed to be used with 1 3/8 header pipes
  • All welds are ground down for a seamless look
  • Show polished finish. Easily re-polished to remove scuff marks etc
  • Clean 2 post mount to fit a std muffler bracket
  • Rich, deep sound but still powerful enough to make your Commando sound better than ever
  • Includes a high quality, stainless steel clamp. This clamp is wide to ensure a secure mount to the header pipe
  • The seam is located on the inside, so there is not a left and right specific muffler
  • Made in the USA

Note:  The cNw logo is CNC machined into the metal on top but on one side only. This means you can install them to show the cNw brand or switch them around from left to right,  if you prefer not to have the logo show


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cNw part # 0500-13

Price $  656.00 pair

 Note: The cNw mufflers are currently sold out. I will have another production run but it will not happen until late fall of 2016. You can certainly contact us to be put on a listto contact once they are back in stock


Contact Us to Order

CNW / ARP complete crank case kit

Manufacturer:  CNW & ARP

Description:  A complete kit to assemble your crank cases


  • Type 3
  • 12 pt ARP 300 series stainless steel bolts and nuts, 170,000 psi
  • The std studs are replaced with bolts
  • Ultra strong and clean kit to match our CNW / ARP engine mount kit on both performance and looks
  • Kit available for 750, 850 and MkIII cases

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CNW part #  0800-23  750 cc

Price $  48.95

CNW part #  0800-24  850 cc

Price $  48.95

CNW part #  0800-25  MkIII

Price $  48.95


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Braided Stainless Steel Overhead Oil line

Manufacturer:  CNW

Description:  A direct replacement for the questionable stock nylon line


  • Strong and flexible stainless steel braided line made by Goodridge
  • Stainless steel banjos made by Goodridge
  • Stainless steel banjo bolts
  • The kit is designed so that the braided lines themselves can be removed for any service work without disturbing the actual banjo and banjo bolts. This way the seal stays intact and makes the kit very user-friendly
  • Fits both 750 and 850 engines
  • Braided lines are not coated since this coating quickly gets compromised and turns yellow in this application


CNW part #  0500-05

Price $  149.95


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cNw / ARP head mounting hardware

Manufacturer:  cNw & ARP (Automotive Racing Products)

Description:  Simply the best head mounting hardware for a Commando in the industry. cNw teamed up with ARP to develop these previously unavailable bolts with a British thread. The kit consists of stainless and high-grade steel fasteners

Update:  Jim Comstock engineering did some testing on an undercut bolt. This essentially stretches the bolt when tightened and allows it to hold a torque more accurately. This modification proved to be a big improvement, especially when using a Copper head gasket. I am now having ARP make the bolts with this undercut


  • Type 3  (see hardware section for Type 3 designation)
  • 5 ea ARP/cNw 12 point head bolts. 3/8 – 26 thread. ARP 300 series, heat-treated stainless that is rated at 180KSI (180,000 psi)
  • The 5 bolts above are also cut down in the center or ‘waisted’ in order to accurately maintain a torque
  • 3 ea ARP head studs. 3/8 – 16 x 3/8 – 24. ARP 8740 Chrome Moly rated at 190KSI. Black Oxide finish
  • 2 ea cNw front barrel studs. 5/16 – 26 x 5/16 – 24. 4140 steel, heat-treated to 40Rc
  • 2 ea cNw 12 point sleeve nuts. 3/8 – 24 thread. 17-4PH Stainless, heat-treated to 42Rc
  • 1 ea ARP 12 point nut. 3/8 – 24. ARP 300 series stainless
  • 2 ea ARP 12 point nuts. 5/16 – 24. ARP 300 series stainless
  • 5 ea ARP washers. 3/8. Stainless
  • 2 ea ARP washers. 5/16. Stainless
  • Fits both 750 and 850 cc heads

Note:  There is one modification needed in order to use that above kit and that is to install ‘heli coils’ or ‘timeserts’  to change the thread for the head studs. Those studs are prone to pull out with the stock thread size and we require that a 3/8 – 16 thread gets installed in order to use the ARP head stud. This service is available from cNw of course if you don’t have a local shop that can do this modification

