NOTE: MIKUNI NOW ONLY MAKES A UNIVERSAL STYLE FLOAT CHAMBER GASKET THAT FITS BOTH THE TYPE S4 AND TYPE S5 CARB. The S5 also has the external float adjuster around the fuel inlet pipe and uses a 10mm hex needle/seat. Note that the kits will be the same for both 40 and 44mm carb. Looking at the back of the butterfly will confirm size, 165 is a 40mm carb, 175 is a 44mm carb. This is also referred to as the 5 bolt top cover style of carb. Now, once again, these came in both 40mm and 44mm versions but are best known in North America as the 44mm carb. This is the more well known Type S5 carb. This style carb does NOT have external float adjustment and uses a 14mm hex needle/seat. Both 40 and 44's were made in this style. This is the Type S4 version of the 40mm and 44mm carbs, also called the 4 bolt top cover. Throttle Butterfly will have 165 stamped on the back of it. It just looks funky because the Float Chamber Cover is so different. The Type T jet cover gasket and float adjuster gasket are NLA however. Uses standard 40mm Type R kits and parts believe it or not. This unit was OEM for Toyota, hence - Type T, and came on several models that used the 18RG and 2TC/3TC motors. This is the second style of 40PHH, Type T. This unit has the external float adjuster & 10mm hex body needle/seat. Throttle Butterfly will have 165 stamped on the throttle plates. This is the standard 40mm PHH most common to North America.
If the carb says only SOLEX, has a 3 bolt jet cover and says it is made in Italy or Germany or anywhere else in Europe, this is a pure European Solex and has NO interchangeable parts with Mikuni's except a fuel jet.
PLEASE NOTE THAT MIKUNI WILL BE PRINTED SOMEWHERE ON THE CARB, IN SMALL OR LARGE LETTERS, EVEN THOUGH IT MAY OR MAY NOT SAY SOLEX. This page is intended to help identify the type of Mikuni carb by either the top view of the Float Chamber Cover, the Float Chamber cover gasket and/or the Jet Chamber Cover gasket. Mikuni Carburetor Identification for Sizing PLEASE UNDERSTAND WE DO ONLY MIKUNI AUTOMOTIVE SIDEDRAFT CARBS NO BIKES, PWC, SLEDS OR UTILITY/GARDEN EQUIPMENT