New kid in Nortown

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NKN

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Mar 28, 2016
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Hi to all,
Looking at this forum for a while, I finally was lucky enough to be able to bring back to Europe, in France, a nicely rebuilt 850 MKIIa. Most of the time, I prefer to buy a wreck, or the cheapest one, and have the pleasure to rebuild it. But this time, like I had no spare UK and US screws, bolts, dies or taps or even wrenches, I taught it might be wiser, instead of jumping on the first dirty one, to wait and give a little more money to the guy who would have spent money and TIME rebuilding one.

Finally, this is what I got, and it brings me real happy. Some of you might have seen it on CL.

New kid in Nortown


New kid in Nortown


New kid in Nortown


New kid in Nortown


New kid in Nortown


New kid in Nortown


New kid in Nortown


New kid in Nortown



So now it's here in my place, but I wasn't able to start it yet, for two reasons. When I opened the petcock I saw much too much stuff in the hose, and also the kick was rubbing the exhaust and it wasn't nice to my ears. By the way like I still don't have my license plate so I began to do my first Norton tool and decided to take the carbs off. Because it looks like they didn't have that much care, seals were leaking, gas was stinking and one exhaust header looks like it never was heated. So carbs or electric, no?

And I begin to discover and enjoy all the poetry of the non metric threads, beginning with the need to do my second Norton tool. The two ext. allen screws of the manifold had the same thread but not the same head :roll:

New kid in Nortown


Was happy it was not a fine thread for those ones...

New kid in Nortown


And then, under the carbs, to take the fuel line off, what is the wench size between 1/2" and 9/16". On one screw I was able to put a 13mm wrench, but not on the other.

New kid in Nortown


Can somebody tell me if this little rubber part is at the right place? Is it complete? And what's his job?

Looks like it's time for me to change my glasses :roll:

New kid in Nortown


New kid in Nortown


New kid in Nortown



Here are some pictures of the sliders. Are they already completely worn? Do they look they have the same mileage than the odometer, around 12'000 miles? Like I would stay classic at the moment, what's the best choice now, buy some new brass chromed ones, have those ones polished and anodised?

Thanks for your help.
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Hi, welcome. Nice looking bike! The "rubber part" would be the steel tickler, as it should be.
Thos Amal carb fittings are Whitworth, (3/16, IIRC). The carbs, and slides wear. If those are original, and have significant miles/km's on them, replace with a nice pair of new Amal Premiers.
 
Welcome.

NKN said:
And I begin to discover and enjoy all the poetry of the nonmetric threads, beginning with the need to do my second Norton tool. The two ext. Allen screws of the manifold had the same thread but not the same head :roll:

Actually, they are probably not exactly the same thread.
The screw on the left is probably 60 degree UNC and the screw on the right is the original and correct 55 degree Whitworth thread.



NKN said:
And then, under the carbs, to take the fuel line off, what is the wrench size between 1/2" and 9/16". On one screw I was able to put a 13mm wrench, but not on the other.

The hexagon/spanner size is 1/4W (0.525", 13.34mm)


NKN said:
Can somebody tell me if this little rubber part is at the right place? Is it complete? And what's his job?

Rubber part? No. It looks as if someone has attempted to block off the tickler hole if it has rubber in it? Edit: It's possible somebody added the rubber to prevent the tickler pin from damaging the float?


NKN said:
Here are some pictures of the sliders. Are they already completely worn?

Yes. Or, at least, somewhat past their best.

NKN said:
Do they look they have the same mileage than the speedometer, around 12'000 miles? Like I would stay classic at the moment, what's the best choice now, buy some new brass chromed ones, have those ones polished and anodised?

Personally, I would replace with new genuine Amal anodised slides, that's if the bodies aren't also worn out.
 
L.A.B. said:
NKN said:
And I begin to discover and enjoy all the poetry of the nonmetric threads, beginning with the need to do my second Norton tool. The two ext. Allen screws of the manifold had the same thread but not the same head :roll:

Actually, they are probably not exactly the same thread.
The screw on the left is probably 60 degree UNC and the screw on the right is the original and correct 55 degree Whitworth thread.

You are probably right as there is 3 like the right one.

L.A.B. said:
NKN said:
And then, under the carbs, to take the fuel line off, what is the wrench size between 1/2" and 9/16". On one screw I was able to put a 13mm wrench, but not on the other.

The hexagon/spanner size is 1/4W (0.525", 13.34mm)

OK, always good to know

L.A.B. said:
NKN said:
Can somebody tell me if this little rubber part is at the right place? Is it complete? And what's his job?

