James 1928 V Twin 500cc parts and help needed

[cardan]

I must admit I'd never seen - or perhaps never noticed - a concentric Binks-AMAL until the last week! No idea what they were fitted to, so it could be a lawnmower or similar. The first year for AMAL (Amalgamated from Binks, AMAC and B&B) was 1929, but for a year or two there was some mixed branding, the most common of which was Binks-branded carbies (not the lawnmower type!) mounted on Nortons in 1929, and maybe 1930. Rare these days. The AMAC brand was used on the continent many years after it disappeared in the UK.

I've been amusing myself over the last month or so sorting out the year-by-year features of AMAC and B&B and trying to sort out bits in my carby junk box. Interesting activity once you have some knowledge.

Leon

[cardan]

John we were discussing B&Bs and I mentioned the very nice one you pointed to on ebay was too early for 1928. However there is one for sale on ebay at the moment http://www.ebay.co.uk/itm/252444276646 that would suit a sporting bike from 1924-1928 (although it might be a bit big for the James). The pilot jet arrangement on these B&Bs is quite interesting, and one of the photos on the listing (below) shows it very nicely. There are two adjusters for the pilot jet, one on either side of the mixing chamber. One controls the air, the other controls the fuel. Presumably you could get a very nice idle!

B&B carburettors were very sophisticated - they were the first of the major British makers to use a tapered needle attached to the throttle valve (1913-14), and in 1915 they brought in an adjustable pilot jet for easy starting and reliable low-speed running.

Cheers

Leon

[chaterlea25]

Hi Leon,
Thanks for the link and information,
I do not have any experience of B&B carbs
Most of my limited experience is with AMAC's from 24 to 28

Regards
John

[cardan]

Hi John,
I'm just bubbling over with carby info at the moment, so happy to share it. The AMAC was also a fine carb through the 1920s, and while I suspect they had the edge for outright performance they didn't bring out a carb with a pilot jet until the PJ series in 1926-27. I guess they didn't care too much about idling in those days!
Here's a c1927 AMAC PJY. As the caption says there were three sizes, as well as top and bottom feed variants (PJX and PJY). AMAC were good at stamping identification marks, so if you find an original AMAC the code (eg PJY15) will identify it immediately.
Cheers
Leon

[DavidR]

Many thanks to you all- you are certainly a mine of knowledge- the inlet manifold is 1" so I have plenty of choices
Second question now that I have the carb sorted....
Does anyone know the specifications of the valve springs for the 500 V twin James (1928) I can get them made but need to supply the factory with all the particulars- any ideas ?
Cheers
David

[cardan]

Hi David,

Time to find a fellow 500 James owner I think, or at least the VMCC James Marque Expert. Valve springs are a pain unless you have a sample to go by.

Even though very sporty bikes, like OHV Nortons or 4-valve Rudges, were starting to get very strong valve springs by 1928, I suspect the James s.v. would use soft-ish springs. I reckon that a "two thumb lift" would be about right. Be suspicious if you end up with valves that can't be lifted from their seats with your thumbs - it won't help performance but it will ruin your cams and followers.

Cheers

Leon