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cNw part #  0800-30

Price $  199.95 kit



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cNw Dual Keihin Flat Slide Carburetor Kit

Manufacturer: cNw

Description: If you are looking for a carburetor kit that will take advantage of the torque and power in the Commando this is it. The above kit will deliver all the fuel and air that you will need to run your bike to its fullest. It will bolt on any year Commando and everything is included to make it a very easy installation. It’s a tight fit but enough clearance to allow for some engine vibration without making contact with the frame. There is no choke on the carb but the accelerator pump makes it an easy starting system. The two carbs are bolted together so that you do not have to worry about synchronizing. The rollers in the carb-body are there to ensure the slides to operate smoothly and they do make a rattling noise when the bike is at idle. On some tanks the right side petcock will be close to the throttle linkage. This kit was designed for a performance engine and even though you will feel an improvement on a stock engine it really shines if you have some work done to your engine that demands more fuel and air such as a performance Camshaft, Head work etc.


  • Set up your performance engine with a state of the art carburetor kit
  • Unique cNw, CNC machined, billet aluminum intake manifold that has been designed to ensure maximum flow
  • We took a lot of time to ensure that this intake is as efficient as possible. The port floor was lowered and the port has less of an overall radius. The internal texture creates a better air/fuel mixture as it enters the head
  • The intake is  slightly shorter and locate the carbs a bit lower than the older Amal type intakes, creating a little more room between the frame and carb bodies
  • The intake has a built-in balance tube on the bottom so that it does not disturb the air/fuel flow. The balance tube stabilizes the idle and offer a better mixture at low rpm’s
  • cNw unique idle adjuster
  • Intake finish is fully polished. No other finish option is available
  • Keihin FCR 35mm flat slides with rollers to ensure smooth operation
  • The carbs have an Accelerator pump
  • These carbs are bolted together and use a common linkage for operating
  • Rubber adaptors compatible with alcohol modified fuels
  • Stainless hardware
  • K&N Air cleaners
  • Billet spigots
  • Fuel lines with t’s and fuel filters
  • This kit is complete with everything you need from the intake and back to the air cleaners

Don’t hesitate to contact us if you want to talk about whether or not this kit is right for your bike

Note:  There are internal seals on the carburetor that are sensitive to certain fuel additives and octane boosters. Also carburetor cleaners may affect these seals in a negative way. This is not exclusive to these Keihin carburetors but in general so be cautious when choosing additives and cleaning product

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cNw part # 0504-01

Price $ 1799.95


Add #0504-01 to Cart

cNw Dual Keihin intake manifold

Manufacturer:  cNw

Description:  This intake was designed in order to maximize the flow and performance available from the dual Keihin 35mm FCR carburetors and are part of the kit sold above. We are now making this intake available for sale separately for those that already have the Keihin carb kit


  • CNC machined from one piece of  6061 billet aluminum
  • Ports are designed to ensure maximum flow and velocity
  • The ports have an internal texture that allows the fuel and air to mix more efficiently
  • The floor on the intake was put as low as possible to create a greater velocity
  • There is a balance tube on the floor of the ports to stabilize the carbs at idle and low rpm’s
  • The intake moves the carb forward and down compared to the commonly used Amal intake for this application
  • The kit is sold complete with gaskets and socket head allens for installing
  • Shown below is an image of some of the tools  that are used when making this part. There are a total of 23 tools. There are also some images of the machining process. It takes the CNC machine 93 minutes to cut this part
  • When you are looking for the best possible performance from the Keihin carburetors, then this is the intake you will want to use

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cNw part #  0504-12

Price $  289.95


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Single 34mm Mikuni Carburetor Kit

