The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Amal, Carburation, Fuel => Topic started by: AZScott on 23.12. 2014 22:56
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Hello, I am restoring a 1957 BSA A10 Super Rocket, ( Yes a well documented 1957 ) The carb on it was a Monoblock 389/004, with a #400 main jet.
The references I have seen do not show an application for a 389/004. My friend has a 1958 Super Rocket with a 389/031.
Does anyone know what the proper Amal number for the 1957 A10 Super Rocket should be ?
Appreciate any help.
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The amal website has a search function for that purpose;
http://amalcarb.co.uk/?SID=aked5m6ftq00d6ge9t551rqc64&___store=amal
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G'day AZScott, *welcome*
Here's a scan of my reference books. First one is BSA Twin Restoration, the second is BSA Twins and Triples, both by the same author. Looks like a bit of a mine field around then, especially if yours is a USA export model. The /004 would have been a base model and jetted by the user. 1 5/32" with a 400 main is close to the 389/46. My ? is what size is the manifold/port size? The carb and the manifold size should be made the same.
Cheers
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Muskrat, thanks, Appreciate your response.
I know documentation is not clear, and most show the first year of the Super Rockets as 1958.
Manifold port measures 1 1/8" and the 389/004 carb is a 1 3/16". So there is a problem there.
On early Super Rockets I have seen documents that say they had a TT Racing Carb.
I am not sure if this referrers to an Amal number 389/XXX, or if Amal stamped them as TT.
In your documents I see a TT9, never seen one, Is this a different casting from a 276 or 389 ?
My Triumph Trophy C model used a 389/239 with a #330 Jet, and the Amal reference is not clear on this one either.
Again thanks
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G'day mate.
TT carbs are different, one on ebay now. They fetch a pretty price.
http://www.ebay.co.uk/itm/AMAL-1-3-16-10TT9-WITH-REMOTE-FLOAT-/281534236137?pt=UK_Motorcycle_Parts_13&hash=item418cbf85e9
It wouldn't be hard to open up the port to match the carb. For daily road use I'd stick with the mono.
The 389/31 is a RR carb, your mates SR should have 389/36. The numbers only matter if your going for concourse trophy's. The /31 and the /36 are the same.
Stick with your /004 and open the port to suit, jetting should be close to 389/46.
Cheers
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Thanks again Muskrat !!
Great information. I think I will take your advise and stay with the 004 and make it work.
AZScott
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Just also keep in mind with dating that August to December 1957 were considered 1958 season bikes.
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According to a book that I have just picked up at a local autojumble it is an AMAL reference catalogue it lists the 389/31 as a carb for the A10 Road Rocket Twin (export) 1959-60. The 389/36 1959-60 is listed for the home market and all internals jets etc. are the same as the 389/31 only difference being the home market carb was fitted with an air filter. There is also a 389/37 1959-60 listed for the home market without the air filter and the only difference is it has a 400 main jet whereas the air filter carb has a 290 main jet. Strange though that the export carb 389/31 without the air filter is listed as having a290 main jet. The T10TT9 carb was fitted to the A7 Star Twin 1952-54. A10 Super Flash1954. A10 Road Rocket (home &export) 1955-57. A10 Super Rocket (home) 1960-61 and the A10 Super Rocket and Spitfire (export) 1960-61