¹ I assembled this table using official Honda specifications booklets when I first built this website way back in the 1990s. I was honest and sincere and worked hard in my transcription. Unfortunately, in the face of my own subsequent experience as well as the many helpful suggestions of others (thank you Stu and Larry!), I have found that Honda was not so forthright. There are a number of errors. I am correcting them as I learn of them, and welcome suggestions. Oh, and any replication of this table found elsewhere has been copied from my original.

² Carburetor throat size (the engine entry diameter) and venturi size (the narrowest part of the carburetor bore) are commonly quite different on production, non-racing carburetors. Thus a carburetor's true, effective (limiting) size is the size of its venturi. This is why for example the Honda CBX is said to be 28mm, though it measures XXmm at its entry point. Many carb designs add to this apparent confusion in that many of the various mdoels of one casting style or family are all the same venturi diameter, varying only by throat diameter. All the GL1000s, for example, are the same venturi size, but have two different throat sizes. Even more variations are found within the vast Keihin VB series fitted to nearly every road bike Honda made during the late 1970s, all of which use the same size slide, despite having many different throat sizes. While carburetor throat sizes are easy to determine, venturi sizes are less so, because for one thing they are typically oval in proudction carbs. For these reasons I have in this table used the non-standard convention of listing throat size in the place of venturi size. While not correct practice in measuring carbs, it is what most people do.

³ Pressed-in, conventionally non-removable idle jet.

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