You can find all the part numbers using the Yamaha online parts catalogue:

http://www.yamaha-motor.eu/uk/services/online-parts-catalogue/index.aspx

FYI The grey plastic tank protector part numbers (known as air scoops!) are:

LHS: 11D-F137W-00
RHS: 11D-F137X-00

As for the tyres... Well there are loads that would suit! Everyone has a different opinion, but from what you describe I'd suggest looking at Continental TKC70?

http://www.xt660.com/showthread.php?t=23588

https://www.conti-online.com/www/motorcycle_de_en/themes/motorcycletires/enduro/tkc_70_en.html

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