>Just a hypothetical question...
>
>What would be the effect on performance if the regular air filter in a 73
>Westy was supplemented by an additional  "medium sized bird nest including
>a few baked feathers" filter, underneath the pleated paper filter.
>
>Was this a factory option, or was it more likely to have been installed by
>the dealer?   Can I still get parts (twigs, wool) or will I have to replace
>the entire "bird nest" as an assembly?

You're lucky this is a'73. On later models these were replaced with a 
computerised tangle of wires and diodes. It doesn't do a significantly 
better job of bunging up the filter, but it is a sealed-for-life unit, costs 
a king's ransom (only available from authorised dealers), has umpteen 
mystifying connectors and is guaranteed to fail with annoying regularity. 

Andy E.

A.C.Erskine@lut.ac.uk