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Early Concentrics Question
#788793 11/01/19 4:27 pm
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mrcarb Offline OP
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My 69 Lightning has early Concentric AMAL carbs. Is it possible that these originally came on the bike? Just curious because I thought that AMAL had changed the design of their carbs at this point in time.

Thank you in advance for your answers

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Re: Early Concentrics Question
mrcarb #788796 11/01/19 4:39 pm
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The 2 stroke ones, or whatever we might call them. I have a 69 Firebird that had them from new.

Re: Early Concentrics Question
mrcarb #788800 11/01/19 4:50 pm
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very possible, tell tale sign will be either a nub instead of the protruding large ticker button, most importantly is on the casting would be a tiny (1mm?) hole, the ticklers were upgradeable but the casting would have still had the drilling to let the fuel out, as opposed to it flowing all the way up the tickler button as later manufactured ones are.

red line pointing to bleed hole


HTH

Attached Files amal tickler2.JPGamal tickler.JPG

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68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Early Concentrics Question
mrcarb #788802 11/01/19 5:24 pm
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I researched Concentrics when I was doing a '67 Spitfire years ago. Story I got was '67 Spitfire was first use of Concentrics (bodies were numbered 1 & 2 I believe). Everyone else could get them in '68. Makes sense your '69 would have them.


Laurence Luce
Re: Early Concentrics Question
mrcarb #788808 11/01/19 6:17 pm
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Re: Early Concentrics Question
mrcarb #788809 11/01/19 6:18 pm
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As far as I know the updated version was supposedly fitted from the start of the 69 season on Triumphs, but that needn't necessarily be strictly true.
All the 69 Triumphs I've worked had the newer version, but it's conceivable that the old Concentrics were fitted at the start of production for that year.
The bigger tickler came later, even the early 750 twins had the small one, but I don't know when they changed over.

Triumph switched to Concentrics sometime during the 67 season.

Re: Early Concentrics Question
mrcarb #788833 11/01/19 10:50 pm
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As I remember it, the first Concentrics appeared on the '67 BSA 441 Victors.

Re: Early Concentrics Question
mrcarb #788840 11/01/19 11:33 pm
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Bacon's Singles Resto bools lists the 67 B44VE with the 930/1 carb. The first BSA twin for Bacon Twin Resto book was the 67 A65S M111 with a 932/1 and a 932/2 carb

Gordo


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Re: Early Concentrics Question
mrcarb #788862 11/02/19 2:37 am
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Nae float bowl drain. shite.


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Re: Early Concentrics Question
mrcarb #788869 11/02/19 4:37 am
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Don't know when they added drains on the float bowls. Probably after the first time they left the bike out in the rain. laughing
A big part of the upgrade to early Concentrics is needle jets with the cross drilled holes.
When did they switch to the pressed in idle jets?
AFAIK extended ticklers are an add-on option. I've never been blessed to buy a bike which had them installed by the PO.


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Re: Early Concentrics Question
mrcarb #788875 11/02/19 8:00 am
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Concentric carbs were fitted to multiple bikes in 67 including bantams whilst other models retained the monoblock carb. Probably more to do with a different size carb was needed for that model year than something was just so special that they had to switch??? Maybe.

I think drain bowls changed in 69 along with the additional “4 stroke carb” pressed in bush, needle jet, needle jet holder, needle.

The 67/68 setup stayed almost the same (the only change being the float bowl and pilot jet) for the 2 stroke carbs.

Last edited by Allan Gill; 11/02/19 8:01 am.

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68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Early Concentrics Question
DavidP #788877 11/02/19 9:09 am
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Originally Posted by DavidP
Don't know when they added drains on the float bowls. Probably after the first time they left the bike out in the rain. laughing
A big part of the upgrade to early Concentrics is needle jets with the cross drilled holes.
When did they switch to the pressed in idle jets?
AFAIK extended ticklers are an add-on option. I've never been blessed to buy a bike which had them installed by the PO.

The first Concentrics were troublesome and prone to idling issues, unreliable idling and cutting out at intersections, rough transition from idle and that sort of thing.
The differences in the new version included relocating the idle jet and cross drilling the needle jet. The float bowl drain has been mentioned. Other differences were a longer jet holder (the piece the jets screw in to) and a longer jet needle. It's true that the extended ticklers were an option to start with, and I can't say if any bike were fitted with these originally.
I have a number of the first style carbs in good condition sitting on the shelf doing nothing. I'm going to try to fit a premier type idle jet to them and see if it works.

Re: Early Concentrics Question
mrcarb #788892 11/02/19 11:56 am
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I think the drains began with the 1971 models.

My old but original condition '70 TR6R doesn't have one , and back in 1970 my then-new T100C didn't have one either

Re: Early Concentrics Question
mrcarb #788984 11/03/19 2:34 am
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That 69 Firebird had those carbs on it almost 35 years. Bike was ridden at least a few times almost every year. But I always hated the carbs and after the internet and britbike.com I finally learned why.


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