My husband restores old cars/bikes etc and has had good luck with finding what he needs manuals/parts on ebay, good luck.
service manual here http://www.repairmanualclub.com/index.php?dlid=686
Full PDF versions of the Owners Manual, Service Manual, and a supplement manual. Wiring diagram is in the service manual. http://www.mediafire.com/?0mzulnyzogg http://www.mediafire.com/?8zubjzjyioj http://www.mediafire.com/?34muedntyxz
You can download a copy from: http://www.starmotorcycles.com/star/service/viewmanuals
The fuse box diagram is in the service manual. The 1996 Maxima manual is available through most auto parts.
Ebay type site or might be able to get a reprint through a dealer.
Purchase a service repair manual for the vehicle.
You can find a Parts and Service manual CD ( in PDF ) for the XJ6 ( 1995-1997 ) at Coventry West in Lithonia, GA.
http://www.Yamaha-motor.com/outdoor/service/servicehome/home.aspx Register there for more info I have scanned an entire service manual ( not just the owners manual) This is 72 pages for the Yamaha EF 600 generator. I have it in PDF file. E-mail me for a copy. My E-Mail is ewcrandall@roadrunner.com these sell for $55.00 at the Yamaha web site. I do accept $10.00 dollar donatons.
To find the displacement on a Yamaha Moto4, you can check the owner's manual, which typically lists the engine size or displacement in cubic centimeters (cc). Alternatively, you can look for a stamped number on the engine block itself that indicates the displacement. If these options are not available, you can contact a Yamaha dealer or service center for assistance.
Ebay you can find anything on there.
try googling for "service Manual" plus make and model and year of your vehicle
You can find diagrams for fuel and vacuum lines for a 1983 Yamaha Vargo 500 in the owner's manual or service manual for the specific model. Additionally, online forums dedicated to vintage Yamaha motorcycles, as well as websites like Yamaha's official site or parts suppliers, may provide downloadable diagrams or detailed guides. Websites like Motorcycle Manuals or specific enthusiast groups on social media can also be valuable resources.