Manufacturer:  Multiple

Description:  A truly complete carburetor kit for your Commando


  • Remove the hard to work with, original Amals, once and for all
  • A 34mm Mikuni VM carburetor
  • Simple set-up and great performance
  • Easy starting and great idle
  • Takes advantage of the low and mid range torque of the engine
  • Easy installation
  • Easy to dial in and adjust. Service parts are readily available at most motorcycle shops
  • One of the most common Commando upgrades
  • This is kit is truly complete with everything from the K&N air filter, all the way through to the throttle
  • Custom made throttle cable with the adjuster under the tank instead of right in front of the handlebars
  • Fuel lines, filters and fuel T’s
  • Includes a tuning manual

Note:  The intake in the kit is not polished like shown on the cNw machine in the image below. If you do want your intake polished, this can certainly be done. Just let me know and I will quote you a cost for this service



cNw part # 0503-01

Price $ 395.95 each


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Hydraulic Clutch

Manufacturer: cNw & Comstock engineering

Description:  Jim Comstock has designed many great upgrades for these bikes and this is one of the best to date. It will transform your rough feeling cable operated unit to a smooth consistent performing clutch. The slave cylinder will mount inside the transmission cover for an extremely clean-looking application. We match the clutch up with a high performance Brembo clutch master cylinder. This is the clutch version of the brake master cylinder that we use with our Brembo front brake kit. Between the master cylinder and slave cylinder we use a stainless steel braided line that has a clear coat cover on it not to be abrasive.


  • Extremely smooth clutch action
  • Lighter pull than the cable units we have used over the years
  • More positive clutch engagement, more like a modern machine
  • No more cable wear and breakage
  • No more cable routing issues
  • The slave cylinder is mounted inside the outer transmission cover for an ultra clean look.
  • The slave cylinder is made from cast steel, as opposed to aluminum, for superior wear characteristics between the clutch piston seal and piston bore
  • Easy to install
  • Fits any Commando transmission


  • The only modification needed is to enlarge the hole on top where the clutch cable used to go through. This is necessary for the solid pipe to fit
  • When installing the Brembo master cylinder the switch cluster that is mounted to the original clutch perch will be lost. This can be replaced with a modern unit like this
  • If you want to retain your original Lucas switch cluster then we also offer this clamp as an option


cNw part # 0600-01

Price $ 459.00


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cNw / Lucas / Brembo Master Cylinder Bracket

Manufacturer:  cNw & Damtech

Description:  This unique adaptor bracket / clamp will allow you to use the cNw front brake system and/or hydraulic clutch kit and retain your original Lucas switch cluster up to 1974


  • CNC machined billet aluminum
  • Allows the use of the original Lucas switch
  • Can be used on right (brake) or left (clutch) side with our Brembo master cylinders
  • Bead blasted (satin alloy) or Black anodized finish
  • Complete with stainless hardware to secure clamp to master and Lucas switch to clamp
  • Threaded mirror perch. 3/8-24

Note:  This type of clamp will not work with a 1975 switch cluster

Note:  When used with the clutch master cylinder, it will locate the switch cluster more inboard (about 1″) on the handlebars and not directly against the grip like stock

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IMG_2662      IMG_2663

cNw part #  0200-10 Satin finish

Price $  89.95 each

cNw part #  0200-11 Black anodized finish (same finish as Brembo master cylinders)

Price $  102.95 each


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Commando Heads

Manufacturer: Fullauto Technologies, Australia. 

Description:  This head is a brand new casting made with modern tooling to achieve superior results in both performance and finish. The head is first cast and then CNC machined to spec. It’s a direct replacement for any Commando engine. Designed to look just like the stock head but when you look closely you will see that the finish, with no casting flaws and imperfections, is far from the original that has a very rough appearance. The core material is also very different from what they used in the old days and you won’t have any issues with porosity as so often is the case with the stock head. Because of the shape of the exhaust ports the velocity is increased and the spent fuel load is forced to exit the head more efficiently. Below are some of the highlights.