Rubber part? No. It looks as if someone has attempted to block off the tickler hole if it has rubber in it? Edit: It's possible somebody added the rubber to prevent the tickler pin from damaging the float?

Hoho, I said rubber because it looks like that, but I didn't check them, and they are on both carbs.

L.A.B. said:
NKN said:
Here are some pictures of the sliders. Are they already completely worn?

Yes. Or, at least, somewhat past their best.

L.A.B. said:
NKN said:
Do they look they have the same mileage than the speedometer, around 12'000 miles? Like I would stay classic at the moment, what's the best choice now, buy some new brass chromed ones, have those ones polished and anodised?

Personally, I would replace with new genuine Amal anodised slides, that's if the bodies aren't also worn out.

OK, I'll check them from inside.


Thanks for welcoming, and special thanks to L.A.B. for spending his precious time to answer me. :wink:


Next step is electricity. There are some free wires, could somebody tell me what are they supposed to power?

New kid in Nortown



White arrow goes to the battery I presume, but where are going the blue and green ones?


New kid in Nortown


Last question for today, what is this hole standing for?
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NKN said:
Next step is electricity. There are some free wires, could somebody tell me what are they supposed to power?

NKN said:
White arrow goes to the battery I presume, but where are going the blue and green ones?

"Green arrow" look like the wires that would normally connect to the Lucas rectifier.
If so, they will be:
Brown/blue
White/green
Green/yellow
Red.

New kid in Nortown




Brown/blue (blue arrow) would normally connect to the Zener diode (voltage regulator) also, the double red with the ring terminal attached to the upper side panel bracket in the photo would normally connect to the inside of the right-hand Z plate close to the Zener (see 2nd. image below).



NKN said:
Last question for today, what is this hole standing for?

That is where the Zener diode would normally be mounted.

New kid in Nortown


Dirt2Oil said:


Edit:
NKN said:
a nicely rebuilt 850 MKIIa

What makes you think it's a Mk2A? As it has none of the usual 'A' parts, and as it's a US model it is more likely to be a Mk2.
 
Hello and welcome to this forum. The hole as shown in your last picture is where the zener diode was originally fitted.
It is possible that the previous owner made some modifications on the electrical system, so check carefully.
The stock wiring harness of the Commano has some wires that are not in use at all, can be confusing indeed.
Personally I would take a look at the wirimg diagram in the manual and check the elec sytem.

EDIT :It looks like LAB and I were posting their reply at the same time.
 
Welcome to the forum!

The extra wires (green arrow) are for a 2-horn system with relay (for police bikes)

The blue arrow points to a power wire that is either from the top of the rectifier (12VDC out), or to the keyswitch (depending on the model/year), or to the 2MC capacitor (larger terminal), or to the Zener diode that has been eliminated.
 
grandpaul said:
The extra wires (green arrow) are for a 2-horn system with relay (for police bikes)

If they were the Interpol twin horn wiring (which I doubt) then they would be purple/black, brown/black, brown/purple, green/purple and brown/blue.

grandpaul said:
The blue arrow points to a power wire that is either from the top of the rectifier (12VDC out), or to the keyswitch (depending on the model/year), or to the 2MC capacitor (larger terminal), or to the Zener diode that has been eliminated.

The particular brown/blue has a 3/8" female spade terminal, so it has to be the Zener diode connection.
 
Welcome to the forum. That's a nice looking Commando.

May I suggest that the first "tool" you should buy for your bike is a factory service manual? They have excellent wiring diagrams with all the color codes on the wires. There are also digital versions of the manual available free on-line for some of the Commando models. Or, you can buy the Norton CD from Kim the CD Man, which has service manuals, parts books, service notes, etc. You can email Kim at kimthecdman@techinfo.com.au.

Ken
 
L.A.B. said:
What makes you think it's a Mk2A? As it has none of the usual 'A' parts, and as it's a US model it is more likely to be a Mk2.

I have to agree with L.A.B. this Norton appears to be an 850 Mark 2 not a Mark 2A. However the bike does have the Mark 2A rectifier bracket part number 06-4974. This part is sandwiched between the upper side cover bracket and the rear frame plate. Mounting the rectifier to this bracket wouldn't work because the side panel would be in the way. This is not the first time that I have seen a Mark 2 with this bracket. I am wondering if the later Mark 2's were supplied with this bracket simply to guide the chain oiler hose, brake wires and possibly the battery vent. Of course on this particular bike that bracket serves absolutely no purpose.



Peter Joe
 
PeterJoe said:
Mounting the rectifier to this bracket wouldn't work because the side panel would be in the way. This is not the first time that I have seen a Mark 2 with this bracket.

