Forum

[Pathfinder856]

Good Morning Guys

I am thinking about. Buying the Amal Concentric conversion Kit from our hosts.
My main reasons are the improvement in performance and better running , and mainly because it looks better fitted to the bullet than the standard Mikcarb.

Does anyone here have this carb, is it a worthwhile conversion?
Does the bike run any better, does it start easily ?

I have one of the Watsonian built 500 Trials bullets, four speed Kick start model, it is standard , ie it has a Pancake style filter as fitted to the Amal carbs and has a slightly freer flowing silencer.

I look forward to hearing your views on this carb and any recommendations

Regards

Richard

[Edward]

Hi Pathfinder, in my opinion you will be wasting your money. You will almost certainly get more performence but only when the Concentric is passing more gas than the Micarb at which point you engine will be revving harder than is good for it. Below this point the Micarb will likely perform better as the speed of the gas passing through it will be higher. The Concentric is far from the best carb available, the body is easy to distort by overtightening the flange nuts just a little too much. They wear quicky. Also you will be wasting fuel every time you tickle it at startup.
I have suffered these nasty Amals since their introduction on British bikes in the sixites and only retain them for the sake of originality. If I wanted to use my BSA Lightning daily I would fit Mikuni.
Amal have made good quality carbs but the Concentric is not one of them.

[PeteF]

I'm with Edward here - nothing wrong with the Micarb.

[Pathfinder856]

I agree that the Mikuni is a very good carb and a lot better than the Amal.
I just read an article on amals and it mentioned the wear of the slides, and bodies.
Apparently this was. Due to the use of a Zinc Alloy, I believed that the new ones are. Made from an aluminium Alloy, less prone to wear and warping.

When I mentioned performance I really mean, easy starting, smother running and slightly freer flowing performance as obviously the standard carb is set up to pass stringent emissions regulations.

I do think that the Amal looks the part on the. Enfields

Regards

Rich

[Pathfinder856]

Does anyone have anything good to say about this carb conversion ?

[The rider formaly known as Lone Rider]

There is a new version of the Mk1 Concentric called the Premier. This version has a modified slide that is not prone to ware, and it has a removable idle jet, instead of that stupid idea of having a fixed bush for a jet.

A very tuneable carb now. As for the slide locking up; just do not swing on the fixing nuts when tightening up.

I have had the old MK1 on my bike for four or five years. The only criticism would be the fixed bush jetting. I overcame that problem by drilling out the idle blanking plug and running a drill down the pilot bush to increase the size.

Works a treat!

[Pathfinder856]

Hi

Thanks for your reply, I read an Article in a classic bike magazine the other day and it was all about Amal and mentioned the new Carb.
I am not sure if the one that our Hosts sell is this carb though, it is listed as an Amal Concentric Mk1
I was hoping to have some more replies from fellow enthusiasts that had fitted them to their Classic engined Indian Built Bullets like mine!
Who could give me their opinions on how well it works.

I think that it looks great fitted to the Bullets and want to fit one, but just want to know is it an improvement ?
I have had several Armstrong MT 500's two had Amal concentric carbs, one ran terribly, the other a fully rebuilt bike with a new carb ran great !!
I had two others that had Delorto carbs fitted, they drank fuel !!!
And one with a Mikuni
That ran very well, and was probably the best carb.

However if I was building a 612cc fire breather then I would only fit a Mikuni, but I may consider a 535 alloy barrel and high comp piston and a couple of other Minor mods, but I would rather the look of the Amal as I think it suits the bike and is more in keeping with the styling .

[Thack]

The perennial problem with the Mk1 Concentric is a flat spot just off idle, especially noticeable when opening the throttle slowly.



The Micarb is a good carburettor - better than the Mk1 Concentric. However, replacement jets and slides are easier to come by for the Amal, which means you will find it easier to tune to your satisfaction.



I've had loads of bikes with the Mk1 Concentric, and I think they are the worst motorcycle carbs I've experienced. However, with some luck you should be able to set one up to give more performance than the standard Micarb (because the Micarb is set up to run weak).
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Most installations (but not all) suffer that flat spot, so be prepared for it, and some bogging if you snap the throttle wide open. Also be prepared for a worsening of the fuel consumption.



From a technical point of view, there is no good reason to choose an Amal above any other. However, from a practicality point of view, they are very cheap and tuning parts are easy to come by. And if the look is important, then that must count for most of the argument.

[Pathfinder856]

I see, that is a shame about the flat spot, I do not really want that either.
Has anyone else experienced this ?

[Chris Tindal]

Don't know about the concentric but the monobloc is a good carb and looks superb on a bullet. I have a 389 on my iron 500 with bellmouth and free flowing pipe and it goes really well.