Got mine from here http://www.ebay.co.uk/itm/vw-camper-beetle-solex-31-34pict-3-carb-repair-bushes-AIR-COOLED-/271117778963?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f1fe10013 If that's what your looking for ive not used mine so I can't say if there any good though
I did mine not long ago, the only thing I found was that they were a little bit loose; all I did was bond them in with epoxy. All working fine now
I think I got mine from here http://www.onlinebearings.co.uk/plain-metric-bush-5-20-mm-inside-diameter-c-67-p-1-pr-16426.html The size is something like 8mm internal x 10mm external. Cheaper than the eBay guy!