Hi, New to Norton Ownership, with a Problem!

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Welcome to the fold Mart.

+1 on checking the seal on the choke plunger. This is a common issue on Keihin & Mikuni carbs ( I think the Mk2 Amal is based on a Mikuni).

As mentioned earlier the wires on Boyer on the stator wires are problematic, and according to Boyer should have a piece of foam placed under the cover to stop the connectors shaking around which leads to the copper strands in the wires breaking under the tie on the stator.

More info here with somebody displaying exactly the same symptoms as you..

www.accessnorton.com

Ran well, now doesn't

I hate to be one of those guys that want their running issues to be diagnosed at a distance, but I'm getting to the end of my rope (and expertise)! '75 MkIII that ran well. I've owned it for a little over 2 years, and haven't done anything much to it regarding engine. PO installed Boyer (mkiii)...
www.accessnorton.com www.accessnorton.com

I and many others have modified the stator, this is my solution..

www.accessnorton.com

Almost Stranded

I was a bit bored today, as my kids have gone back home and my wife was at work. Bike riding is out at the moment as there is about 5 inches of snow outside. So I thought what can I quickly do in the freezing garage? Ideally I want to take a bit off the bike and check or refurb it in the house...
www.accessnorton.com www.accessnorton.com

Good luck, and don't forget to post some pics of your bike.

Cheers,

cliffa.
 
The single Mk2 Amal conversion usually comes fitted with a #15 pilot jet?
 
cash said:
The single Mk2 Amal conversion usually comes fitted with a #15 pilot jet?
Click to expand...

Currently Amal provide a 25 Pilot jet as default but are out of stock.​


RH 36mm 4 Stroke MK II Carburettor - The AMAL Carburetter Company

<p>This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.</p> <p>Comes fitted as standard with:</p> <p>3 Cutaway Sli
amalcarb.co.uk amalcarb.co.uk

​

Details for RH 36mm 4 Stroke MK II Carburettor​

This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.
Comes fitted as standard with:
3 Cutaway Slide
300 Main Jet
106 Needle Jet
25 Pilot jet
 
EstuaryBoy said:
Hi Mart
Whereabouts in Essex???
Great riding weather at the moment..... NOT!!!
:-(
Click to expand...
Mersea Island I'm going to head out shortly, the roads are drying up here.

Tornado, I checked the rubber carb to manifold connector. No sign of aging or splits.
Fast Eddie, the cold start plunger was replaced in 2019, along with the move to a 20 pilot jet. Reading into it, the PO could have had the same problem as me, but can't have cleaned out the tank. I have ordered a 22 and 25 jet plus a couple of spare gaskets!

Mart
 
Mart UK said:
Mersea Island I'm going to head out shortly, the roads are drying up here.

Tornado, I checked the rubber carb to manifold connector. No sign of aging or splits.
Fast Eddie, the cold start plunger was replaced in 2019, along with the move to a 20 pilot jet. Reading into it, the PO could have had the same problem as me, but can't have cleaned out the tank. I have ordered a 22 and 25 jet plus a couple of spare gaskets!

Mart
Click to expand...
I Like Mersea Island... the one i really want to got on is Osea island
 
Still not going to plan on sunny Mersea Island... Last night it idled fine when warm. Not this morning, only firing on choke. Then I noticed some fuel spitting from one of the air vent tubes. Assumed it was the float level. I had checked it before fitting, at 4mm below the top of the bowl. Carb off yet again, slight tweak to the float bracket, check with fuel banjo on = 8mm below top of the bowl. All back together. Still no joy. Starts on choke, will run without the throttle, but dies as soon as I switch it off.

I'm still hoping it's not electrics, tomorrow will look at the choke circuit, but if it's leaking, I'm not sure why it would die as soon as I switch the choke off?

