O-Ring - Carburetor - 4.0mm x 1.0mm - Mikuni

Mikuni carb O-ring measures 4mm x 1.0mm. Fits needle jets and other applications.

Equivalent to OEM Yamaha O-Ring 93210-03142-00- Needle Jet - used on multiple bikes including - XS1, XS2, XS650, TX 650's (1970-79) with Stock Mikuni BS38 CV Carbs. If this O-ring is dried out, shrunk or damaged, fuel can pass around the outside of the Needle jet instead of just thru the jets center causing a richer carb fuel mixture. Note: O-Ring appears too small but it is correct, install by carefully stretching with pointy needle nose pliers until it just fits over the jet.