BSA B33 Inlet Valve Guide- National Scarcity?

[V500]

Mirror polishing is mostly last century thinking anyway. A slightly rougher finish promotes a bit of turbulence which helps with a more consistent fuel/air mix.

[Steve.S]

I imagine Cardiboy just wants to get his bike back on he road. But if you want turbulence, you'd be better off with a squish band.

[Cardiboy1]

Thanks for all your contributions! The story has moved on... and I did find an inlet valve guide, not far from the Crown Jewels in London. See my latest update and call for help!

[scifi]

It is quite easy to turn up some new valve guides, as long as you have the rough dimensions, or modified dimensions, if you wish to gas flow the inlet port.   
There used to be a tuning mod to make the exhaust guide slacker at the port end, to act as a shroud for the hot gasses.   Whether this was useful, it was hard to tell.
To find a supply of Phosphour Bronze, you could look for Car valve guides, such as used by Citroen.   However, check if you need a Cast Iron Exhaust Guide.