One thing I noticed, the rear right shock vibrated a fair bit. The bottom shock mounting had come out of its rubber bush, leaving it dangling beyond the nyloc nut. I pulled off the nut and checked and reseated the bush in the mounting, with the shoulders visible each side, then tightened it back up. Good hand tight, but not forceful, no space for a torque wrench without removing the silencers, that will have to wait. It now seems firm, but I'll have to keep an eye on it, if I get back onto the road. Nipped up the other side a quarter turn too. Both shocks still have a little play for twisting, but tight.

I don't know how I'd missed that. Re-enforced my view to get an experienced mechanic to check through the bike for safety. Not yet regretting my purchase, but a bit disheartened that I can't diagnose the root of the tickover problem just yet. I'll get there, but probably now need some help on the ground, which I'm trying to organise. :confused:
 
Al's#5 said:
You would never suspect bad fuel these days but, there you go.
Click to expand...
In these days of covid, some gas stations here in the US were giving away FREE E-10. Why? Everyone was staying home and nobody was using fuel. E-10 goes stale from humidity (water) and free is the best way to get rid of it.
 
Mart UK said:
Assumed it was the float level. I had checked it before fitting, at 4mm below the top of the bowl. Carb off yet again, slight tweak to the float bracket, check with fuel banjo on = 8mm below top of the bowl. All back together. Still no joy. Starts on choke, will run without the throttle, but dies as soon as I switch it off.
Click to expand...

As I understand it, the Mk2 float should be set level or just below the top of the float bowl so 4mm would be too low and 8mm worse still.

Mart UK said:
One thing I noticed, the rear right shock vibrated a fair bit. The bottom shock mounting had come out of its rubber bush, leaving it dangling beyond the nyloc nut. I pulled off the nut and checked and reseated the bush in the mounting, with the shoulders visible each side, then tightened it back up. Good hand tight, but not forceful, no space for a torque wrench without removing the silencers, that will have to wait. It now seems firm, but I'll have to keep an eye on it, if I get back onto the road. Nipped up the other side a quarter turn too. Both shocks still have a little play for twisting, but tight.
Click to expand...

It isn't the tightness of the fastener.
The damper retaining washers must be of sufficient diameter to prevent metal damper eyes from sliding off and these washers are standard Commando parts. If the damper eye can slide over the washer then it's no use whatsoever.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

Hi, New to Norton Ownership, with a Problem!
 
Last edited:
Yep MKII float should be paralllel with and just proud of the top of the float bowl. Where are your mixture needles set? Seems like my bikes are running better on one or one and quarter turns out. Maybe the ethanol.
 
Also, the 850 Mk3 lower shock mounting sleeve is wider than the upper (or pre-Mk3 lower mount) and the dimension for the lower mount (0.745" - 0.755") quoted in the Mk3 manual is wrong as it should be 0.942" so additional spacer washers may be required if replacement shocks have been fitted with equal length mounts although Hagon shocks should have the wider lower mount if they are the correct Mk3 type.

06-6489 Norton Commando MK3 Shock Absorbers - HAGON - British Motorcycle Parts Ltd

www.britishmotorcycleparts.co.nz www.britishmotorcycleparts.co.nz
 
Last edited:
Not knowing anything of mkII amals, is there a float needle with viton seal that needs replacing? Could. Be leaking even with float set right.
On the mkI's, I've cleaned up the needle seats using a Q-tip swab in a drill chuck abd a bit of AutoSol metal polish to polish up the brass seat. New viton tipped needles. No leaks.
 
Tornado said:
Not knowing anything of mkII amals, is there a float needle with viton seal that needs replacing? Could. Be leaking even with float set right.
On the mkI's, I've cleaned up the needle seats using a Q-tip swab in a drill chuck abd a bit of AutoSol metal polish to polish up the brass seat. New viton tipped needles. No leaks.
Click to expand...
Also, though no visible air leaks at mani, have you tried a combustible spray on sealing surfaces while running to see if any sucks into engine and changes rpm?
 
