Rick's 1975 Norton 850 Commando MkIII Roadster

grandpaul

Author, "Old Bikes"
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Just realized I hadn't cross-posted this restoration project here, so I'll get it caught up a few posts a day till it's up-to-date.

2/22/16
I've been talking to Rick back and forth for a couple of months and we were finally able to get started on his '75 Commando that he bought and hasn't ridden due to multiple issues. I drove to Houston last Friday, after dropping off 2 frames and a bunch of parts at the powdercoater's in San Antonio.

We pulled the bike out of his storage on Saturday morning (parked between his immaculate '74 Trident and nifty '66 BSA Fire/Bolt), and brought it out in the sunlight to discuss particulars. After a quick look-over, I decided to dump a gallon of gas in it and give it a go. Rick mentioned having seen a puff of smoke from under the tank when he tried to start the bike after installing a new battery some time back, so I was careful to look under there when turning on the key, ready to turn it right back off should the need arise. No smoke.

I tickled the carbs and started stabbing at the kicker, and it WANTED to fire, but just wouldn't catch. I asked Rick to tell me more about the new battery and the smoke as I started to pull the battery out of it's dark hole, and immediately found the problem: he had connected the dual red wire to the positive terminal, but had neglected to connect the heavy red ground cable! The red wires were pretty toasty everywhere I could see them; the damage was done, but it was not affecting normal operation once I re-connected the heavy ground cable.

ONE TOUCH on the starter, and it was ticking over quite nicely, although puffing significantly on the left side. As it warmed up, it started smoking on the right side as well. The oil was a bit over-full, so it hadn't "wet-sumped". Possibly intake valve seals dry or off their seats, and/or worn rings (although compression was good).

The bike is a "good ten-footer"; looks nice from about 10 feet away. Any closer and all the minor rust spots, flaked chrome and dry tires show themselves.

The bike's paint is in very good condition, and the engine and starter work well, so this SHOULD be more of a refurbishing than a restoration.

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Re: 1975 Norton 850 Commando MkIII Roadster

Not a bad looking bike, but Rick wants it to be ready to ride anywhere, and totally presentable.

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Apart from the missing air filter, it's all original and complete.
 
Re: 1975 Norton 850 Commando MkIII Roadster

Completely original rear end

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Faded, dull and well-worn, it needs a freshen-up

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MkIII rear wheels tend to be even more skewed than all the typical Commandos

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Paint is in very good condition, pinstripes are a bit sketchy

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Re: 1975 Norton 850 Commando MkIII Roadster

Seat looks decent on this side, but has a few tears on the opposite side

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Very nice paint job on the tank

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Dull front end with the ugly looking chrome brake disk that typically wears unevenly till it gets down to the steel.

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Not too bad till you look close

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Re: 1975 Norton 850 Commando MkIII Roadster

Brake fluid attack, and chipped chunk of throttle cable abutment missing

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Pitted headlight bucket

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Typical perished console decal, 2 of the idiot lights have been replaced. Keyswitch looks wonky...

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Meters look good and work well. Fair original mileage; 'bout time for an overhaul.

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Re: 1975 Norton 850 Commando MkIII Roadster

Missing air cleaner, and new battery

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Very rusty head steady suspension bracket.

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Scrape/gouge on the right side fork leg.

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Crazed and peeling chrome on the headlight ears

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Re: 1975 Norton 850 Commando MkIII Roadster

Rear rim has rust where the chrome has perished (brake fluid damage?); also a few rusty spoke nipples.

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Underside of the engine is relatively clean.

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Front rim has a few rusty spots where the chrome is gone; rusty spoke nipples here as well.

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Ground wires damaged from excessive starting current with heavy grounding cable disconnected. New batteries can do this in about a second and a half.

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Re: 1975 Norton 850 Commando MkIII Roadster

More ground wire damage. I re-connected the heavy ground cable and the bike fired right up.

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Thin chrome on the handlebars is mostly gone.

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Reasonably tidy area under the seat. The Plastic screw holding the sidecover was missing, I happened to have a spare from the JPN (used a new one on the JPN, this one has screwdriver marks). Oil splatter was when I check oil return to the tank; yes, it's returning!

