I was thinking of chain gaiters in my earlier reply. I think the BSA type fork gaiters are part no 42-5320 and they are 190mm long and readily available. The ones on my bike were 220mm with the same end diameters as the BSA gaiter. I used Hi Level Part Number 263721 as replacements which are 220mm. I got them on Ebay but can't find them any more though they are still available from Hi Level. The following is similar only 200mm long:
http://www.ebay.co.uk/itm/321069729897?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITThe sides of the gaiters had to be ground off to fit between the mudguard and fork leg.
Hope this helps.