Norton Commando Motorcycle Engine Rebuilds & Transmission Work

Click for info here: Head | Cylinder Barrel and Pistons | Bottom End | Primary Case and Drive | Transmission

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 high quality motorcycle engine rebuilds on time and on budget.

After 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.

If you're rebuilding a Norton Commando motorcycle on your own, but need help with your motorcycle engine work, please visit our Motorcycle Engine & Transmission Rebuild Services page.

Here's what goes into a Colorado Norton Works custom motorcycle engine rebuild:

Motorcycle Head

• New valve covers
• All new studs
• New 34mm Mikuni conversion is CNW standard carburetion
• 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
• Rockers and rocker spindles replaced as required
• New rocker thrust washers and locating springs
• New cast stainless steel exhaust nuts
• New cast stainless steel rocker spindle covers
• New stainless steel head fasteners, complete set
• Glass bead blasting
• "Show" polished rocker covers with stainless steel nuts
• Braided stainless steel overhead oil lines with chrome banjos
• Improved intake valve seals

• Exhaust port thread repair
• Fin repair as required
• Spark plug helicoils

Motorcycle Cylinder Barrel and Pistons

• Pistons, pins and rings are weighted to match within 0.0 (tenth) grams
• Barrel is surfaced for flatness
• Barrel is shot peened, pressure washed and durable high gloss finish applied
• Barrel is precision bored and honed to correct tolerance
• Cam followers/lifters are surface ground
• New pistons and rings
• New stainless steel fasteners
• Barrel base studs are replaced

• Fin repair as required
• Lifter replacement as required, pairs only
• Barrel re-sleeving

Motorcycle Bottom End

• New camshaft (several grinds available)
• New oilpump
• New pointscover
• All new crankshaft hardware
• Rods are weighted to match within 0.0 (tenth) grams
• All crankcase hardware is replaced with new stainless steel
• Crankshaft is magnafluxed, then ground and polished as required
• Rods inspected, appropriate repair of nicks, etc.
• New big end bearings installed
• Crankcase timing side modified for improved breathing as required
• New cam bushings as required
• Crankcase is glass bead blasted and pressure washed
• Crank breather check valve installed
• Anti wet sump check valve installed
• Magnet added to sump strainer
• New main bearings installed
• All crankshaft keys are replaced
• Cam chain and adjuster replaced as required
• Upgraded tachometer drive seal installed
• Covers are polished to "show" standard
• Rods cut down and resized to ensure roundness

• Crankshaft or crankcase replaced if required

Motorcycle Primary Case and Drive

• New belt drive
• New outer primary cover
• New Barnett steel and friction plates installed
• New hardened clutch center installed as required
• New clutch basket bearing installed as required
• Clutch pushrod seal by Dave Comeau installed
• New stainless steel fasteners and replated studs throughout
• New inspection caps

Motorcycle Transmission

• New inner mainshaft bearing installed
• Transmission case bead blasted and pressure washed
• Gear bushings replaced as required
• Upgraded layshaft roller bearing installed
• New mainshaft bearing and seal installed
• New countershaft sprocket, specific to 520 "O" ring chain
• Outer cover machined to accept MKIII kickstart shaft seal upgrade
• New "quad" rings replace all "O" rings throughout
• New shift linkage springs installed
• New MKIII kickstarter arm assembly
• Covers polished to "show" standard
• All new stainless steel hardware
• New inspection cover

• Gear sets as required or requested
• Layshaft or mainshaft replacement if required

We understand that the engine and transmission rebuild is the heart and soul of any custom motorcycle rebuild. At CNW, we take great lengths to perform motorcycle engine work of the highest caliber. Contact us today regarding a complete Commando rebuild, including our motorcycle engine rebuild services. We promise you won't be disappointed once you climb aboard your rebuilt Norton Commando.