DRZ400SM - physical difference between the FCR 39mm & 41mm?

[MotoJunkii]

So I bought a used DRZ400SM last summer and have noticed a few upgrades the the previous owner invested in. Unfortunately I bought it from a dealer, so there's no way to confirm the history and some of the internal upgrades, but one I know the stock carb was swapped out. Is there an easy way to tell the difference between the 39mm and 41mm FCR? I'm trying to figure out which one I have. 

[Smias]

Carb body are the same on 39 & 41 , take some good close up carb pics from the left side .

Do you know what fcr you have ?

Fcr or FcrMX ?

[Chas_M]

Yes, the carb bodies are the same (37,39,40 & 41mm).  The best way to tell is by measuring the internal venturi (bore size}.

[MotoJunkii]

Carb body are the same on 39 & 41 , take some good close up carb pics from the left side .

Do you know what fcr you have ?

Fcr or FcrMX ?

 

I have no idea. I'm inclined to say FcrMX, but I'm not sure. here's a picture. Can anyone confirm for me?

 

[Smias]

It's an FcrMX for sure , direct from Keihin/Sudco .

 

See the code(G A40?? i can't see it very good..) it has on the left side on the carb body above the carb bowl and check it with Sudco .

[MotoJunkii]

It's an FcrMX for sure , direct from Keihin/Sudco .

 

See the code(G A40?? i can't see it very good..) it has on the left side on the carb body above the carb bowl and check it with Sudco .

 

perfect! Thanks for the tip!

[themotoviking]

Just curious, what is the blue thing all the carb overflow tubes go into?

[William1]

Just curious, what is the blue thing all the carb overflow tubes go into?

A collector that typically would go to a catch can.Though merging all the vent tubes somewhat negates the value of the uppers.

[themotoviking]

A collector that typically would go to a catch can.Though merging all the vent tubes somewhat negates the value of the uppers.

Figured as much just curious. Thanks