Amal carbs

stuart jenkins

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Hi There,
Anyone out there put a pair of Amal Mk2 on there airhead? how do they compare to Dells? I'm thinking 38mm for my gas flowed r100.
Cheers
Stuart
 
Amals are brilliant carbs especially the mkIIs. I spoke to amal before buying a pair of Dellortos and wish I'd gone with the amals. dellortos has very little support - plenty of experts who will disappear like mist when you need real info
Give Amal a call they are a great company to deal with. None of the other companies will give you the time of day.
 
I had an Amal carburettor on a Lambretta circa 1970. Cut out in the panel for the air intake and a lovely slurp as the air was sucked in.

No use to you but thanks for bringing on a wave of nostalgia;)
 
Recycle1

Hi Stuart, I wish that I had fitted Amal carbs to my modified R100 instead of Dell-orto's which are a right pain in slow moving traffic. I would also think twice about fitting 38mm carbs, just because the bings were 38mm they are cv carbs which are far from perfect! I would suggest 32mm would be ample. Vincent in their wisdom only fitted 30mm to their v twin !
 
What are you using the bike for?

If its racing, then with sustained higher RPM's 38mm would be better, but if you want a fast road bike a smaller carb will give you much better pick up/mid range and torque where you need it.
 
Just curious -but, if the Amals are so good why haven't owners replaced their bings over the years when they come to time for shelling out on overhaul of bings?
 
B Murr said:
Just curious -but, if the Amals are so good why haven't owners replaced their bings over the years when they come to time for shelling out on overhaul of bings?
Click to expand...

Bings are very cheap to overhaul and at the end of the day are self compensating for altitude
 
Rob Farmer said:
Amals are brilliant carbs especially the mkIIs. I spoke to amal before buying a pair of Dellortos and wish I'd gone with the amals. dellortos has very little support - plenty of experts who will disappear like mist when you need real info
Give Amal a call they are a great company to deal with. None of the other companies will give you the time of day.
Click to expand...

Rob, the mk11s are good but not all Amals are great. The Concentric is awful. It will distort the barrel upon the slightest overtightening of the flange. For most of its run the body and slide were of the same material and the wear rate was truly alarming, slides jamming open was common (I suffered that on occasion on my Lightning). There were several firms at one time offering brass sleeving of the shitty slides and boring the bodies. For some years they did not even have a pilot jet, just a drilling, although pilot jets are fitted now and a premium version is offered with a slide of different material to the body. I have heard it suggested that the Concentric was built down to a price under pressure from BSA. A great shame because, as you say, Amal are good to deal with. :beerjug:
 
Current Amals have been upgraded to eliminate the old faults, but of course they are no longer cheap.
Mk 2 s are stub fitting and the Amal 28mm or 30 mm moulded rubber adapter fits airheads, and can be used to your advantage with 32mm Bings as the reduced diameter portion in the centre can be blended to the carb and intake stub, and it sets the carb a little further back too.
But they are not as forgiving as a CV carb when it comes to sizing and tune, Bings will run reasonably when quite a long way out, but one size out on almost anything on a slide carby and you are miss firing , etc.
Vincent Rapides had 1 1/16" ,or 27 mm carbs, the Black Shadow 1 1/8" or 28.6 mm, and if you do the sums that is the optimum for a higher reving but shorter stroke 1000cc Airheads.
Some folks are getting 110 hp out of race airhead motors with 32mm bings, so virtually anything you might fit is not going to restrict power, and the smaller the carb the easier it will be to tune.
FWIW my BSA B44 Victor Scrambler is a ex dealer team race bike, and it came with a well tuned 28 mm carb. I have never been able to find a setting for a 30 or 32 mm carb which runs cleanly, never mind as well as the 28 mm, although everyone tells me I should have one!
 
The old spanish made amals were a disgrace and got them an awful reputation. The new ones made by Burlen are in a different league.

The only issue I really had with the bings were the lack of options over jets there really isn't a comprehensive range available to you which drives you mad when trying to get a bike jetted correctly.

The amal website is brilliant - just look at the downloads section for tuning guides http://amalcarb.co.uk/downloads/
 
Edward said:
Rob, the mk11s are good but not all Amals are great. The Concentric is awful. It will distort the barrel upon the slightest overtightening of the flange. For most of its run the body and slide were of the same material and the wear rate was truly alarming, slides jamming open was common (I suffered that on occasion on my Lightning). There were several firms at one time offering brass sleeving of the shitty slides and boring the bodies. For some years they did not even have a pilot jet, just a drilling, although pilot jets are fitted now and a premium version is offered with a slide of different material to the body. I have heard it suggested that the Concentric was built down to a price under pressure from BSA. A great shame because, as you say, Amal are good to deal with. :beerjug:
Click to expand...

I remember in my youth being skint and trawling through buckets of knackered concentric bodies at autojumbles to find something that wasn't quite as knackered as the one I had on my bike.
 
Cheers for all the replies guys :thumb2
An engineer friend has just got a new pair for his Norton Commando and praised their build quality. I'll speak to Jim Cray to see what size he would recommend for the head work he's done.
Thanks
Stuart
 
Rob Farmer said:
I remember in my youth being skint and trawling through buckets of knackered concentric bodies at autojumbles to find something that wasn't quite as knackered as the one I had on my bike.
Click to expand...

Rob, in my youth Concentrics were years away, the current carb was a Monobloc and most of the four stroke stuff I rode then were still on separate float chamber 276s and I was always skint too. :beerjug:
 
Jim Cray likes Mikuni's, and will know how to jet them to suit his work.
And that is worth more than you probably appreciate!
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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