Different Cast Iron Valve Guides - Super Flash

[MikPowl]

The head on my SF is cast iron but the part no's for the valves and valve guides are different from the normal cast iron A10. New valves aren't a problem as they're the same part as fitted to the later Road Rocket.  But the part nos for the SF valve guides are unique to that bike, it seems. The usual A10 guide is 67-31 for In and Ex, but the SF is 67-931 and 67-932 for In & Ex respectively. Googling these numbers goes nowhere!!  The RR part no is different again - 67-1140 - but they are for an alloy head and I guess they are bronze.  Does anyone know what is the difference between a 67-31 and a 67 -931 guide? 

[bikerjohndavies]

Hi,
Sorry, can't help with the valve guide question as I left mine alone as they looked fine when restoring the head. I was wondering if you have an original Super Flash head on your bike or a standard iron one? They both have a casting number on the underside of the inlet manifold, 67-251, but the Super Flash ones had a stamping of 966 somewhere next to it to show it had been modified as in the attached picture. I'll send you a PM with my phone number if you want to talk more.
Cheers, John

[sean]

possibly SRM has the info I bought collisbro guides .020 oversize and turned the od to fit the id of each guide hole cant remember the interference  fit but SRM will tell you .
good luck

[MikPowl]

Thanks for your help. That's very interesting that there should be a special stamping on the head - I'll have  good look when i get home next week. I'm pretty sure it's the original head as it has the R/R valves, tho the ones now fitted are marked with the V-number equivalent (Alpha?) The bore is out to +60 and the crank has definitely been worked on - it's being checked at the moment to see if it's an easy repair or if more drastic attention is needed. I found the bike in HKG. If the head had been changed no way would they have bothered to fit valves and guides from an SF- they'd have gone with whatever came on the head they had to hand, but the guys working on bikes there were consummate bodgers. They had to be - getting spares out there was a big deal.  My bike is one of the very last batch sold and has the '54 'upgrades', notably the large finned head and barrel. The BSA Owners Club confirmed the frame/engine numbers but my engine is missing the 'S' stamp.  I think by this time BSA had the s/a frame out and just wanted to get rid of the old stock to whoever. John, if you could send me your phone I'd very much like to give you a call as you've obviously been down the path I'm now treading!  I'll also take the advice to contact SRM - they've rebuilt a few SF's, I think.

[bikerjohndavies]

Hi, I sent you my phone number via PM (Private Message). Give me a call when convenient. Cheers, John