Hi, New to Norton Ownership, with a Problem!

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cliffa said:
Mart, there are some good MK2 troubleshooting tips on pages 4 & 5 here..


And as you can see the float height is, as mentioned earlier parallel with the face.
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Hi, thank you. I had been through the Amal sheet, but not the Triumph one, I will check whether the float is parallel, I dont fancy heating the float bowl with a propane torch to adjust the valve though! TBH, I would expect float level to affect open throttle running, when more fuel is demanded. Currently, my problem is getting it to idle without the choke or without throttle. It will run at 3,000rpm + on the throttle, but dies when I ease off, unless the choke is on. That suggests the pilot circuit is at fault. The pilot jet is fed by an outlet quite low in the bowl, so I don't think whether the fuel level (not the float) is 4mm or level with the top of the bowl should make a difference?
 
L.A.B. said:
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.




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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Yes, I won't ride it until I put those on.
 
I'm still convinced you have an issue with your choke (actually enricher) circuit. There are two very simple checks noted on that bulletin.

Also read this from 2009, post 17 onwards..

Amal Mk2 Carb - simple question

Hi Chaps - the pilot mixture provided by the single Mk2 Amal on my 920 Commando is far too rich (I always suspected this and a Colourtune confirmed it) - I intend to alter the pilot jet - my question - the numbers on the jets - is a higher number a larger or smaller size i.e does a larger...
www.accessnorton.com www.accessnorton.com
 
Tornado said:
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?
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I'll try tomorrow. Will carb cleaner work?
 
Mart UK said:
The pilot jet is fed by an outlet quite low in the bowl, so I don't think whether the fuel level (not the float) is 4mm or level with the top of the bowl should make a difference?
Click to expand...

I think you will find it does as the fuel then has to be raised from a lower level.
 
htown16 said:
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.
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Ah, my fault, the level I've been measuring is the fuel level, not the height of the float. I will check tomorrow and try to get the float parallel and as close to level with the top of the bowl, which I think will lower the fuel level from where I am currently. That might possibly be the issue...
 
L.A.B. said:
I think you will find it does as the fuel then has to be raised from a lower level.
Click to expand...
Yes, that makes sense. I will first check for any leaks at the manifold (the rubber connector), then re-set my thinking on the float, to get it parallel and level with / slightly proud of the bowl.
 
NIX said:
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.
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E10 is coming to the UK, but I used E5, all I can get. I don't think there's ethanol free near me.
 
Mart UK said:
Hi, thank you. I had been through the Amal sheet, but not the Triumph one, I will check whether the float is parallel, I dont fancy heating the float bowl with a propane torch to adjust the valve though! TBH, I would expect float level to affect open throttle running, when more fuel is demanded. Currently, my problem is getting it to idle without the choke or without throttle. It will run at 3,000rpm + on the throttle, but dies when I ease off, unless the choke is on. That suggests the pilot circuit is at fault. The pilot jet is fed by an outlet quite low in the bowl, so I don't think whether the fuel level (not the float) is 4mm or level with the top of the bowl should make a difference?
Click to expand...
If you have the later type black "Stay up" float from Burlen you don't need to move the bush as described there, you can simply bend (very slightly) the metal tang.

If the fuel level is low in the float bowl it is also low in the pilot circuit.
 
Mart UK said:
Ah, my fault, the level I've been measuring is the fuel level, not the height of the float. I will check tomorrow and try to get the float parallel and as close to level with the top of the bowl, which I think will lower the fuel level from where I am currently. That might possibly be the issue...
Click to expand...

Unfortunately, Amal doesn't give a fuel level setting for the Mk2, only Mk1.
amalcarb.co.uk

The All New AMAL Concentric StayUp® Float | AMAL Carburetters

The The All New AMAL Concentric StayUp® Float page for the AMAL Carburetters website.
amalcarb.co.uk amalcarb.co.uk
 
cliffa said:
I'm still convinced you have an issue with your choke (actually enricher) circuit. There are two very simple checks noted on that bulletin.

Also read this from 2009, post 17 onwards..

Amal Mk2 Carb - simple question

Hi Chaps - the pilot mixture provided by the single Mk2 Amal on my 920 Commando is far too rich (I always suspected this and a Colourtune confirmed it) - I intend to alter the pilot jet - my question - the numbers on the jets - is a higher number a larger or smaller size i.e does a larger...
www.accessnorton.com www.accessnorton.com
Click to expand...
Hi, yes, those look like much of my symptoms. Needs checking, even though replaced 18 months ago.. The list is growing!

Mart
 
Mart UK said:
Hi, yes, those look like much of my symptoms. Needs checking, even though replaced 18 months ago.. The list is growing!

