BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorThe Bonneville ShopBritBike Sponsor
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments.
Buy BritBike staff a coffee
Buy BritBike's staff a coffeeStill here since 1996 serving BritBike enthusiasts..
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Member Spotlight
dig
dig
new zealand
Posts: 78
Joined: June 2003
Show All Member Profiles 
Newest Members
Chris French, Mel PinX, Digital Expressions, johnjorgensen, Ray Byrne
10917 Registered Users
Top Posters(30 Days)
franko 84
quinten 70
Popular Topics(Views)
1,051,483 mail-order LSR
a word from..
Forum Statistics
Forums35
Topics68,093
Posts683,447
Members10,917
Most Online14,755
May 5th, 2019
Who's Online Now
85 registered members (Adam M.), 498 guests, and 1,023 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Early Concentrics Question #788793 11/01/19 4:27 pm
Joined: Jun 2016
Posts: 101
M
mrcarb Offline OP
BritBike Forum member
OP Offline
BritBike Forum member
M
Joined: Jun 2016
Posts: 101
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

Support Your #1 BritBike Forum!

Check out British motorcycles for sale:
British Motorcycles on e-Bay UK
British motorcycles on e-Bay North America
Re: Early Concentrics Question [Re: mrcarb] #788796 11/01/19 4:39 pm
Joined: Dec 2002
Posts: 3,202
L
leon bee Offline
BritBike Forum member
Offline
BritBike Forum member
L
Joined: Dec 2002
Posts: 3,202
The 2 stroke ones, or whatever we might call them. I have a 69 Firebird that had them from new.

Re: Early Concentrics Question [Re: mrcarb] #788800 11/01/19 4:50 pm
Joined: May 2013
Posts: 5,951
Allan Gill Online Happy
BritBike Forum member
Online Happy
BritBike Forum member
Joined: May 2013
Posts: 5,951
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

beerchug
Re: Early Concentrics Question [Re: mrcarb] #788802 11/01/19 5:24 pm
Joined: Jun 2017
Posts: 58
S
slow learner Online Content
BritBike Forum member
Online Content
BritBike Forum member
S
Joined: Jun 2017
Posts: 58
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 [Re: mrcarb] #788808 11/01/19 6:17 pm
Joined: Dec 2002
Posts: 562
M
MarcB Online Content
BritBike Forum member
Online Content
BritBike Forum member
M
Joined: Dec 2002
Posts: 562

Re: Early Concentrics Question [Re: mrcarb] #788809 11/01/19 6:18 pm
Joined: Sep 2008
Posts: 1,205
S
Stein Roger Online Content
BritBike Forum member
Online Content
BritBike Forum member
S
Joined: Sep 2008
Posts: 1,205
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 [Re: mrcarb] #788833 11/01/19 10:50 pm
Joined: Oct 2006
Posts: 3,256
I
Irish Swede Online Content
BritBike Forum member
Online Content
BritBike Forum member
I
Joined: Oct 2006
Posts: 3,256
As I remember it, the first Concentrics appeared on the '67 BSA 441 Victors.

Re: Early Concentrics Question [Re: mrcarb] #788840 11/01/19 11:33 pm
Joined: Sep 2001
Posts: 3,032
Gordo in Comox Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Sep 2001
Posts: 3,032
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


The roadside repairs make for the best post ride stories.
Re: Early Concentrics Question [Re: mrcarb] #788862 11/02/19 2:37 am
Joined: Aug 2001
Posts: 4,747
gavin eisler Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Aug 2001
Posts: 4,747
Nae float bowl drain. shite.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: Early Concentrics Question [Re: mrcarb] #788869 11/02/19 4:37 am
Joined: Oct 2008
Posts: 5,753
DavidP Online Content
BritBike Forum member
Online Content
BritBike Forum member
Joined: Oct 2008
Posts: 5,753
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.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
Re: Early Concentrics Question [Re: mrcarb] #788875 11/02/19 8:00 am
Joined: May 2013
Posts: 5,951
Allan Gill Online Happy
BritBike Forum member
Online Happy
BritBike Forum member
Joined: May 2013
Posts: 5,951
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.

beerchug
Re: Early Concentrics Question [Re: DavidP] #788877 11/02/19 9:09 am
Joined: Sep 2008
Posts: 1,205
S
Stein Roger Online Content
BritBike Forum member
Online Content
BritBike Forum member
S
Joined: Sep 2008
Posts: 1,205
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 [Re: mrcarb] #788892 11/02/19 11:56 am
Joined: Oct 2006
Posts: 3,256
I
Irish Swede Online Content
BritBike Forum member
Online Content
BritBike Forum member
I
Joined: Oct 2006
Posts: 3,256
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 [Re: mrcarb] #788984 11/03/19 2:34 am
Joined: Dec 2002
Posts: 3,202
L
leon bee Offline
BritBike Forum member
Offline
BritBike Forum member
L
Joined: Dec 2002
Posts: 3,202
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.


Moderated by  Allan Gill, Jon W. Whitley 

Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.3