fbekholden.com

Ladies and Gents,

I am looking to get my hands on three Amal Monobloc carburettors. My aim is to get them up and running on a Holden grey motor, and learn a little along the way. A grey motor manifold to suit would be nice, but happy to make my own.

Amal made a few different types of carb, but the two most common are the Monobloc (which has an integral float chamber off to one side) and the Concentric (where the float chamber is under the carb). The Monobloc was available from 1955, and hence was around for the grey motor’s hey-day. The Concentric didn’t appear until 1967. I’ve seen a few Concentrics on grey motors, but realistically by the late 60’s/early 70’s the grey had been ousted by the red. Using a Monobloc will be a bit harder on the grey, as they are wider than the Concentric. I will have to use longer runners to clear the exhaust. The Monobloc feels more period correct though.

Monoblocks came in four series: 363, 375, 376 and 389 series. They are described by the series number followed by a size designation e.g. 376 1516 for 15/16" bore diameter. A 'Short' float bowl versions ('S' designation) would be nice, but not a must-have.
As long as the three carbs are the same designation, I am not overly fussed by what shape they are in. Parts are still readily available for them (you can still buy new Concentrics, but not Monoblocs). Something old and covered in crap from lying under someone’s bench would be ideal. Not too interested in $2000 worth of chromed show-carbs.

Cheers,
Harv

Quick look on amalcarb has monoblocs harv - reintroduced in 2014 apparently - not what your after?


You’ll find me lost somewhere!

You’ll find me lost somewhere!

Interesting. Some parts of the Amal website indicate that only parts are available, but clearly they are available as a full carb too. I should have read the website more.

I guess what I'm after are old Amals. Looking forward to the clean-up, parts checking and understanding how they work. The price of new ones is a bit offputting too (about twice the mental picture of what I am thinking of spending).

Cheers,
Harv

no worries - have thrown a couple enquiries to a few Squirrels who are having a clean out

Hi Harv, What Monoblocs do you need (numbers ) ?

I'm open to suggestion on the part numbers. I figure it will be hard enough finding three, so am flexible.

Some (rough) thoughts:
a) The standard Strommie has a venturi diameter of 1 1/32", and runs fine.
b) Twin Strommies (2 x 1 1/32") can be a little boggy, whilst tripple Strommies (3 x 1 1/32") are very boggy.
c) A set of venturi sleeves brings a set of twins down to 2 x 31/32", and crispens them back up (similar on triples).
d) Assume whatever I put these on will be relatively angry, and can handle a bit more carb than a standard grey.
e) Amals are a little more forgiving on bore size (like SUs), as they are a slide carb (not like SUs, which are constant depression). So something like triple 1" carbs should be fine.

The 389 series carbs were available in 1 1/8", 1 5/32" and 1 3/16" (part numbers 389/3632, 389/3732 and 389/3832 respectively). At a pinch, one of these would do but perhaps a little large.

The 376 series carbs were smaller, and were available in 15/16", 1" and 1 1/16" (part numbers 376/1516, 376/1616 and 376/1716 respectively). It's probably three of these that I am after.

The 375 series carbs were smaller again, and were available in 25/32", 13/16" and 7/8" (part numbers 375/2532, 375/2632 and 375/2832 respectively). Perhaps a little on the small side for what I am trying to do.

I can't find a listing for the 363 series carbs by part number, but do have some of them by specification number (the number that was used to assign the carb to a model of motorcycle). I can see 0.475" (363/1 and 363/7), 5/8" (363/4 and 363/5), 11/16" (363/3), 25/32" (363/2 and 363/8), 13/16" (363/9 and 363/11). A little bit of overlap, but again slightly smaller than the 375 series. Too small for what I am trying to do.

Cheers,
Harv

Hi Harv, I had a dig around my boxes of carbies and found a few 376's. The numbers are - 376/303 of which I have two. A 376/5 ,a 376/6, a 376/7, a 376/3, a 376/1, a 376/202 and one labelled 376/i1. I have 12 old Ariels that use the old remote bowl concentric carbs and a 650cc twin which uses the 376 monoblocs,so the above carbs are surplus to me. One of the 303's look to be fairly complete and the others are about 60 - 70%. sing out if your interested. Regards Daz

EK DAZ wrote: Sun May 10, 2020 4:08 pm Hi Harv, I had a dig around my boxes of carbies and found a few 376's. The numbers are - 376/303 of which I have two. A 376/5 ,a 376/6, a 376/7, a 376/3, a 376/1, a 376/202 and one labelled 376/i1. I have 12 old Ariels that use the old remote bowl concentric carbs and a 650cc twin which uses the 376 monoblocs,so the above carbs are surplus to me. One of the 303's look to be fairly complete and the others are about 60 - 70%. sing out if your interested. Regards Daz

Bingo!

The 376/202 carb is a bit of a weird one. I can't find a listing for it - could be either Amal's listings are incomplete, or it has been miss-stamped. 376/200, 376/208 and 376/209 are all 1" carbs, whilst 376/206 and 376/207 are both 1 1/16".

376/i1 is a weird one too. Could be 376/1 or 376/11, but in either case both are 1 1/16" carbs.

Looks like you have two carb sizes. Some are 1":
... and some are 1 1/16":
If it's OK, can I please have either three 1" carbs, or three 1 1/16" carbs. Choose whichever batch seems to be most complete. I'd lean towards three 1 1/16" carbs (the two 376/303's and the 376/1) if possible. Let me know what I owe you.

I promised myself I wouldn't play with bikes again... damn things are more addictive than old Holdens

Cheers,
Harv

I managed to find three Monobloc Amals, with thanks to Darryl. I'll start a thread over here as I learn more about fitting them to a grey:

http://www.fbekholden.com/forum/viewtop ... 25&t=23621

Cheers,
Harv