Yamaha Parts:
$5 - OEM YPVS Oil Seal part# 93108-23010-00 - Fits RZ350 DT125 DT200 WR200 TDR250 TZR125 TZR250
https://www.bikebandit.com/oem-parts/detail/yamaha/93108-23010-00/b1277467
https://www.bike-parts-yam.com/yamaha-motorcycle/assignment_spare_parts/93108-23010-00
$5 - OEM Oil Seal part# 93102-25061-00 - 25mm x 40mm x 8mm - Crank Shaft or Rear Wheel Oil seal fits many 70s thru early 90s models - YZ250 YZ465 SR500 TT500 XT500 IT250 IT400 MX175 MX250 etc.
https://www.partzilla.com/product/yamaha/93102-25061-00
https://www.bike-parts-yam.com/yamaha-motorcycle/assignment_spare_parts/93102-25061-00
$5 - Oil Filter - Vesrah SF-2003 - fits XV250 SR250 BW350 TDM850 RIVA XC200 TT250 TT500 TT600 XT250 XT500 XT600 YFM600 Grizzly YFM700 Raptor Vision XZ550 Virago XV250 XV535 XV700 XV750 XV920 XV1000 XV1100 V-Star XVS650 XVS1100
$10 - OEM Crankcase Cover Gasket part# 4DW-15462-00 - Fits TT600 XT550 XT600 SRX600S
https://www.partzilla.com/product/yamaha/4DW-15462-00-00
http://www.2wheelpros.com/oem-parts/yamaha-gasket-crankcase-cover-3-4dw-15462-00-00-part.html