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Straightening Amal Concentric (a la John Healy) #219624
10/19/08 10:37 pm
10/19/08 10:37 pm
Joined: Aug 2006
Posts: 84
Fort Campbell, KY
Ken Wainwright Offline OP
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Ken Wainwright  Offline OP
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Joined: Aug 2006
Posts: 84
Fort Campbell, KY
John, I wonder if you could post a link to your article about straightening out a warped AMAL Concentric (referred to this weekend at Barber, and in a post about straightening a head). From what I understand, take a stiff metal plate and drill a bolt hole through it, place the warped AMAL against it, insert a metal tube/pipe with the same drilled hole, and then insert the bolt though the plate and then through the pipe...let it sit and straighten out. Is that correct, or did I miss something?

Thanks

Ken

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Re: Straightening Amal Concentric (a la John Healy) [Re: Ken Wainwright] #219785
10/20/08 11:35 pm
10/20/08 11:35 pm
Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J

Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
We have been straightening AMAL carb flanges for some time now (see a 1994 letter from Mike Gaylord below).















In 1994 I received a letter Mike Gaylord who wanted me to publish it in Vintage Bike:

It is as follows:
Mike Gaylord
5417 34th Ave SE
Lacey, WA 98503

John Healy, editor
T.I.O.C.
P. O. Box 6676
Hollister (sic) MA
01746-6676

Dear John; Nov. 9, 1994

I cringe at the advice appearing recently in a popular
motorcycle magazine. Perhaps if you publish this letter
it will dispel the faulty practice.

The author prescribed the method of flattening a bowed
flange by, "Rubbing it on emery over a surface plate".
Its the same advice advanced by, "Experts", for years,
but now, stop and think. "That: method was employed by
Primitive Pete in the stone age, whose only concern was
to get the thing going well enough to reach the hunting
and gathering grounds.

Is "That" method appropriate for you today? No. Not if if
you are interested in getting the job done right.

Today we have better tools than old Pete's stone ax, to
deal with the job at hand. Having personally straightened
thousands of Amals, I feel qualified to discuss the cause
of bowed flanges, the proper cure, and the injurious
result of crude methods.

We note at our facilities, that the only flanges not
requiring straightening during reconditioning, are off low
miles Nortons and BSA triples. At least one assembler at
BSA had the "Touch", and understood that it is not necessary
to chin yourself on the mounting nuts.

Norton mounts their carbs straight to a manifold and the
flanges stay flatter than the flanges of carbs that are
mounted against insulator blocks, as is/was the practice of
most British makes.

The insulator block is of fiberous material that will crush
under excessive pressure. An unskilled mechanic will install
a carburetor with crushing pressure almost every time.
The crushing of the insulator allows the flange to bow.
As the flange changes shape, stress is created in the
casting, causing the walls of the mixing chamber to go
out of round. In severe cases, the slide used therein will
bind and stick... a very dangerous situation!

Flycutting or lapping the flange does not correct the
distortion in the mixing chamber, but does spoil the
casting by thinning and weakening the flange, while
allowing the distortion to remain.

Internal distortion is corrected and the flanges are
straightened with special fixtures. The process is the
first and most important step in our reconditioning
sequence, as it restored the integrity of the casting
and retains the original strength.

If you are dealing with a bent carburetor body, have
it straightened. Never lap or flycut a flange, as metal
removal methods do irreversible damage.

Also, an insulator block that has been crushed should
not be reused. the block may appear flat, but it will be
spongy instead of firm in the falnge area, and will no
longer afford a carburetor flange the necesary support
and a straight flange can easily be ruined by such an
insulator.

Very truly yours

Mike Gaylord


Last edited by John Healy; 10/21/08 12:29 pm.

Re: Straightening Amal Concentric (a la John Healy) [Re: John Healy] #219851
10/21/08 12:41 pm
10/21/08 12:41 pm
Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J

Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
bump


Re: Straightening Amal Concentric (a la John Healy) [Re: John Healy] #219887
10/21/08 3:16 pm
10/21/08 3:16 pm
Joined: Apr 2005
Posts: 1,686
Mississauga, Ontario.
A
Adam M. Offline
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Adam M.  Offline
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A

Joined: Apr 2005
Posts: 1,686
Mississauga, Ontario.
Isn't it possible to "stick it" somewhere on the board for everybody to see and read ?

Adam M.

Re: Straightening Amal Concentric (a la John Healy) [Re: Adam M.] #219892
10/21/08 3:41 pm
10/21/08 3:41 pm
Joined: Dec 2006
Posts: 4,037
Massachusetts, U.S.A.
B
btour Offline
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btour  Offline
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B

Joined: Dec 2006
Posts: 4,037
Massachusetts, U.S.A.
Hi John,

What is the feeler gauge doing there?


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
Re: Straightening Amal Concentric (a la John Healy) [Re: btour] #219939
10/21/08 7:35 pm
10/21/08 7:35 pm
Joined: Mar 2005
Posts: 430
Nashville, Tn.
T
T. Sharp Offline
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T. Sharp  Offline
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T

Joined: Mar 2005
Posts: 430
Nashville, Tn.
Ken, sorry that you didn't know that I always bring a John Healy jig to the track to straighten 900 series bodies.
I was on the bottom tier at Barbers.
The jig uses a closely machined solid cylinder, not a simple tube!
The thing works in an instant, and I've only found one carb that was so screwed up that I couldn't insert the cylinder into.
I copied Johns design from a photo, and it works beautifully.

