This is a double-edged sword, I reckon. Part of the appeal of restoring a British bike, or at least keeping one on the road, is the wide availability of spares for them. You can build an entire Vincent twin or Commando from spares these days and probably a Bonneville too. This has led to inflated bike prices, even for projects, as novice restorers look on them as easy projects. It also means there's a huge demand for pattern spares, usually made cheaply in the far East or India. These pattern parts are copies of old, worn out bits, or even copies of copies, no wonder they don't fit. I've been offered countless new restos that have dodgy fitting exhausts, lights that don't etc, all lovingly restored using pattern parts and ending up with a tragic motorcycle. I recently saw a Indian made BSA tank, supplied fully painted for £450 ( including chrome). It fitted where it touched and had THREE pairs of different-sized tap holes in the base to cater for all tastes! Inside, you could clearly see that it had been fabricated from some sort of metal road sign. But to have that hand made in Britain, then chromed and painted, would cost at least a grand. For a market of what? twenty a year?
If you restore an old Italian or Japanese machine, the pattern spares supply is almost non-existent, excepting the obvious Z1/CBX etc. The restorer has no choice other than to try and find original parts, usually at silly money. But they fit! This makes it a long and expensive job, to be sure, but the end results can be brilliant.
I've seen a massive surge in people buying scruffy, broken and damaged original British parts, seemingly for stupid money, but at least you know they are likely to work.
Cheers
ATG
Paul