How can you tell what carb you got?

[Nerd 10]

I have a 86' js550 and was wondering how can I tell what carb I have? I know in 86' they had 38mm and 44mm. Not sure if hull vin can tell?

 

[Joker]

Take it off and measure it

 

[silverbullet]

The top of it where the Flame arrestor goes will either have 3 or 4 holes.. 3 is the 38...