Here's what appears to be another Mk2 model with the "rectifier" bracket. Note the position of the rectifier.

PhiloMcGiffin said:

PhiloMcGiffin said:
 
concours said:
Hi, welcome. Nice looking bike! The "rubber part" would be the steel tickler, as it should be.
Thos Amal carb fittings are Whitworth, (3/16, IIRC). The carbs, and slides wear. If those are original, and have significant miles/km's on them, replace with a nice pair of new Amal Premiers.

I just put the sliders back in the carbs to measure the play and all I was able to put between both was a 0.05mm= 0.001968504in feeler gauge. Doesn't look that bad for me, no?

BTW I'll might change them to be trouble free.
 
Peter R said:
Hello and welcome to this forum. The hole as shown in your last picture is where the zener diode was originally fitted.
It is possible that the previous owner made some modifications on the electrical system, so check carefully.
The stock wiring harness of the Commano has some wires that are not in use at all, can be confusing indeed.
Personally I would take a look at the wirimg diagram in the manual and check the elec sytem.

EDIT :It looks like LAB and I were posting their reply at the same time.

L.A.B. said:
grandpaul said:
The extra wires (green arrow) are for a 2-horn system with relay (for police bikes)

If they were the Interpol twin horn wiring (which I doubt) then they would be purple/black, brown/black, brown/purple, green/purple and brown/blue.

grandpaul said:
The blue arrow points to a power wire that is either from the top of the rectifier (12VDC out), or to the keyswitch (depending on the model/year), or to the 2MC capacitor (larger terminal), or to the Zener diode that has been eliminated.

The particular brown/blue has a 3/8" female spade terminal, so it has to be the Zener diode connection.

grandpaul said:
Welcome to the forum!

The extra wires (green arrow) are for a 2-horn system with relay (for police bikes)

The blue arrow points to a power wire that is either from the top of the rectifier (12VDC out), or to the keyswitch (depending on the model/year), or to the 2MC capacitor (larger terminal), or to the Zener diode that has been eliminated.


Thanks to the three of you for bringing me some light in the dark electric spaghetti plate.
 
L.A.B. said:
Edit:
NKN said:
a nicely rebuilt 850 MKIIa

What makes you think it's a Mk2A? As it has none of the usual 'A' parts, and as it's a US model it is more likely to be a Mk2.


It was sold as an MK2A, it's my only reference at the moment. What's the differences between both?
 
NKN said:
It was sold as an MK2A, it's my only reference at the moment. What's the differences between both?

Both the Mk2 and Mk2A were made during the same production period but were slightly different models intended for different markets.

The Mk2 had peashooter silencers, perforated metal airbox and was the model mainly sold in the US and Canada in '74.

The Mk1A and Mk2A were low noise emission models originally intended to be sold on the European market (although we know some 2A models were later sold in the US).


The main features of the 'A' models (Mk1A and Mk2A) were annular discharge silencers and black plastic airbox, the original annular discharge silencers have usually been replaced with peashooters by now and owners often removed the plastic airbox, however, the A models also have a number of other A-specific parts, such as kickstart lever, oil junction block, battery tray that positioned the battery across the frame (because of the larger airbox) and left-hand side panel secured by a Dzus fastener in a recess at the lower rear of the panel, the Dzus receptacle mounted to a bracket on the battery tray.

Your model appears to have none of those 2A parts, with the exception of the rectifier plate which may not have been a 2A-only component.
 
L.A.B. said:
The main features of the 'A' models (Mk1A and Mk2A) were annular discharge silencers and black plastic airbox, however, the A models also had a number of other A-specific parts, such as kickstart lever, oil junction block, battery tray that positioned the battery across the frame (because of the larger airbox) and left-hand side panel secured by a Dzus fastener in a recess at the lower rear of the panel, the Dzus receptacle mounted to a bracket on the battery tray.

Your model appears to have none of those 2A parts, with the exception of the rectifier plate which may not have been a 2A-only component.


But I do have the left-hand panel secured by a Dzus fastener... but in the top left of the panel.

BTW the show must go on, what is the easiest and cheapest way to sell a "real" matching numbers' bike? Just buy a new frame plate and copy, even clumsily, the engine number. :lol:

New kid in Nortown
 
Carbs also have some mysteries for me. Numbers on the body looks different: R35 vs L36

New kid in Nortown


New kid in Nortown


And the sliders are playing the same game: 3 vs 4

New kid in Nortown


Perhaps it's the reason why only one header is blue?
 
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