Author Topic: 49' A7 twin carb help.  (Read 1975 times)

Offline GuyboA10

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49' A7 twin carb help.
« on: 01.01. 2009 07:58 »
Gday guys, i'm just asking this for a friend. He has a 49' A7 with single 626 carb and is interested in going down the twin carb road. Any thoughts? Does this improve the top end? any other increase in performance ? Is is worth doing or does it just add extra troubles having 2 carbs? being that ive got an A10, he wants to get as much out of his engine.lol Where can u get the manifolds? cheers , Guybo.
ps here is a photo...

Offline LJ.

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Re: 49' A7 twin carb help.
« Reply #1 on: 01.01. 2009 11:04 »
Other Star Twin Laddies will chip in soon with their opinions. From what I have gathered a single carb is good enough without all the fiddling about in setting up two, there isn't much improvement BUT there is that 'look good' factor of having twin carbs and would likely be a great talking point at shows or various classic bike gatherings.

I am just waiting to find a carb as near to the one that I already have. I currently have a 276 DP/1A amal with a 15/16th carb bore, luckily I have the left hand one which is supposed to be the harder to find one.
Main jet 140. Needle jet 0.107. Also reccomended is a 276 EC/1B.

If your mate can get the parts then give it a go. That is one superb looking bike there and should keep up easily with an A10, I'm loving mine to bits its sooo smooth, just got to finish running it in as the previous owner had done various engine work on her, I'm also still in the 'getting-to-know-how-she-likes-starting' mode. So by Spring I should be ready to go twin. Wish him luck from us and do keep us updated of his progress. Is he able to get online and join us?
Cheers
LJ.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline A10Boy

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Re: 49' A7 twin carb help.
« Reply #2 on: 01.01. 2009 18:39 »
That is a lovely old A7, and I cant help feeling that trying to get more speed out of it is slightly missing the point.

Also, sticking twin carbs on it without the other "breathing" areas like gas flowing and camshafts being addressed is probably a waste of time and money. If your friend wants more speed, why not just go and buy a Bonneville ?
Regards

Andy

1958 Super Rocket
Plus
Harley Super Glide Custom
Yam XJR 1300

Offline GuyboA10

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Re: 49' A7 twin carb help.
« Reply #3 on: 03.01. 2009 05:23 »
Hey, yep it is a great bike. Thanks LJ for the feedback, goodluck with the 276's. That'll look cool, i hope it goes well. Yes, the owner ,Phil, has just joined up! he should be here asap. As far 'as missing the point' , i never mentioned anything about 'speed',  i did however mention performance which was the point of the enquiry. Anyway, Phil ( owner of the a7) has now joined up. Cheers, Guybo.

Pixies

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Re: 49' A7 twin carb help.
« Reply #4 on: 03.01. 2009 06:17 »


Ok...been hearing lots about this site from Buddy Guybo....

Bonneville??? Why would anyone do somehing like that?    Performance, and original cool, BSA has the goods....

Im always into peak performance, not refering to speed...
What I am interested in is getting the best sound, and chunked up tone. To use Alt pipes or not this is my concern & whether twin Carb or not will compliment this.

The pic that Guybo posted is and old picture, I have added an update...

Thanks for the compliments ...she is a cool girl

 

Offline LJ.

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Re: 49' A7 twin carb help.
« Reply #5 on: 03.01. 2009 10:58 »
Hi Phil... Great of you to join us! There are a few of us Star Twin owners here now and a good splattering of Star Twin posts in the forum archives too. I think you've just gotta try out the twin carb conversion or you'll always be wondering whilst you have the bike. The main problem might be in getting that twin carb manifold, I've been lucky to get one recently, however I think if you shout about for long enough one will turn your way. Interesting point you make about a different sound from fitting twin carbs, that's another point for me to compare with when I get mine done. My silencers are the Campbell types similar to Burgess silencers, I dont know if you get them down your way (presumeably your in Oz?) They are straight through silencers probably made in a similar way to Gold Star silencers but with the original BSA shape like you have fitted now.

Look forward to your news and progress, Keep us updated wont you.

Cheers
LJ.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline A10Boy

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Re: 49' A7 twin carb help.
« Reply #6 on: 03.01. 2009 19:16 »
Er sorry, I obviously wrongly thought the original question "Does this improve the top end? " referred to more speed... My mistake...
 *conf*

Anyway, welcome to our happy forum.
Regards

Andy

1958 Super Rocket
Plus
Harley Super Glide Custom
Yam XJR 1300

Pixies

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Re: 49' A7 twin carb help.
« Reply #7 on: 03.01. 2009 22:28 »


No worries mate...Emails always never get the full intent of a conversation....

And my idea of performance would be compleatly fiff to anothers. What im interested in..is like i said tone and efficiancy.

Actualy...the louder the better, 'without' drillin holes in my mufflers...

Any thoughts..?

Phil