Author Topic: Looking for some carb advice please.  (Read 755 times)

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Offline grsymes

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Looking for some carb advice please.
« on: January 08, 2019, 10:03:02 pm »
I need to start looking for a carb for my 49 C11 but I know nothing about them.
I've being given names of a few people to contact about them but I want to be sure I'm asking for the right item.
What make/model/specs should I be looking for?

Thanks
1949 Rigid Frame ZC10 5687
1950 Engine ZC11 11149
Slowly coming together

Offline Owen

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Re: Looking for some carb advice please.
« Reply #1 on: January 08, 2019, 10:05:15 pm »
For 1949 the model was 274au/1da. You will find the data here for the correct carburettor.  https://bsac10c11c12.co.uk/smf/carburettor/carburetor-data/
 Do you have a problem with you existing carburettor or need the whole thing?
« Last Edit: January 09, 2019, 06:45:44 am by Owen »
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc

Offline grsymes

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Re: Looking for some carb advice please.
« Reply #2 on: January 08, 2019, 10:19:28 pm »
So it's a 274au/1da I'm after.
Thanks
1949 Rigid Frame ZC10 5687
1950 Engine ZC11 11149
Slowly coming together

Offline Owen

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Re: Looking for some carb advice please.
« Reply #3 on: January 09, 2019, 06:47:35 am »
Doh
I've got C10 fever. Now  corrected.
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc

Offline grsymes

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Re: Looking for some carb advice please.
« Reply #4 on: January 09, 2019, 07:40:32 am »
I need the whole unit.
Is there a modern device that could fit too?
1949 Rigid Frame ZC10 5687
1950 Engine ZC11 11149
Slowly coming together

Online hampshirebiker

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Re: Looking for some carb advice please.
« Reply #5 on: January 09, 2019, 08:14:59 am »
Buy a new Monobloc. Surrey Cycles or Hitchcocks should know the correct size and spec. Don't be tempted by a Concentric.
Postal - Liphook Hants - But just into West Sussex.

Offline timsdad

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Re: Looking for some carb advice please.
« Reply #6 on: January 09, 2019, 08:29:01 am »
Any carburettor of the correct size will do the job, Mr G. BSA just used what was available at the time and the later Cs had Amal Monoblocs and, if they had continued production, would have then been updated with an Amal Concentric.

Concentrics were measured in metric so the nearest equivalent to the old 25/32" size would be the Mk 1 Amal 622, which at 22mm choke size is fractionally bigger than the old Imperial size - near enough, in my opinion.

I'd strip it, clean it, fit new seals and gaskets, a 100 main jet, needle in the middle notch, mixture screw one and a half turns out from lightly screwed fully in and leave everything else as it is. The throttle stop screw needs setting so it's just starting to lift the slide when you're peering in at the back. It doesn't need any of the choke paraphernalia so this can be chucked away and the top screw hole left open - it does no harm.

It will fire up and should run well after a bit of twiddling with the throttle stop and mixture screw. Fine tuning of the main jet, if needed, can be sorted out in due course after any problems of air leaks at the flange, dribbling float needle and blocked galleries are attended to.

If you pay good attention to cleaning and checking, probably refacing of the flange on a bit of wet-and-dry paper, paraffin and an old mirror and cleaning up of slide and body so it slides up and down nicely, then it'll be fine and want little attention.

You can pick these carbs up in decent condition for about a tenner from an autojumble or maybe twenty quid off e-bay. A fiver or so for seals and a jet (if needed) direct from Burlen and you're sorted. Any new Oriental carb of the correct size will also do the job but an Amal will look better. It was Stage 1 tuning for us young lads in the '60s!


Added after I saw hb's posting - I really don't know why these old Amals get slagged off so I have to disagree. I've overhauled many of them over the years, after neglect and abuse, and I find them very forgiving. They always start and run well however they're abused and genuine spares have always been available.


Ray
« Last Edit: January 09, 2019, 08:35:20 am by timsdad »
Just a motorcyclist.

Online Tman

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Re: Looking for some carb advice please.
« Reply #7 on: January 09, 2019, 09:35:23 am »
Yes, I see no problem with Amals, in general. I did buy a new pair of Concs some years back and the buggers were still full of swarf from the machining processes, but the Amal Premier I bought back in the Autumn for the A7 means it now ticks over like the proverbial Swiss watch. Very impressed.
When I've bought used Amals (like 276s) in the past I've only worried about the model and choke size, and disregarded the suffixes as there's a possibility that the jets etc will need playing around with anyway.

Offline grsymes

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Re: Looking for some carb advice please.
« Reply #8 on: January 09, 2019, 07:48:52 pm »
Timsdad, thanks for the walkthrough guide.
I'm looking at a few sites selling Amal carb and its all beyond me. I need to contact the retailers and find a complete running carb that I can just bolt on then tune as needed. The idea of buying one that needs work is daunting to me I wouldn't have a clue.
1949 Rigid Frame ZC10 5687
1950 Engine ZC11 11149
Slowly coming together

Offline Donald

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Re: Looking for some carb advice please.
« Reply #9 on: January 09, 2019, 08:55:43 pm »
Hi all
Grsymes, any amal monoblock or concentic carb are so simple to strip it is difficult to mess it up ,just take a few photos as you dismantle it , and don't over tighten the screws and nuts when reassembling

Online hampshirebiker

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Re: Looking for some carb advice please.
« Reply #10 on: January 09, 2019, 09:30:23 pm »
IMO a Monobloc every time. They were standard fitment on later Cs and are available new. If that doesn't fit grsymes' requirements perfectly, I don't know what does.
Postal - Liphook Hants - But just into West Sussex.

Offline Owen

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Re: Looking for some carb advice please.
« Reply #11 on: January 09, 2019, 09:33:26 pm »
There are usually plenty of the correct carbs coming up on eBay that just need a good clean.
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc

Online hampshirebiker

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Re: Looking for some carb advice please.
« Reply #12 on: January 09, 2019, 09:40:12 pm »
So you're saying that the Ebay carbs will just bolt on and work properly. You'd be very lucky with a 60 year old carb.
Postal - Liphook Hants - But just into West Sussex.

Offline Owen

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Re: Looking for some carb advice please.
« Reply #13 on: January 09, 2019, 09:48:05 pm »
RWWS
1940 C12 (350cc)
1945 C10 & C11
1953 C10 & C11
Anyone want a B20 in need of a lot of tlc

Online hampshirebiker

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Re: Looking for some carb advice please.
« Reply #14 on: January 09, 2019, 09:58:53 pm »
What does that mean Owen?
Postal - Liphook Hants - But just into West Sussex.