Re-sleeve or Replace Amals

This winter I need to fix a small carb issue on my Mark lll Commando. The bike runs very well but one carb slide has a tendency to stick for a short time, and periodically.

I don't know whether to re-sleeve the Amals or replace them with new. Aside from re-sleeving being less expensive, is it better to replace?
Thanks,
Stephen

The build quality of new Amals isn't as good as it was. People here have reported band new carbs being bad. My recommendation is to sleeve the old ones.

I'm in the resleeve camp - higher tolerances, differing materials, cheaper. Should been the first thing I did - instead of the last!
I can vouch for Bruce Chessel, nice guy and good work.

Bruce has done some monoblocs for me, great work.

Lund's (new owner) did a set of concentrics with good results, monoblocs remain to be seen (haven't started the bike yet)

Had mine re-sleeved many years ago and never a problem sense other than the occasional tuneup. Buy new and you'll still need to re-sleeve or replace later! :wink:

The latest Amals, made in the last couple of years using the new moulds, are at least as good as the original Birmingham Amals. Fitted with the new slides, floats and needle valves they are better. I have fitted three sets recently to T140s and I'm thinking of ditching the monoblocs on my 650 because these Concentrics have worked so well straight out of the box.

My resleeved 930s have done over 40,000 miles and the only problem was self inflicted. Be very carefull (don't lay the carb body on the bench and try to loosen the inlet stub nuts) taking the carbs apart.

Greg

If you re-sleeve amals they are still Amals.

Mikuni, Del Orto and Keihin are lightyears ahead and don't need re-sleeving, work better and stay in tune. Its like the difference between points and electonic ignition.

More info at www.jsmotorsport.com

I bought new stock Amals two years ago. They have performed perfectly ever since including a 1500 mile road trip. I wonder how many people have fallen for the dated and incorrect mantra that Amals are hard to set up and unreliable whithout ever having worked with them. The most common path I hear is a new Commando owner buys a worn out bike and decides right away to start hanging new parts on it so it will be reliable. That's not really an objective assesment of the original componants performance. A worn out Mikuni will be as bad as a worn out Amal. Maybe worse. 35 years later Amal parts and carbs are available all over the place. I wonder if anybody is running a 35 year old Mikuni and having an easy time buying parts.

I too fought Amals for years and though about replacing them with a single Mikuni. But now there's so much information on the web to properly set up Amals! I can now say the only more efficient fueling system I've had is fuel injection! My re-sleeved Amal Norton 850 starts every time with one kick, idles at stop lights at 800 RPM, no surging at any RPM, and pulls cleanly in any gear or RPM. Just amazes me how I hated and I fought Amals for 20 plus years before getting them right! :lol:

I had run a single 34 Mikuni for the past 12 years.

I have also put 50,000 miles on Commandos with Amals since 1970.

My bike is now the proud owner of a set of Jim's 32mm flat slides.

Today, I rode over 30 miles in altitudes ranging from 5000 to close to 8000 feet here in New Mexico.

The carbs are spectacular. Period. As one would expect of a single Mikuni or well set up Amals, they start with one kick and idle smoothly at 700rpm.

But it is off idle when the difference is felt. They are far, far superior to a single Mikuni. Period.

The difference between the flat slides and two Amals is still very noticeable. The flat slides feel more precise in their delivery, and feel stronger, more quickly responsive.

For $445 delivered to my door, complete with lower cables, rubber and aluminum manifolds, air filters, and fuel line, I can't think of a better set of carbs for any money for a Commando.

What he said.

Jim has a great product. Great support too. Happy me.

I think that Brit bikes ought to have Brit parts on them. AND, I believe that the concentrics are very good carbs - especially with changes in altitude. Their circuit design and flow are better than a VM Mikuni and the smoothbore monoblocs are even better than the concentrics. There were Amal engineers, now long dead, who really knew what they were doing.

So, it was hard for me to walk away from the Amals but the Keihins have a great reputation and frankly, I've been irritated for 30 years with the bean counters at Amal who decided to cheapen the product by selling a zinc slide in a zinc body. Now, after 35 years of wrecking the company's reputation with that zinc slide, Amal finally decides to sell an anodized aluminum or a hard chromed brass slide for your Amal, well that's great. Long overdue.

Now, they sell NEW Amals too. That's great too, and at a nice price BUT not with a proper chrome or aluminum slide. NOOO, you can buy a new set of Amals but if you want slides that will actually last more than a few thousand miles, well, you have to buy them separately ?!??!??!

And, while I'm ranting, what's up with the MK2s? or the smooth bore MK2s? Why did those great carbs go away? Sheesh.

Burlen Fuel Systems have owned Amal for about the last five years and they are the people who are finally developing and improving Amal carbs.

The carbs I've had from them come with the new parts installed on request. You pay more but I guess there's a cost to development.

I vote for re-sleeving over new Amals. A re-sleeved Amal is a more durable piece than an original. And try Burlen's level-adjustable floats. Much easier than banging around on the float needle seat to get proper fuel level.

I got some new parts from Burlen, stay-up floats (and they are adjustable on the float, not banging on the seat), gasket sets and viton tipped needle. Seem to be fine, set the float at .08 below bowl? Is that right? My old plastic floats were flat up against the top of the bowls. Haven't started yet.

Dave
69S

According to Burlen, the floats should be set just above and parallel to the top of the float bowl. I set mine up with the two bowls and the fuel lines assembled and dripped water into the lines until no more would go and observed the float heights and adjusted until at the recommended height.

Danno,
I am very confused about the Burlen instructions. What I read is they say the original settings of the concentric float at parallel to the top of the bowl resulted in a rich mixture getting into the carb and then they suggest a 0.08 below the top of the bowl for the back of the float. Check out the Amal page, it is all there, at least that's the way I read it. Anyhow, I'll be trying to start up my 69 up this Thursday or Friday for the first time in maybe 18 years and I'll let y'all know if it works. I may have to adjust my new stay-up floats to get the gas in it. If someone else reads the Amal instructions different, I would like to know. Here is what they say:

1966-1972

The original float chambers were fitted from 1966 to 1972 with the drain plug being introduced in 1970. The depth of the needle valve seating from the top edge of the float bowl to the floor of the seating measures 0.588”. Other distinguishing features are:

1. The top of the seat sits flush with the surrounding alloy.
2. Pressure on the float tags to hold the needle valve shut will cause the float to protrude above the top of the bowl by an angle of approximately 5 degrees.


This seating depth produces a fuel level very near the top end of the correct range, and small variations in float weight, float tag position and float needle wear can produce a carburetter that runs excessively rich and in extreme cases cause the floats to foul the top of the float chamber. These float chambers also have shallower float spindle slots than later versions.

To improve the fuel level in these bowls it is necessary to either adjust the needle seat to achieve a depth of around 0.565” or adjust the tangs of the Stayup float so that the far edge of the float sits 0.080” below the top of the float bowl. The tangs can be easily adjusted by clamping the float in a vice up to the spindle hooks and tapping the body of the float gently in the direction required until the required level is achieved.

Dave
69S