New Amal Premiers need filing

Status
Not open for further replies.
MexicoMike

MexicoMike

Joined
Jan 31, 2010
Messages
3,118
Country flag
Was mounting the new premiers after checking them for any swarf or debris (none) and installing different jets (250s vs the 260s that were in the carbs) and putting the needle in the top groove (leanest). This is my starting point for my stock 850 with velocity stacks at our 6400ft altitude. Both carbs were then mounted to their manifolds.

BUT, with one manifold mounted to the cylinder head, the other would not sit flush against the cylinder head intake port. The sides of the carbs interfere. It won't take much filing to eliminate the interference but I thought it was interesting that there was a problem since they are a set specifically for (per Amal) an 850 Commando.

Anyway, not a big deal but I thought I'd post this so folks wouldn't be surprised if this occurs. It's a slight misalignment at the head - less than the thickness of a business card. It is so close that I suspect normal manufacturing tolerances could result in interference on some carb sets and not others.
 
My "matched " 850 commando set had no interference issues.

But they did have a 260 main jet in one carb and a 200 in the other. Not mis-stamped. They measured 260 and 200 !
 
I might be wrong about this but IIRC the Norton “versions” should have that little corner milled off. I checked mine when I first received them and they were fine. I don’t think that is an issue with Triumphs, I don’t know about any other applications. I guess it might depend on where they come from.
Pete
 
Both of my Premiers show machined (filed) areas as delivered so it seems that Amal's idea of the necessary clearance is a tad (to put it in scientific terms) less than Norton's. :)
 
Commando
http://amalcarb.co.uk/carburettor-for-a-norton-commando-paired-with-932-29.html
New Amal Premiers need filing



http://fagengine.bigcartel.com/product/amal-premier-932-850-commando-concentric-carburetors
New Amal Premiers need filing


Standard
New Amal Premiers need filing
 
Last edited:
I wonder if it's possible to remove the casting for the tickler on the insides as well? That way you can get a straight run at the inside nuts with a thinwall socket.
 
I had to file the carbs on the inside for both my 750 and 850. I am not sure what exhausts you are running and if you have done any performance mods. I have brit euro exhausts on my 750. The head is tuned etc. My 750was too lean on the top needle notch. I am at an elevation of 6200 ft. 2 days ago i changed the needle position to the middle and now i feel much more mid range power. I am very happy i did that, its like a different bike.
 
Yep, mine look exactly like the Commando carb in Lab's pics - and so states that it's for an 850 Commando in the carb paperwork. I had to file a bit more on that already-filed flat AND also had to file the edge of the inside carb-to-manifold washer flat. The adjacent washers on the two carbs were also interfering. It took maybe 5 minutes to make the "adjustment," so it's not like it's much of a problem.
 
Not really, seems like incorrect supply. In the time AN have been selling these, this has never been an issue. If you or your local dealer buys the standard AMAL when they have no Norton ones you will need to remove the boss yourselves.
 
Madnorton said:
Not really, seems like incorrect supply. In the time AN have been selling these, this has never been an issue. If you or your local dealer buys the standard AMAL when they have no Norton ones you will need to remove the boss yourselves.
Click to expand...

But, as noted the carbs I bought ARE the Norton carbs - both per appearance and paperwork. They had the boss flattened - just not quite enough and the washers on the carbs-to manifold are just slightly proud of the edge of the carb and they also interfered. I suppose it could be s function of the original factory tolerance of the manifolds OR that of the carbs. Obviously if there was the occasional (or often?) interference issues at the factory during assembly, they would have made whatever adjustment (filing) was necessary. ;) So I suppose I just did same thing that a worker in Wolverhampton might have done in 1973! :)
 
cliffa
I,ve done it using a 12v Proxxon tool and various shaped 6mm ∅ x 3mm shank rotary burrs, so a 1/4" drive socket easily fits the inner nuts.
The casting bosses are solid and you can remove enough to have plenty of clearance, be aware that cuttings from the carbide burrs are pretty sharp and the carb material tough.

I,ve also removed the ticklers, filled the holes with JB Weld then cut away the casting bosses and blended them into the body and idle screw castings, but it,s only cosmetic for a cleaner appearance.

My Mk3 specific Premier pair (from AN) fitted perfectly as supplied and the inner flanges mentioned by MexicoMike looked like they were milled for about 1mm fitted clearance.
 
Last edited by a moderator:
Hi KiwiNeill,
Thanks very much, that's exactly what I needed to know as I wasn't sure if those were hollow in the centre.

Out of interest, don't you need the ticklers to start your bike?


Cheers,

cliffa.
 
cliffa
glad to help, cold starts on full choke don,t need ticklers on my e start bike. Gets marginal at low and sub zero temps but just requires a little more cranking over with the starter.
Probably a big pain with a kick start but mine removed completely from gearbox.
I wasn,t keen on the ticklers leaking fuel on the starter motor.
 
johnm said:
My "matched " 850 commando set had no interference issues.

But they did have a 260 main jet in one carb and a 200 in the other. Not mis-stamped. They measured 260 and 200 !
Click to expand...
Hi John, did you mean they were both stamped 260 and only one was measured as 260.......? the other is 200 !! not good , I know we must check them thoroughly before using , but ..........
 
marinatlas said:
Hi John, did you mean they were both stamped 260 and only one was measured as 260.......? the other is 200 !! not good , I know we must check them thoroughly before using , but ..........
Click to expand...

Typical company, can’t get the staff now days !:(
 
Status
Not open for further replies.
Back
Top