  • 6061 T6 aluminum
  • All standard Commando valve train parts will fit.
  • Exhaust ports designed for a more efficient flow
  • Phosphor bronze valve guides are installed
  • Valve seats compatible with unleaded fuels
  • 10% lighter than a stock head
  • Due to material quality, head is far stronger than stock head
  • CNC machined, including combustion chambers to ensure identical volumes
  • Satin blasted external finish
  • ½ inch valve guides
  • Pressure testing is part of the manufacturing process
  • Available for both 850cc and 750cc Commandos

Important notes: The heads are bare with the exception of valve seats and valve guides


cNw part # 0506-01    750 cc version

Price $ 2,795.00

cNw part # 0506-02    850 cc version

Price $ 2,795.00

Note:  We do not stock these heads, so if available with the manufacturer, it’s a special order that will take about 1 week to have shipped to the shop. If the manufacturer is sold out, it may be a several weeks or months before they can be shipped. Contact us for current availability

Contact Us to Order

Stainless Steel Exhaust Nuts

Manufacturer: Darrell Osbourn

Description: Replace your weak stock exhaust nuts with these beautiful Stainless Steel nuts. Superior in strength and also dresses your head up visually. These nuts are hand crafted in limited production numbers and with the highest attention to finish and detail


  • 303 Stainless Steel
  • Profiled V-groove gives superior strength
  • No more distortion, bending or breaking off fins
  • Design allows 24 fins as opposed to the stock 20
  • Beautiful polished face
  • 2 different designs available
  • 2 different thread lengths available

Important notes: There are two different thread lengths available on these exhaust nuts. If you have a header pipe that is Flat at the end, you will need the long thread. If your header pipe has a Conical end using a seat and split ring to secure, then you need the  Short thread


CNW part # 0505-01    750 style.  Short thread version. For use with a dished header pipe

CNW part # 0505-02    750 style.  Long thread version. For use with a flat header pipe

CNW part # 0505-03    850 style.  Short thread version. For use with a dished header pipe

CNW part # 0505-04    850 style.  Long thread version. For use with a flat header pipe

Price $ 249.95 pair

Also see the CNW specific exhaust nut wrench that fits the above nuts perfectly Click here


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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

1972 Breather Modification

Development: Comstock Engineering

Manufacturer: CNW

Details:  There is one Commando engine that was built that will allow the breather to be installed even if the engine is all together. This is the engine built in 1972 that has a large tubular breather installed on the backside of the cases. So it’s located inbetween the transmission and the engine. By removing this original breather and installing our model you will see most of the benefits mentioned above. Due to the fact that we wont be modifying the timing side case half we cannot guarantee 100% performance. It will still outperform any other breather by far. We can of course do the complete modification on this year engine as well if we do have it stripped down completely.

CNW part # 0500-09

Price $ 220.00


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cNw Tachometer drive blanking plate

Manufacturer: cNw

Description: Clean tach drive blanking plate


  • Designed to cleanly cover your tach drive cavity if you don’t run instruments or if you use an electronic tach
  • Alloy
  • Tumble finish (silver apperance)
  • Complete with gasket and polished stainless button head allen bolts


cNw part # 0500-06

Price $ 19.95 kit


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Oil Filter Adaptor

Manufacturer: CNW

Description: Simple and quick modification to convert the threads to an easy to find, modern oil filter


  • Changes the threads on your oil filter housing
  • Simple installation in minutes
  • Allows use of readily available modern oil filters
  • Kit includes an oil filter and a list of filters that can be used


CNW part # 0500-01

Price $ 18.95


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Vent Line Filter

Manufacturer: Tucker / Rocky

Description: Keep from solids leaking out of your oil tank vent line


  • Install at the end of your oil tank vent hose to prevent oil from bleeding out
  • Lifetime filter that is completely washable

CNW part # 0501-01

Price $ 16.95


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Manufacturer: Emgo

Description: Economy throttle but it works well and looks good


  • Vintage look
  • Steel sleeve
  • Chrome housing

Note:  We do modify these to fit the 7/8″ handlebars

CNW part # 0503-02

Price $ 29.00


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