Newbie but oldie

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Hello all,

First let me thank you for this forum! What a resource!!!

I have a 1975 MKIII that I haven't ridden since 1989 and would like to at least get it running. It was stored for many years in my airplane hanger which would get quite humid in the spring. It has always turned over OK.So far, I've cleaned it up a bit, pulled the plugs & fogged the cylinders and many other things with Sea Foam deep creep.
I've forgotten many things over the years:
-I can't get the seat lock to unlatch but don't remember, was it keyed the same as the ignition, or is there a separate key?

-I have some electrical skills, remember that the bike is positive earth, so just to check preliminary response I checked some basic things with my multimeter to rule out major short circuits. When there were none, I connected my battery charger properly just to see if the horn would work etc. There was basically zero current draw no matter what switches I tried. Any suggestions where I should start looking?

-Has anyone had any luck with new gas tank sold on ebay from India?

Thanks so much for any and all help!

Newbie Randy
 

grandpaul

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Battery is dead, more than likely.

You'll want to do an oil change, for sure (with filter). Engine, transmission, primary chaincase, and forks.

Carbs will need to come off and have a good soak in a gallon can of Berryman's Chem-Dip (leave the can in the sun a while to warm it up, AFTER cracking the lid open). Dismantle one at a time, don't mix up the parts.

Some tanks from India are good, some are NOT! If you can't find good enough answers in the SEARCH feature (top right), ask that question specifically (in a new thread) to get the most visibility and valid replies.

Worst case, use the leftover Berryman's sloshing around in the tank (after you do the carbs), then flush REALLY WELL with some cheap gas, let dry in the sun (again, if you have any of that)

Different key on the seat I THINK (don't remember either).

Welcome, and get with it!

P.S. What's in your hangar?
 

gortnipper

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Welcome Randy.

I left my bike in a big steel shed with concrete floor here in NZ for 10 years, unridden and unstarted. Pretty humid and about 15klicks to the sea. One of the cylinder walls had pitted in contact with the rings, and was lucky that a +.040 job on it worked ok. So, you may want to get one of those cheap USB driven boroscopes to put down the plug hole and look around.

Make sure you check this out - https://www.accessnorton.com/NortonCommando/technical-information.2265/

The book we all wish we had when we started has just been published.

Norton Spare Parts - Genuine Norton Parts - Norton Motor - Norton Motorcycle - Norton Commando

Also available on Amazon and ePay,
 

L.A.B.

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I can't get the seat lock to unlatch but don't remember, was it keyed the same as the ignition, or is there a separate key?

The seat lock key is different.

-I have some electrical skills, remember that the bike is positive earth, so just to check preliminary response I checked some basic things with my multimeter to rule out major short circuits. When there were none, I connected my battery charger properly just to see if the horn would work etc. There was basically zero current draw no matter what switches I tried. Any suggestions where I should start looking?

Difficult to say without more detailed information.

Power (brown/blue, NU) should be reaching the ignition switch (Terminal 1) from battery (-).

With the ignition key at 'Ignition only', the switch should connect NU-W.
At 'Ignition and Lights', NU-W-NG-UY.
At 'Parking with lights' NU-NG.

Keyswitch_zps5fwcgych.jpg


Lucas4PositionIgnitionSwitch004-1.jpg



-Has anyone had any luck with new gas tank sold on ebay from India?

Roadster Hi-Rider or Interstate? If Roadster then the popular choice is Emgo (Taiwan).
 

YING

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Buying a tank from India is a crap shoot. I bought one and after much re-working it works and has stayed good for 3 years. I would not do it again but other people may have had a better experience. I went round and round with the vendor to no avail.The Emgo Roadster tank have received some positive reviews.Just my 2 cents
Mike
 
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Hello all,

First let me thank you for this forum! What a resource!!!

I have a 1975 MKIII that I haven't ridden since 1989 and would like to at least get it running. It was stored for many years in my airplane hanger which would get quite humid in the spring. It has always turned over OK.So far, I've cleaned it up a bit, pulled the plugs & fogged the cylinders and many other things with Sea Foam deep creep.
I've forgotten many things over the years:
-I can't get the seat lock to unlatch but don't remember, was it keyed the same as the ignition, or is there a separate key?

