looking at david silver spares facebook page and he has a lot of new 400f parts coming on line soon.
these include headlight with h4 fitting,new type of cam adjuster,new chain guard.
also on his webpage,there are a lot of new 400f articles.just click on d.s. stories.sorry about not adding links but i am computer illiterate. ray. also a mention that the 400f2 model was fitted with longer head bolts which cured oil leakswhich occured on earlier models