Mart UK said:
Still not going to plan on sunny Mersea Island... Last night it idled fine when warm. Not this morning, only firing on choke. Then I noticed some fuel spitting from one of the air vent tubes. Assumed it was the float level. I had checked it before fitting, at 4mm below the top of the bowl. Carb off yet again, slight tweak to the float bracket, check with fuel banjo on = 8mm below top of the bowl. All back together. Still no joy. Starts on choke, will run without the throttle, but dies as soon as I switch it off.

I'm still hoping it's not electrics, tomorrow will look at the choke circuit, but if it's leaking, I'm not sure why it would die as soon as I switch the choke off?

One thing I noticed, the rear right shock vibrated a fair bit. The bottom shock mounting had come out of its rubber bush, leaving it dangling beyond the nyloc nut. I pulled off the nut and checked and reseated the bush in the mounting, with the shoulders visible each side, then tightened it back up. Good hand tight, but not forceful, no space for a torque wrench without removing the silencers, that will have to wait. It now seems firm, but I'll have to keep an eye on it, if I get back onto the road. Nipped up the other side a quarter turn too. Both shocks still have a little play for twisting, but tight.

I don't know how I'd missed that. Re-enforced my view to get an experienced mechanic to check through the bike for safety. Not yet regretting my purchase, but a bit disheartened that I can't diagnose the root of the tickover problem just yet. I'll get there, but probably now need some help on the ground, which I'm trying to organise. :confused:
Click to expand...
Maybe you need a reset of your expectations on these classic machines. This current issue will only be your first. They are an on-going maintence pit. You'll either learn to love troubleshooting and working issues or get put off and sell. My commando is my first classic, had it three seasons and have done loads and loads of stuff to keep it going. Can be frustrating, annoying, but the satisfaction comes from solving and riding what you ha ve wrought :-)
 
Thanks again. Well, it looks like both lower rear shock mountings have 'spacer' type washers, but not the larger washers, which hold the shock on the bolt. Maybe, I have the wrong rubber bushes, so the larger washers wouldn't work. I'll look in the morning, think I'll fit the complete set. So, that was an accident waiting to happen!

I understand the points about float level height, I've read 1.7mm would be optimum. But, I set it at 4mm and fuel poured out of the LH air vent pipe, so I reduced it and it no longer happens. Surely, the fuel will only come out of those pipes if the float valve is still open? Would the angle of the carb affect this? It looks on the horizontal on the centrestand, but not measured it. Am I checking the level correctly, I attach the fuel pipe banjo to the open float bowl (not yet bolted into the carb body, with the float and needle installed, hold it flat and turn on the fuel tap? I don't understand why it flows out of the vent.

Really appreciate your assistance.

Mart
 
Tornado said:
Not knowing anything of mkII amals, is there a float needle with viton seal that needs replacing? Could. Be leaking even with float set right.
On the mkI's, I've cleaned up the needle seats using a Q-tip swab in a drill chuck abd a bit of AutoSol metal polish to polish up the brass seat. New viton tipped needles. No leaks.
Click to expand...
Thanks. The maintenance kit included a new viton tipped needle, which I used.
 
Did you fuel it up at any moment? Avoid the E10. Tank high octane or some premiu kind. And just tocheck: If the valve lash is to tight, it will act up when warmed up.
 
Mart UK said:
Well, it looks like both lower rear shock mountings have 'spacer' type washers, but not the larger washers, which hold the shock on the bolt. Maybe, I have the wrong rubber bushes, so the larger washers wouldn't work.
Click to expand...

If you fit the smaller diameter spacer washers against the sleeve with the large diameter washer on the outside then the shock eye can still move.


Mart UK said:
I'll look in the morning, think I'll fit the complete set. So, that was an accident waiting to happen!
Click to expand...

Well, if you don't fit the wide washer then it's likely the shock will slide off the rubber mount again.
 
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