I've been doing some research, and it seems that although the 'general maintenance' bike manuals for 400's of all years are available in English, only the VV ('95 onwards) variable valve engine manuals are available in English.
The 400VP (or VC) engine manuals - '92, '93, '94 - are only available in Japanese.
Has anyone got a VP engine manual in English?
Does anyone know the difference between the two variable valve motors - the VP and the VV?