Amal “Premium?”

Do they leak and spit fuel at shaky idle at a stoplight on a Commando? I'm struggling with opting for 30mm Premiers or 34 1 Mikuni. I've had great luck with them and no leaks

wildbill56 said:

Do they leak and spit fuel at shaky idle at a stoplight on a Commando? I'm struggling with opting for 30mm Premiers or 34 1 Mikuni. I've had great luck with them and no leaks

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I would go for the premiers. I've just finished a complete rebuild on a friends 850, to which I fitted a pair of 932s. It idles & runs like a modern bike. The latest Concentrics are very nicely made, have aluminium bodies, & as a bonus are lighter then the old ones. I also fitted a set of 627s to a Trident a few years ago & they were spot on. A pair of 930s has just arrived from Surrey Cycles for my '68 Commando.

Martyn.

wildbill56 said:

Do they leak and spit fuel at shaky idle at a stoplight on a Commando? I'm struggling with opting for 30mm Premiers or 34 1 Mikuni. I've had great luck with them and no leaks

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No the new Amal Mk1's shouldn't. Mine are fine with no issues. 932 on an 850 1974.

The Premieres on the Vin sure don't do that, but then the old time MK1s on the 850 and 920 also work fine, good idle and throttle response, no leaks.

Glen

Matchless said:

I would go for the premiers. I've just finished a complete rebuild on a friends 850, to which I fitted a pair of 932s. It idles & runs like a modern bike. The latest Concentrics are very nicely made, have aluminium bodies, & as a bonus are lighter then the old ones. I also fitted a set of 627s to a Trident a few years ago & they were spot on. A pair of 930s has just arrived from Surrey Cycles for my '68 Commando.

Martyn.

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thnx.....I recall the worn slides on commandos spitting and leaking at stoplights......I'm doing a 1970 750. I think I'll try the Premiers

Thomasa said:

As regards pre-68 pilot jets, I've had to deal with far too many post-67 Amals with plugged pilot bushes. Amalitis we called it. Sometimes they can be cleaned with the bristle from a wire brush or tiny drill bit, carb cleaner and compressed air and sometimes not. Customers were not happy with the "not" scenario and this was way before ethanol gas. Now it's worse. I've worked on half a dozen plugged pilot jets just this spring (not Amals). As a fall-back procedure, I have converted carbs back to the old pilot jet successfully with the bike starting and running well, assuming the rest of the carb and tune was properly dialed in. With carbs that have good slides and bores, I'm reluctant to scrap them because of plugged pilot bushes. It's far less expensive to retrofit than buying new carbs. The one stumbling problem I've had with the screw-in jets turned out to be something else and that bike now runs just fine. Undoubtedly, there are scenarios where the screw-in jets cause difficulties but the retro-remedy is easy to do and if it doesn't work out one doesn't have a huge investment in time or materials.

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Thomasa,
Surely you mean ANALITIS!!

Matchless said:

The latest Concentrics are very nicely made, have aluminium bodies, & as a bonus are lighter then the old ones.

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Aluminium body Concentric Mk1 Premier is an option for the 600 series only, according to manufacturer Burlen. 900 and 1000 series Concentric Mk1 Premier carbs are still made of Zamak (a Zn-Al-Mg-Cu alloy).

- Knut

Not so! Both 600 & 900 series are aluminium & have been for a while now. The 1000 series are not available & probably never will be, as when they were still being made they were only fitted to a tiny handful of bikes. When ordering 900 type be certain to specify aluminium, as otherwise you may receive older stock. I've had two pairs recently, both from Michael at Surrey Cycles, both ally bodied. As I have said before, they are beautifully made with hard anodised slides & accurately machined bodies. If the old Brit bike industry had been run by engineers & not accountants, they might have been better from the start.

It was run by engineers until they needed bailing out. (I'm not an accountant!)

mdt-son said:

Aluminium body Concentric Mk1 Premier is an option for the 600 series only, according to manufacturer Burlen. 900 and 1000 series Concentric Mk1 Premier carbs are still made of Zamak (a Zn-Al-Mg-Cu alloy).

- Knut

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Not true - no more Zinc carbs, the 600- and 900- series are all Aluminum now and have been for months. I don't know bout the 1000-series or MKII carbs.

marshg246 said:

Not true - no more Zinc carbs, the 600- and 900- series are all Aluminum now and have been for months. I don't know bout the 1000-series or MKII carbs.

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Hi Greg,
I've been corrected already, but thank you anyway. Strangely, Burlen's web page does not mention this, nor does AN. At least Burlen need to get their act together!
I sent them a query several days ago, alas, no reply.

- Knut

mdt-son said:

Hi Greg,
I've been corrected already, but thank you anyway. Strangely, Burlen's web page does not mention this, nor does AN. At least Burlen need to get their act together!
I sent them a query several days ago, alas, no reply.

- Knut

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Sorry, missed that.

Since I am a dealer, I knew about it before most. The good news is that after many years of struggle, the switch to AL is letting them finally catch up. It will still be a while before they have carbs in stock to order direct - they still have LOTs of dealer back orders to fill.

The other good news is that the AL carbs are being tested before packaging. I've used/sold many AL sets and have not heard of or seen anything wrong with any of them.

It probably matters where the carburettors are made. I use two 34mm Mk2 Amals which are very similar to VM Mikunis. What I like about them is they are shiny and bright silver. Which to me says the alunimium they are made from does not contain much zinc. I use methanol fuel, which in carbs made from high zinc material can form a white slime which can block jets. Most fuels these days probably contain ethanol, which can do similar if you don't drain your carbs after you have used your bike.
When I had my T250 Suzuki, it was on methanol with MIkuni carbs. I had a seizure due to the white slime which locked the back wheel at high speed. So I decided to drill the drain screws in the bottoms of the bowls. I found they were already drilled, All I needed to do was slacken them after riding the bike, and remember to tighten them again the next time. WIth my Amals, I remove the jet covers. and put them on the shelf.
The aluminiums of the Aluninium Development Council vary in alloying elements and this is indicated by their number series The series which contains magnesium is used for marine purposes because it is corrosion resistant. If your carbs are made in the UK, the manufacturers would probably be more on top of their game. The series which contains copper cannot be anodised. I think it is the 4000 series. I think the 5000series is the one with magnesium. In the old days, the country with the worst appreciation of metallurgy was Italy. But they were the best at casting technology. I wonder about the Japanese. I think they just work within the constraints of what they have. I have never heard of them doing materials development. I think they just use American technology and do it better. But I cannot read Japanese.

Don’t know if this adds to the thread but I just received my new Amal carbs from Greg there nice carbs and made in England came with correct jets and choke cable plugs , will ASAP .