6x1.5 6*1.5 6.5x1.5 6.5*1.5 7x1.5 7*1.5 MM (OD*Thickness) Brown FKM FKM Rubber O Ring Washer O-Ring Oil Seal Gasket - buy at the price of $0.80 in aliexpress.com | imall.com
NOS Honda TRX650 680 CBR600 Front Crankcase Cover O-Ring 6X1.5 # 91315-PC9-004 | eBay
O-Ring - Carburetor - 6.6mm x 1.5mm - Mikuni | Vintage DIY Motorcycle Parts | Dime City Cycles