Yamaha TT-R90S Manuel D'atelier Du Proprietaire page 198

CARBURETOR
1. Measure:
Fuel level a
G
Use a fuel level gauge 1.
Out of specification → Adjust.
Fuel level gauge:
YM-1312-A/90890-01312
Fuel level:
2 ~ 3 mm (0.08 ~ 0.12 in) below
the float chamber line
4 - 7
ENG