Road Rocket or not a Road Rocket ?

[wood_dene]

Hi from a newbie in Eastbourne, UK

I have recently acquired a 1956 BSA A10 Road Rocket, well, that was how it was advertised and it has Road Rocket on the log book.  Now, being a Velo Fellow, I am not so conversant with BSA's but I am learning.

The frame No. is EA 76965 which seems correct for 1956 but the Engine No. is DA10R 3180 (HC) which appears to be a 1961 Super Rocket. The cylinder flange is the thick type i.e. 1/2"

But the mystery deepens. As it was running rich, I took of the Amal Monobloc and measured its size as 1 1/8" but the inlet manifold is 1 3/16"

Now the only reference I can find for 1 3/16" is for a 1962 A10RGS . Also, there is a stamping on the head which looks like 51B24AO

Just to make things more interesting, the magneto is a Lucas Competition Model and the wheel rims are aluminium !

You can see a picture of the bike at http://www.twala.co.uk/p881393973/h5a9cf6c4#h5a9cf6c4

So, all of you BSA people - just what have I got ?

[muskrat]

G'day wood_dene, welcome to the forum.
Really nice looking bike mate. She's got the right hubs for '56-7 and the tacho drive of the mag is pre '58.
Bikes of this age have more than likely been played with. Find a 1 3/16" carb and have fun.
Cheers

[bsa-bill]

Hi wood_dene

As muskrat says, fine tidy looking bike.
Quite possible the engine's been replaced at some point. lots can happen over a fifty odd year time span, I wouldn't worry about it

[KiwiGF]

and it's also possible the head has been "gas flowed" - my iron cyl head has a a inlet of 1.25" - should be 1 1/16" - it seems to still run Ok with a 389 (1 1/8") on it.

Back in the seventies if I blew an engine on my 59 Super Rocket I'd nip down to the local brit bike breaker in ladbroke grove - north london - and pick up a "short engine" (just cases and crank etc, no barrel) for a tenner or so, we did not care about keeping the numbers original back then!

[chaterlea25]

Hi and Welcome,
Nice looking bike
The number to look for on the cylinder head is on the underneath of the inlet manifold in raised numbers
it will end in one of these 1126, 1549 or 1571 where the 49 has been ground off and 71 overstamped
Dont get worried about the number too much as the heads are outwardly identical
"normally" the 1 3/16 in inlet is the 1571 head, BUT I have had a 1 1/8in. (or maybe 1 5/32??) one, and conversly a 1 3/16in. 1549
All looked as if they had not been got at

Cheers
John

[a10 gf]

Hello & welcome to the forum, am hoping you will find the membership useful. & bike looks great!

[trevinoz]

Looks nice.
Tank is 1958/9.

Trev.

[A10 JWO]

Real nice bike, don't worry about the critics that hang about in groups at jumbles, just enjoy.

Welcome to the group.

Colin

[wood_dene]

Mystery solved.

Well my 1956 Road Rocket is indeed registered at the DVLA as a genuine Road Rocket but I have now learned that it has been imported from the USA.

This may explain why it has a Road Rocket frame, the bottom end from a Super Rocket and a cylinder head from a Rocket Gold Star.

I have fitted a new Amal Carburettor which now matches the 1 3/16" port having found that the original carburettor was for a Matchless !

Now I have to sort out the dragging clutch ;-)

Steve

[A10Boy]

That will probably be a doddle after a Velo 

[JulianM]

Really nice looking bike!

Julian