Norton Commando Build

After 50 years out of production, there are quite a few low-mileage Commandos still out there. One of the main reasons for all these low-mileage examples is previously attempted repairs by less than qualified owners.

After sitting non-running and partially disassembled for 20+ years, this 1974 Roadster is getting a complete overhaul front to back.

Is The Bike Worth It?

The Good Stuff - The frame is good, engine and frame numbers match, it has a clear title, and it came with boxes of original parts.

Other Good Stuff - It's a very low mileage bike, last registered 33 years ago. The speedometer and title show less than 10k miles.

The Bad Stuff - The wiring harness had multiple splices.

Other Bad Stuff - The front forks were badly pitted, and the only solution was to remove and replace the fork tubes.

Read: Front Fork Disassembly

Read: Front Forks Overhaul

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Engine Teardown and Inspection

Although it's a low mileage bike, it's still 50 years old and sat unused for a long time. So, an engine teardown and inspection was in order.

More Bad Stuff - The internal exhaust threads in the cylinder head were stripped, which is not uncommon on Commandos, as the screw-in exhaust nuts often vibrate loose and damage the port threads.

Removing the cylinder head was time-consuming.

Read: Timing Cover Removal and Installation

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Cleaning Motorcycle Spokes

Both front and rear wheels had considerable rust built up on the rims and spokes. The heavy rust was removed with steel wool.

best way to clean rust from motorcycle spokes

During the front forks overhaul, the front wheel was propped up on the workbench and given a thorough cleaning.

After removing the brake rotor, each spoke and nipple was scrubbed with a scuff pad soaked in full-strength degreaser.

This was followed by rinsing with water, then back up on the workbench for a second cleaning, this time with a scuff pad soaked in half-strength degreaser, followed by rinsing with water.

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Brake Caliper Overhaul

Fifty-year-old brake calipers do not come apart without a struggle. Since the bike had sat for decades, there was plenty of concern for the caliper pistons being stuck and corroded.

Before and After Caliper Overhaul

Read: Brake Caliper Overhaul

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Repair or Replace Head?

I contacted Jim Comstock, a well-known Norton specialist. After looking at the pictures, he said that the fins and the exhaust threads were repairable, but he's back-logged with work for at least six months. I emailed several other places, but unfortunately, they don't have the same expertise as Jim does.

Plan "B" was to find a good replacement head. Either way, the old head had to be taken off.

Read: Norton Commando Cylinder Head Removal

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After several weeks of sending inquiries to ebay sellers and classic bike specialists, I found a good used head on ebay.

Upon disassembly, I found that the valve guides and seats were in very good condition. All the head needed was a good cleaning.

motorcycle cylinder head before cleaning

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Cylinder Head Cleaning

In the Norton Workshop Manual, there's a section on how combustion chambers and exhaust ports accumulate carbon deposits, and caution must be given not to scratch the aluminum alloy material while cleaning. Do not use steel scrapers or a screwdriver blade!

"Old School" cylinder head cleaning fits my style and budget - degreaser in a spray bottle, brass cleaning brushes, a little Emery cloth, and a lot of scrubbing.