-I have some electrical skills, remember that the bike is positive earth, so just to check preliminary response I checked some basic things with my multimeter to rule out major short circuits. When there were none, I connected my battery charger properly just to see if the horn would work etc. There was basically zero current draw no matter what switches I tried. Any suggestions where I should start looking?

-Has anyone had any luck with new gas tank sold on ebay from India?

Thanks so much for any and all help!

Newbie Randy
So, after finishing some other looming projects, I got back to the Norton today. I did buy a new tank and side covers from someone in India, and although I was convinced I was going to be scammed, the parts finally arrived about a month ago. I paid <$275 including shipping for the 3 pieces, and I am very surprised to say that the quality & paint job so far looks to be very good. They were carefully packaged and arrived in perfect condition. I was VERY surprised!!! I haven't put fuel in it yet, but the parts fit, and the inside of the tank appears to be rust free.

In preparation for possibly trying to start it, I pulled the rocker covers and pivot access plates to lubricate since it hasn't been run since the 80's. To my surprise, there was NO rust in there and it still had oil on the parts! I sprayed some lube in there just for good measure.

I'd rebuilt many carburetors in the day & in another life, so I think I can do that. I'm gaining interest in getting it to run.

BUT, the electrical system is the unknown at this point. I can't get signs that anything is working; I did some preliminary checking by looking for resistance changes across the battery connections (no battery) with a multimeter. I know that limey bikes are positive earth. I assume I should see SOME resistance change from infinite to some measurable resistance when I turn the ignition on, and try the horn and other switches. I get NO change.

So far, I've checked the inline fuse & connections, and the cleaned up the spade connectors on the block next to where the battery sits. I still get nothing. I do get good continuity between ground and the red, and the 2 stripped wires that connect to the battery. There is NO circuit to ground from the black battery wire, which is what I would expect.

I think I remember replacing the points & condenser with a breaker less system, but don't remember what kind it is.

I'm attaching a couple pictures of the tank and wiring at the battery in case that is helpful.

Thanks in advance for any insight you have!

Randy




 
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It's in very good shape.
New battery yes, all oils changed.
You could purchase a more modern ignition , time has gone by.
The tires must be changed too for safety reasons, the layshaft bearing upgrade is much more involved but there are threads on this.
You will need the clutch puller tool.
 

gortnipper

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So, after finishing some other looming projects, I got back to the Norton today. I did buy a new tank and side covers from someone in India, and although I was convinced I was going to be scammed, the parts finally arrived about a month ago. I paid <$275 including shipping for the 3 pieces, and I am very surprised to say that the quality & paint job so far looks to be very good. They were carefully packaged and arrived in perfect condition. I was VERY surprised!!! I haven't put fuel in it yet, but the parts fit, and the inside of the tank appears to be rust free.

In preparation for possibly trying to start it, I pulled the rocker covers and pivot access plates to lubricate since it hasn't been run since the 80's. To my surprise, there was NO rust in there and it still had oil on the parts! I sprayed some lube in there just for good measure.

I'd rebuilt many carburetors in the day & in another life, so I think I can do that. I'm gaining interest in getting it to run.

BUT, the electrical system is the unknown at this point. I can't get signs that anything is working; I did some preliminary checking by looking for resistance changes across the battery connections (no battery) with a multimeter. I know that limey bikes are positive earth. I assume I should see SOME resistance change from infinite to some measurable resistance when I turn the ignition on, and try the horn and other switches. I get NO change.

So far, I've checked the inline fuse & connections, and the cleaned up the spade connectors on the block next to where the battery sits. I still get nothing. I do get good continuity between ground and the red, and the 2 stripped wires that connect to the battery. There is NO circuit to ground from the black battery wire, which is what I would expect.

I think I remember replacing the points & condenser with a breaker less system, but don't remember what kind it is.