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Seat pan is in miserable condition.

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Re: 1975 Norton 850 Commando MkIII Roadster

Rear grab rail has a couple of scrapes.

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More wiring harness damage from overheated ground wires.

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Rust on the chain guard.

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Cracked iso buffers on the mufflers (typical)

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Re: 1975 Norton 850 Commando MkIII Roadster

Seat hinge will need some attention.

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A few tears on the left side of the seat.

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One tear on the back of the seat.

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Factory was already heading toward shut-down when this bike rolled off the line...

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Re: 1975 Norton 850 Commando MkIII Roadster

I suppose I should insert this here...

Of one thing, I can be POSITIVE: This bike will do the ton EFFORTLESSLY. Just like a modern bike. It won't have a lot left, maybe 115-120 all in, but it gets to the ton without any drama. That puts it right on par with my 2000 Triumph Legend 900 triple, a pretty astounding fact.

This is based on the performance I have experienced with my '75 MkIII Interstate; when you get to the ton, you can hold it there till you run out of gas, it's just breathing free. Personally I wouldn't hold it there for more than a few minutes, I have several other bikes I can do that with, and not chance damaging a somewhat collectible classic.

At any other speed above about 30MPH, the power-to-weight ratio disadvantage vs modern bikes almost disappears. It handles like a dream in the twisty stuff, and has huge handfuls of torque without wearing out your shifting ankle.

Brakes are sub-par with modern bikes, but more than adequate if taken into consideration as you ride.

There is no reason this bike should "mark it's territory" with oil drops, if I do my job right.
 
Re: 1975 Norton 850 Commando MkIII Roadster

Love following your work Paul, I'm in for results on this one.
 
Re: 1975 Norton 850 Commando MkIII Roadster

Rusty turn signal stalks.

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Dull head with rusty bolt heads. Exhaust rose nuts are cracked and bent in a few places.

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Oil filter has been on here for a while.

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Origianl dry cracked rear tire

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Re: 1975 Norton 850 Commando MkIII Roadster

Even worse cracking on the front tire

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The bike has points, but dual 6v coils. Hmmmmmm....

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Looks pretty classy from 10 feet away. The bike runs nice, but smokes. Brakes are BARELY working.

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Rusty patch on the front disc sticks out on an otherwise nice-looking bike.

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Re: 1975 Norton 850 Commando MkIII Roadster

Still 2/22/16...

Pretty clean looking lighting & instrument area

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Gas tank is the nicest thing on the bike.

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If the engine didn't smoke, I'd almost want to leave it undisturbed. Maybe soda blast it and carefully wash it off. But, the smoking exhaust has to be remedied, so off we go...

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Very nice sidecover paint job.

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Re: 1975 Norton 850 Commando MkIII Roadster

The seat looks decent till you get close.

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Original "Bean Can" mufflers are in great shape. They're nice and quiet, but restrictive. Shocks leaked out the hydraulic oil.

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Dull and faded rear end details

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Seat top is okay, but it's going to be replaced with a new cover.

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Re: 1975 Norton 850 Commando MkIII Roadster

Gas tank is in near-perfect shape (inside, too).

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Tidy but old cockpit area.

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Brake fluid tends to migrate and destroy all paint in it's path.

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That's it for the "before" photo shoot.

Next, the tear-down (after several months of waiting for the green light)...
 
10/12/16 (yes, EIGHT MONTHS since I picked the bike up)

Finally received a deposit to get started on this bike, so I got to it.

Starting with an empty parts shelf, and the shop cleaned up and organized (such as it is).

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Tank, fenders, tail light, turn signals, mufflers & seat removed

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Grungiest electrical switch I've ever seen on an old Britbike

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No wonder the left side switch looked so good, it's a new Sparx unit.

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Somebody connected the battery backwards and toasted all the ground wires. This bike is getting a new harness.

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Crispy!

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I got to thinking about the burned wires, and realize what actually happened:

The heavy ground wire for the starter was not connected to the new battery when the old one was replaced. The result was that ALL of the starter's current had the only path to ground through the system's skinny little ground wires (with no fuse to protect it).

TOAST!
 
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