Amal Premiers

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Never seen anything like that, but I suppose a reaction between the ferrous needle and copper in the brass needle jet is possible, if they’re wet in an electrolyte.
 
My ES2 has a bellmouth on the carb, filters out anything larger than a sparrow, and i haven't seen anything like that on the needle. It does get ridden rail, hail or shine, gravel roads and sealed.
 
the needles are steel with a plated surface finish UK fuel contains Ethanol which means when it vapourises through the needle jet it leaves water residue behind
if the bike is stood with water vapour trapped between the needle jet and throttle needle corrosion takes place and the plating wears off with use

old Amal carbs used brass plated needles so this issue was never noticed , it may be worth checking your main jet holders as well these are steel zinc plated and often rust internally
above the main jet threads there may be a circle of rust

if they increase ethanol content in UK fuel to 10 percent these problems will get worse on old vehicles
 
We appear to be stuck with ethanol, to one degree or another.

What I don’t understand is, why don’t Amal get with the program and start fitting stainless jet holders, brass plated or stainless needles, etc.

It ain’t f***ing rocket science is it...?!
 
Shall pull the inlet rubbers and feel the needles this weekend, if it was purely down to ethanol, then it would be a common find. Considering that these have been about over 6 or 7 years now, surely someone else would have spotted it by now.

A 'gold plated solution' as recommended by Nige would be ideal, for the size of the parts it would not add much cost, the more it is reported the most likely AMAL will react.
 
I cut the needle jet in half last night. Not a pretty picture inside...



I reckon it's the black ring in line with the bottom of the threads which is causing the abrasion to the needle.

Cheers,

cliffa.
 
cliffa said:
I cut the needle jet in half last night. Not a pretty picture inside...



I reckon it's the black ring in line with the bottom of the threads which is causing the abrasion to the needle.

Cheers,

cliffa.
Click to expand...

Has your gas tank ever been sealed or lined? Just looking for some cause other than fuel.
 
Good work Cliff!

I’d say that points towards the moisture / residue sitting there theory.

Maybe look into a fuel stabiliser ?
 
cliffa said:
Standard Ham can filter, I never ride on salted roads, and the slides look like new. I was told that the carbs had only recently been installed when I bought it. I’m not sure which way the blasted side was facing. I’ll have a look at the other one tonight, as I havn’t completely dismantled that one yet. If you zoom in on the real closeup pics it looks almost as though the surface has melted.

Cheers,

cliffa.
Click to expand...


I had the exact same problem. My Premiers are three or four years old, have a standard ham can filter and I (try to) make a point to start my bike every two weeks in the colder months. Well, last Spring about four weeks had past since I started and it when I fired her up the motor ran horribly. I disassembled the carbs and discovered the black mess on the needles. I cleaned them up and the bike runs well now but I'll probably be replacing the needles (as well as the needle jets after seeing your cutaway!)
 
Ethanol?
Sorry , I now see that has already been mentioned several times.
But yeah, ethanol.

It munches on carbs.
 
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Google ethanol, zinc, brass compatibility. There is a chart one may view of various materials and their compatibility with it.
The stuff used to destroy Honda lawnmower, generator, etc. carbs every time they sat for any period without being drained. At least mine suffered that fate...Goldwing not. The Stabilizer has aided in retarding the process for me(annual cleaning now), but my Norton is only recently out of mothballs so I can't remark on the Amals.
I've been hauling ethanol free and am preparing to use pump premium, but don't want this in my future so will look into pros & cons of ethanol neutralizing agents have read of.
 
cliffa said:
I cut the needle jet in half last night. Not a pretty picture inside...



I reckon it's the black ring in line with the bottom of the threads which is causing the abrasion to the needle.

Cheers,

cliffa.
Click to expand...


I recently had that same problem, but on a pair of fork stanchions caused by improper reaming when built. Caused so much stiction that the forks would catch on the springs and not extend compress/extend smoothly at all.
 
I've been out celebrating my 62nd birthday with my wife, Son his girlfriend & some Ethanol free beers followed up my some pure alcohol Grappa, so I'm going to try to answer as many questions as I can in one hit...

1) These needles are not steel.
2) As far as I'm aware the tank has not been lined, but neither have I seen any evidence of rust. I have these permanently in place with a loop of tube going over the top as (1) Easy way to drain the carbs. (2) instant float level / tickler check. (3) Sediment sump. https://andover-norton.co.uk/en/shop-details/20569 - I have never seen any rust or any other material in them.
3) yes in Switzerland there is 5% Ethanol.

Interesting (read depressing) article here on Ethanol...

https://theshopmag.com/features/ethanol-hates-carburetors.

Cheers,

cliffa.
 
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cliffa said:
I've been out celebrating my 62nd birthday with my wife, Son his girlfriend & some Ethanol free beers followed up my some pure alcohol Grappa, so I'm going to try to answer as many questions as I can in one hit...

1) These needles are not steel.
2) As far as I'm aware the tank has not been lined, but neither have I seen any evidence of rust. I have these permanently in place with a loop of tube going over the top as (1) Easy way to drain the carbs. (2) instant float level / tickler check. (3) Sediment sump. https://andover-norton.co.uk/en/shop-details/20569 - I have never seen any rust or any other material in them.
3) yes in Switzerland there is 5% Ethanol.

Interesting (read depressing) article here on Ethanol...

https://theshopmag.com/features/ethanol-hates-carburetors.

Cheers,

cliffa.
Click to expand...
Thanks for that link, those do look useful. One other possibility comes to mind, do you have the oil tank breather routed back to the ham can? Perhaps the vapors from an engine reaching operating temperature are acidic enough to erode the needles?
 
I've never heard of ethanol neutralising substances before. I can't see how ethanol can be "neutralised" - is the term mistaken, and in fact the substances (whatever they are and whatever trade names they're sold under) are actually compensating for the undesirable effects of ethanol rather than neutralising it? Or do they actually react with the ethanol to convert it to something else?
 
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