I'm attaching a couple pictures of the tank and wiring at the battery in case that is helpful.

Thanks in advance for any insight you have!

Randy




Take a look at @gtiller 's great site for.wiring diagrams.


Take off the points cover (small round cover lower front right of motor) and post a pic and it will get identified.

Also, manuals.

https://britmoto.com/manuals/Manuals/Riders_4.pdf



 
Last edited:

illf8ed

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Are you having continuity problems from one point to another across a plug connector? Humidity won’t have been kind to the rubber cover with thin metal connectors that hold the wiring bullets together. The metal either corrodes or breaks. I assume no one has moved the wiring connections around.
 
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Thanks! I'll have a look at some of the bullet connectors today.

Just to be sure, looking at the picture below, the two red wires and the orange striped one that I have together in the picture get connected to the battery negative terminal, and just the one black one gets connected to the positive terminal, right?

I seem to remember having to change connections around to one or two of the smaller red and orange striped wires when I installed a breaker less ignition 30 years ago.

I'll also take the points cover off and take a picture of the breaker less system.

20210405_160346_HDR.jpg

 

L.A.B.

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Just to be sure, looking at the picture below, the two red wires and the orange striped one that I have together in the picture get connected to the battery negative terminal, and just the one black one gets connected to the positive terminal, right?

In your first post, you said...:
-I have some electrical skills, remember that the bike is positive earth

...in which case you don't want to connect the earth wires to battery negative.
The wire with the fuse holder should be the negative (connected to brown/blue under the tape?) so connects to battery(-) along with the heavier gauge black (to solenoid) wire.
That orange/black 'earth' wire (connected to harness red?) shouldn't really be connected to the battery(+) at all if there is a working starter motor.
Heavy gauge red to battery(+).

Edit: Something else you said previously:
There is NO circuit to ground from the black battery wire, which is what I would expect.
...Because the heavy black battery wire isn't earth/ground.
 
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Yes, the black wire has no continuity to ground...frame or motor, so assume it connects to the negative post since the bike is positive earth.

The two red wires and orange striped wire all with ring terminals do have good continuity to ground, zero resistance, so I assume all three get connected to the positive post, right?

Thanks for the help!
 

L.A.B.

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Yes, the black wire has no continuity to ground...frame or motor, so assume it connects to the negative post since the bike is positive earth.

No need to assume.
As I said:
The wire with the fuse holder should be the negative (connected to brown/blue under the tape?) so connects to battery(-) along with the heavier gauge black (to solenoid) wire.

The two red wires and orange striped wire all with ring terminals do have good continuity to ground, zero resistance, so I assume all three get connected to the positive post, right?

No.
As I said:
The wire with the fuse holder should be the negative (connected to brown/blue under the tape?) so connects to battery(-) along with the heavier gauge black (to solenoid) wire.
That orange/black 'earth' wire (connected to harness red?) shouldn't really be connected to the battery(+) at all if there is a working starter motor.
Heavy gauge red to battery(+).

The section of wire attached to the fuse holder with the ring terminal would not normally be red* (should be brown/blue) as that is the negative, Edit: therefore, only the heavier gauge red should be connected to battery(+).

*(Looks as if somebody could have put that wrap of black tape on the red wire close to the terminal as a reminder that it's negative?)


1975-MK3-Commando-Original.png
 
Last edited:

L.A.B.

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No need to assume.
As I said:




No.
As I said:


The section of wire attached to the fuse holder with the ring terminal would not normally be red* (should be brown/blue) as that is the negative, Edit: therefore, only the heavier gauge red should be connected to battery(+).

*(Looks as if somebody could have put that wrap of black tape on the red wire close to the terminal as a reminder that it's negative?)


1975-MK3-Commando-Original.png
Thanks so much for your patience! Sorry I was thick about this, It's been such a long tome since I've putzed with a limey bike. I now remember Norton changed the conventional red=hot, black=earth wire colors at some point to prevent yanks from hooking the battery up backwards. As a teenager I had a couple bikes that used conventional wire color, a Matchless 500 single, and a Matchless 650 twin.
 
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