Carb question

[mxgrant185]

I have a 96 m900, how do you tell what the size of the carbs are? I know they are either 38mm or 40mm. From what I've read. But how do u tell.

[koko64]

38 mm for oem.

[mxgrant185]

I read online they could be bigger though, or is that just for aftermarket?

[ducpainter]

I read online they could be bigger though, or is that just for aftermarket?

Yes.

Typical carb venturi for a 900 w/ FCR's is 41mm

[mxgrant185]

So how exactly can I tell or measure the carbs to find out? And do other displacements use the same size?

[Howie]

You could measure the venturi with an inside mic or a bore gauge, but, as you have been told it is a 38.  All Monsters use a 38, different jetting for different applications is the difference.  The size is also indicated in the model#, BDST38 - ****, the last four digits being the application.

[mxgrant185]

Mine is reading DUC B132 K5Y1? I bought this bike used and have no idea what has been done to it previously

[Ddan]

Those are the stock carbs