The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: TT John on 20.07. 2022 10:43
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What is the general consensus regarding replacement carbs to an A7 A10 early machine, original Amal mono, concentric, or go for a Japanese PWK, or something of that ilk?
TTJohn
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depends on what you want to do with the bike, ride it or show it, if you want to ride it i use a JRC carb from the usa which is a cousin of the PWK and it works well and it copes with the modern fuels as the yanks have had E10 for many years and it copes with it. very simple carb to setup.
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My bike has its original 2xx series Amal carb. The engine runs a bit rich but I'm happy with how the bike starts and runs.
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Modern Amals work well.
Richard
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They do, and I have an Amal Premier on my A7 which works well. The removable pilot jet is a useful feature in these days of modern petrol which turns to solid after a short while.
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What is the general consensus regarding replacement carbs to an A7 A10 early machine, original Amal mono, concentric, or go for a Japanese PWK, or something of that ilk?
TTJohn
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I bought a new amal monobloc for my A10 works great bought from British Cycle supply they will jet it to your specs
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Good description of the AMAL Premier here
https://www.classicbritishspares.com/blogs/news/amal-premier-carburetors-back-in-stock-2018
The removable idle jet and hardened anodised slide are great improvements.
I have the original Amal Monobloc though and swear by it.
Col
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Concentrics go on just about everything now days
Two reasons
1) no other carburettor will work as well in a dmaged or totally mal adjusted state as a concentric
Not the finest tuning carb but simple & bullet proof
2) reduced inventory of carb bits
I used to have 5 different types of Amals, so the number of bits needed to be kept on hand was massive
I get poo pooed all the time by the rivet counters, but my bikes are for riding and a very important part of riding is being able to return home
If I use $ 5 more fuel who cares, $ 5 is barely bus fare to the railway station .
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The best thing I ever did was buy a brand new Amal for my 1960 A10 GF.
Bolted on and worked a treat from the get go. A few things to note, however....haha as always with old bikes:
1. Use low Ethanol fuel, not E10, as modern fuels leave a green slime deposit which if you leave it to evaporate will cause blocked jets in the Spring.
A great tip from this forum is to shut off the fuel when putting the bike away from a ride and letting it run dry...no more sludge in the float bowl.
2. I fitted a carb offset spacer due to running hot on one pot. This has worked a treat. I try to keep things as standard as possible, works for me.
Good luck
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When I know I've stopped for a while I always let the engine suck the carb dry.
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Thanks for all the answers lads, I have a few carbs lying about so I will have to sort one out. The only reason I was asking for advise is that I have just fitted a NOS barrel & pistons and since fitting I did not think it was quite correct with the PWK, it did run okay with the plus 80s that I had in, before the timing slipped.
TTJohn