Mart
Click to expand...
Possibly the plunger seal was replaced but the choke mechanism is at fault and it's not closing properly. While the bike is running, push down on the top of the plunger and see if it improves things.
 
Mart UK said:
I'll try tomorrow. Will carb cleaner work?
Click to expand...
Carb cleaner, even WD-40 can work. Some use propane torch flowing though a length of hose which you can place right at the mating surfaces around inlet....and even along the head gasket joint to be sucked in a leaking joint. I've used brake cleaner spray and though no leaks found, I did have it set fire to my paper element air cleaner from a bit of back-fire! Be cautious and have extinguisher ready. Try giving the whole carb a push/pull while running to see if flex in rubbers opens anything up/rpm changes/stumbles. I've found leaks on modern air-cooled bonnevilles this way (with injectors hidden inside fake carb bodies).
 
kommando said:

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
Click to expand...
Indeed, but RGM send their single Amal Mk2 34mm carb kit out with the #15 pilot fitted. I ran one for a few years without an issue. My twin 34mm Mk2 Amals currently are fitted with #20 pilots and the air screws are roughly 1.5 turns out.
 
Broke down once on my Matchless 350 which has a Monoblock carb. Ran about 30 miles then failed. Found that I could run it OK on full choke, but cut when choke off. Got me back home OK. Found that the main jet had come loose (but not off), tightened and all was well. Presume that the vibrating jet disrupted the fuel flow up through the needle jet.
 
Same happened to me once on the Commando. Loose but not
off although nearly so.
There are so many small things that used to go wrong on a bike
that I'm sure never happened with modern bikes.
...and don't tell me it is because they don't have carbs! :)
 
Mart UK said:
Fantastic response. Thank you. The original build sheet for the carb conversion, settled on a 15 pilot jet. That was changed to a 20 in 2019. So, I went back to a 15. When I got Berhard's reply, I thought I would swap back in the 20 jet I'd removed. It started, idled roughly, but with the pilot screw out about 5 full turns settled down and will tickover without stalling at about 1,000 to 1,100rpm. Progress. Thank you Bernhard.

I will order a 25 pilot jet tomorrow and believe that could be the solution.

On the ignition comments, I've not ruled it out, but I read previous threads and moved the wiring behind the points cover, it feels fine. Fingers crossed. It had a new wiring loom in 2013, but not a new kill switch.

I did open the fuel cap, to check, no difference, I also cleaned the cap and it leaked fuel on me when I tipped it up, flushing it out! Swooshdave (are you the utube guy? Like the channel), the old fuel was only a couple of days old from my fill up. I stood it in an old Jerry can for a day to settle and poured off the top 2/3 into the lawn mower can. The rest became weed killer. I didnt put it back in the bike, I bought fresh fuel in a clean can for the restart!

Dave, I'm in Essex. I've been emailing the local NOC coordinator, who's put me in touch with a local machanic who specialises in Brit bikes and rides a Commando. Once I've got it running, I'll get him to look it over for anything I've missed / safety check.

I was using the choke / enrichener lever the right way round, but easy to see how it could be confused. Not offended, worth raising.

Really pleased with the replies. Thank you, much appreciated. My feeling is, crap old fuel, low tank, muck in the carbs. Didn't work on reassembly because it was the wrong pilot jet. The pilot air screw is still too far out with a 20 jet, so I will get a 25. I plan a short ride to top the tank up tomorrow and will report back.

Mart
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A bit far away from me then I’m in Cheshire, having said that if we weren’t in lockdown I’d have offered to take a spin down to you. I like a ride with a destination

Dave
 
Update:
I tested the manifold, spraying carb cleaner from both sides with it running on choke and on the throttle off choke. No difference felt.
I toke the choke off and it looked fine at the tip and the bottom of the gallery was clear.
I re-cleaned the bowl and body.
I checked the float. It was very slightly off parallel with the top. The tiniest of adjustments at the tangs (stay-up float) and it was parallel and very marginally above the top of the bowl.

Reassembled everything. Won't now start on the choke. The choke mechanism came out and went back in easily. I didn't disassemble it beyond unscrewing it, checking, squirt of carb cleaner and bolt it back together. Scratching my head.

I have a pic of the bike, the carb and the incorrect shock fixing. But cant see how to attach. Will come back to that.

Mart
 
Dellis said:
A bit far away from me then I’m in Cheshire, having said that if we weren’t in lockdown I’d have offered to take a spin down to you. I like a ride with a destination

Dave
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Appreciate the thought.

It's probably something very simple. Unfortunately, I'm even simpler!
 
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