Tinkering with Binks

It struck me that I get a lot of enquiries abut vintage carbs owing to the Amac post I did some time ago so I decided to put in a bit about Binks.

See, I had a message from a chap called Peter asking if I could identify the AMAC carburetter fitted to his Monet Goyon two-stroke as he couldn’t find anything like it on the internet. As with most vintage components, there doesn’t seem to be much reliable info around, certainly not on the web, but also in books. It’s a common problem; back in the day, if you had an issue with a component on your motor cycle you telegrammed the manufacturer ‘who would be pleased to assist you’. By the time he went out of business (probably due to spending too much time answering sodding telegrams for nothing) the bike would be worn out anyway so nobody cared too much about saving the information. So today anyone who dabbles in the dark world of ancient motor cycles and needs this information is likely to find it very scarce.

By analysing any carburetter that comes my way and recording differences and settings, I am trying to get enough information to unravel the mystery. I don’t have much in the Binks line but thought it was worth answering Peter’s question here, because while my knowledge is very limited there may be others, apart from Peter, who would find it useful. Also the stupid computer bounced my reply to Peter for some reason, so I hope he will find it!

Here’s Peter’s picture of the carb he is trying to identify…

floatchamberlid At least it’s easy to see why he is struggling to find it on the web; it isn’t an AMAC at all; it’s a two jet Binks that has been fitted with an AMAC float chamber lid.

It’s not altogether unusual for it not to have its original lid because while Binks fitted a clever spring clip to prevent the float chamber lid from vibrating off, unfortunately the ears that hold the clip sometimes break but most of all, the cap itself is a zinc-alloy die casting, the material of choice for detailed castings like the Binks cap with its  ‘C.BINKS (1920) LTD ECCLES’ lettering. Unfortunately, while popular with carb manufacturers ever after for its ability to follow intricate casting moulds, zinc alloy (also affectionately known as ‘shit metal’) is fragile and very prone to crumble with age. A nice brass AMAC float cover is a far better thing – and also in short supply – so Peter could probably get a swap.

History tells us that AMAL stands for Amalgamated Carburettors Ltd. The amalgamation happened late in 1927 and consisted of AMAC, Brown and Barlow and Binks. In a letter to shareholders printed in Motor Cycle and Cycle Trader magazine it was explained that amalgamating the three companies – of which Nobel Industries-owned AMAC was clearly the largest – would avoid the current impossible situation of having to predict which manufacturers would want which make of carb, forcing each to hedge their bets on production quantities. Also since each of the manufacturers held patents for certain desirable design features, it had become impossible to make ‘the perfect carb’. An amalgamated company could pool resources and operate effectively without competition..

Charles Binks (1920) Ltd brought a multi jet system to the party. This is Charles, fiddling with one of his early devices…

He had devised a two jet carburettor with a pilot jet system in his early days, having been dissatisfied with the poor slow-running performance of contemporary instruments. This led onto the famous ‘three jet’ and the sports models ‘Mousetrap’ and racing ‘Rat-trap’. Charles himself didn’t live to see the amalgamation, he passed away in 1922.





Peter’s carb is broadly one of these…


…known as the Type A (well, there is another letter indicating size – eg HA for a 1927 3/ 4″  . choke diameter.

This one is a two jet, single lever model. The term ‘single lever’ means it is operated by a single control lever as opposed to a dual lever, like an AMAC where you have to adjust both air and throttle as you ride. A single lever carb can, of course, thus be operated by a twistgrip, which was another of Binks’ inventions that went into the AMAL pot.

Here is a picture of the carburetter dismantled.


There’s not a lot to it really. Binks’ float was characteristically bell-shaped, the float needle is retained in its jet housing by the cup with four holes in it, which presses into the jet housing.

img_2701The jets are contained in the base of the mixing chamber and so are not visible here. It seems to have been a Binks feature to include a filter in the float bowl bolt. The brass hexagon in the float lid is a repair, presumably the original hexagon crumbled.

Peter wanted to know if he’d got the jets in the right places in his carb. Binks made (to my knowledge) at least three types of jet; there’s one plain type and the others are fitted with a long or short spray tube.

They are fitted with square heads to allow the convenience of being able to remove them with a clock key. Which is perhaps less simple nowadays but was probably the equivalent of a mobile phone ‘app’ in the day.

img_2737It appears that according tpo Peter’s pictures he has got it right, the jet with th elongest spray tube is located nearest to the intake (or bell-mouth) end of the carburetter. Just ot be sure I checked another Binks I have…

img_2709Similar sort of thing bit with a longer inlet pipe. This is typically found on side-valves and especially when the magneto is fitted behind the cylinder, on a side-valve obviously, the carb comes out low enough to get in the way of the magneto. Incidentally you can see here why the other carb has a repair on the hexagon…

But this carb has a secret:

img_2712Although it is made by Binks it came off a 250cc Blackburne engine from a Ransomes mower and for some reason Ransomes insisted on using their name on the carb – or maybe arranged with Binks to cast their own design of mixing chamber. But Ransomes weren’t the only ones…

This is the carb from Judy’s 1928 Scott Flying Squirrel. You can see the tombstone-shaped three bolt mounting flange exclusive to Scott and the steeply angled float chamber reflecting the angle of the inlet port on these bikes.


The Scott carb is unusual in being three jet but not to be confused with the much earlier 3-jet Binks


I have a suspicion that he third jet is to do with the carb being for a two stroke. In this case the longest of the three spray tubes is in the middle, the shorter at the intake end. Assuming it’s correct anyway…

And here’s another thing, what have we here; a couple of early brass Amals?

img_2873Nope, the one on the right is an Amal but the one on the left is an Amal-Binks, a post amalgamation variant fitted to a few bikes in the last years of the ‘twenties.

img_2867There’s the trademark filter and the two square jets and once again the longer jet is nearest the intake.


To finish, originally Binks (like Amac) used their own size markings rather than the ‘CC per minute at a given head of pressure’ utilised by Amal so don’t expect to find typical Amal sizes on Binks jets unless it is a late carb from the Amal-Binks era. Conversion charts can be found in the Radco Vintage Motorcyclists Workshop book or the reprint Amal book of Amac/Binks/B and B information available from elkpromotions.co.uk for £10 part number 23AM1.

Cheers Rick






Comment (1)

  1. Raymond Albeson

    It’s good to get more info on the pre Amal carbs and how the different features were brought together. One of the effect of that is that I can still get new AMAL floats that fit the B&B carb on the 27 Ariel.


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