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Author Topic: Twin Carb envy!  (Read 542 times)
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alanp
Plymouth, Devon
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« on: 17.03. 2011 16:26 »

I parked my RGS rep A10 next to a Gold Star and a twin carb '59 Bonneville the other day and have to admit that the other engines looked much better with the carbs in clear sight than mine. I know twin carbs can be a nightmare to set and keep set but....if only mine had twin carbs.
I know that occasionally you see twin carb A10 heads on sale but very very rarely and big money is involved.
Has anyone any knowledge of the possibility of converting the A10 head to twin carbs?
Thanks
Alan
PS I know there is another topic on twin carb heads going but I'm interested in modifying a standard head.
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bsa- bill
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« Reply #1 on: 17.03. 2011 19:33 »

Can't give names (don't know them) but there are guys who convert heads to twin carb, maybe some one else has more info
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All the best - Bill
Goldy
Warwickshire, England
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« Reply #2 on: 17.03. 2011 21:15 »

I cannot see the point in doing that other than giving the ethanol two carbs to attack instead of one.
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56 A10 Golden Flash - Restore, ride, relive.                                           
56 C12 BSA project ongoing
bsa- bill
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« Reply #3 on: 17.03. 2011 21:36 »

Quote
I cannot see the point in doing that

10% zing 90% bling

But if blings your thing - way to go
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All the best - Bill
trevinoz
Newcastle, N.S.W. Australia.
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« Reply #4 on: 17.03. 2011 21:38 »

It's a big job, Alan.
                               I have seen a few but it involves cutting off the manifold, fabricating new stubs and having them welded on.        
                         Trev.

I haven't actually seen one mounted on a bike yet so I can't offer any opinion on performance.
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Taffy
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« Reply #5 on: 18.03. 2011 09:00 »

eBay 200587583731 about as good as they go.Most if these are stateside.I've seen them on A10s but they are for looks more than anything.Yes extreme track use with tt gp carb may be usefull!!
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A10Boy
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Solihull, Near Birmingham England.


« Reply #6 on: 18.03. 2011 10:05 »

I remember reading somewhere that when Triumph converted the T110 to twin carbs to make the Bonny, BSA tested twin carbs on the A10 and found that it made no detectable difference upto about 99% of full speed and added only a few MPH at the top. My view is that when twin carbs were fitted to the A65's it was more of a fashion thing to sell higher numbers in America. Most of the power gained on the hotter models was from better breathing, higher compression and more sporty camshafts.

Call me old fashioned, but I think a well set up single carb is better than twin carbs unless you are going racing.
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Andy

1960 A10 - Black Golden Flash
1973 Z1a - Fast
1960 AJS Model 31 CSR - Beauty
Jim
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« Reply #7 on: 21.03. 2011 18:52 »

I've got an early dual port alloy A7 head which has a detachable manifold, if you remove the manifold you can convert the head to dual carb and it should fit on an A10. This is what I hope to do at some stage, putting 30mm MkII concentics on it. There would appear to be a fair amount of work needed in porting the head. I have few illusions about any performance gain but I agree with alanp about the aesthetics.

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Wimbledon, England.
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Jim
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« Reply #8 on: 21.03. 2011 19:15 »

Just found a rather poor photo of the head with a 30mm manifold attached to show how much metal needs removing. Hopefully it has uploaded.


* A7 head.jpg (149.96 KB, 800x436 - viewed 46 times.)
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Wimbledon, England.
BSA A10
BSA B44
BSA B40
Moto Guzzi Le Mans
Buell XB12R
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