I found parts scematics to view for a 1978 Yamaha Chappy here: http://www.cmsnl.com/yamaha-lb50pe-19781979_model8675/partslist/B-01.html
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http://manuals.wotmeworry.org.uk/More%20Manuals/Yamaha/Yamaha_Neo's_50-Service_Manual_(2002).pdf
You can download it here -> http://pdftown.com/PDF-Yamaha-FZR600-Service-Manual.html
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PDF have the software download it from there
If you go to the Yamaha web site and register with the site, you can download a PDF of the original manual free of charge. This applies to many of the makes and models from Yamaha. The manual will detail specifics of the plugs needed as well as details on how to replace.
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