Re: Straightening Amal Concentric (a la John Healy) [Re: T. Sharp] #219940
10/21/08 7:42 pm
10/21/08 7:42 pm
Joined: Jun 2006
Posts: 804
Halifax, Butt end of Europe
andrewinpopayan Offline
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andrewinpopayan  Offline
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Posts: 804
Halifax, Butt end of Europe
I figure the feeler is there to "overbend" it by a fraction, when the comprssive force is removed from the flange the natural springiness of the metal will cause it to return to "slightly less bowed" rather than flat. You gotta bend it back plus a bit more to allow it to return to flat.


99% of carb problems are electrical.

1959 3TA

BMW R1150 Oilhead
Re: Straightening Amal Concentric (a la John Healy) [Re: andrewinpopayan] #219961
10/21/08 10:57 pm
10/21/08 10:57 pm
Joined: Aug 2001
Posts: 7,209
Vermont
Jon W. Whitley Offline

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Jon W. Whitley  Offline

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This is a great wealth of info for the home restorer enthusiast, but I am going to need a spec drawing with a few more pics to visualize this!

beerchug


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project

Re: Straightening Amal Concentric (a la John Healy) [Re: Jon W. Whitley] #220842
10/27/08 3:16 pm
10/27/08 3:16 pm
Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J

Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
Jon: Get out your back issues of Vintage Bike. We covered this in detail.
John


Re: Straightening Amal Concentric (a la John Healy) [Re: John Healy] #220849
10/27/08 3:51 pm
10/27/08 3:51 pm
Joined: Nov 2005
Posts: 7,491
Back on the mainland!
JubeePrince Offline

Life member
JubeePrince  Offline

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Joined: Nov 2005
Posts: 7,491
Back on the mainland!
Originally Posted By: John Healy
Jon: Get out your back issues of Vintage Bike. We covered this in detail.


Fall 2006 (Vol.2004-3)....... bigt

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Straightening Amal Concentric (a la John Healy) [Re: JubeePrince] #220858
10/27/08 5:11 pm
10/27/08 5:11 pm
Joined: Aug 2001
Posts: 7,209
Vermont
Jon W. Whitley Offline

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Jon W. Whitley  Offline

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Posts: 7,209
Vermont
Thanks bigt

beerchug


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project

Re: Straightening Amal Concentric (a la John Healy) [Re: Jon W. Whitley] #220880
10/27/08 7:19 pm
10/27/08 7:19 pm
Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J

Joined: Mar 2005
Posts: 10,220
Boston, Massachusetts
Gee Steve, I wish I still had a memory ;-).

Vintage Bill, editor at large, is preparing a searchable Word document that will let you look up topics from the last 20 years of Vintage Bike.
John


Re: Straightening Amal Concentric (a la John Healy) [Re: John Healy] #220886
10/27/08 8:06 pm
10/27/08 8:06 pm
Joined: Aug 2005
Posts: 57
Florida
C
camshaft1 Offline
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C

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Posts: 57
Florida
And... where can I buy this "straightener" gizmo??
Thanks,
JC

Re: Straightening Amal Concentric (a la John Healy) [Re: camshaft1] #220926
10/28/08 12:15 am
10/28/08 12:15 am
Joined: Feb 2007
Posts: 110
Orlando, FL
Tiger73 Offline
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Tiger73  Offline
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Joined: Feb 2007
Posts: 110
Orlando, FL
John,
Your article about straightening the AMAL carb was quite a tease. It did'nt tell us how the straightening was accomplished or what the apparatus consisted of so we could at least attempt to make one for ourselves. You made it seem that it was a heavily guarded secret but since it was published in an earlier issue of Vintage Bike which not all of us have access to, I can't believe this is true.

I think we would all really appreciate it if you could somehow find the time to re-publish the article on this site or at least explain what is done and include some pictures or drawings of the apparatus that is used.

Best Regard,
Ken


Life is not a journey to the grave with the intention of arriving safely in a pretty, well preserved body, but rather to slide in, broadside, thoroughly used up, worn out and loudly proclaiming,"WOW-WHAT A RIDE"!

73 TR7RV
71 BSA B50 SS
71 BSA A65T
Re: Straightening Amal Concentric (a la John Healy) [Re: Tiger73] #220992
10/28/08 3:10 pm
10/28/08 3:10 pm
Joined: Dec 2006
Posts: 4,037
Massachusetts, U.S.A.
B
btour Offline
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btour  Offline
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B

Joined: Dec 2006
Posts: 4,037
Massachusetts, U.S.A.
There is really not much more to see than what he showed you. You only need imagine the turned piece that you can not see which is in the carb body. I had one made by a machinist friend. Way cool. A carb body with a stuck slide was straightened and when it was speced out, it was one tenth of a thou still out of round was all.

Shhh! don't tell anybody else about this though. wink It is only for the good. Some bike mechanics will get very very mad, if you tell them there is another way than sanding.

John, I would be interested in hearing more about the development of this jig. When was it thought up, and first used etc.

Last edited by btour; 10/28/08 3:19 pm. Reason: add winky

Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.

Moderated by  John Healy 


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