Hi all!
I need a Mikuni VM24SH carb for a 1973 Yamaha 175 CT3. The old carb I have is marked 314 E1 but I’m not able to confirm if that’s right or if it should be a 316 E3. Any insight and available carbs is appreciated. 
Bob

Hey Bob, I have the same bike and had to replace a chinese carb. The manual says the carb # for the CT3 is 314 E1. There is a good manual in the tech library for this bike.
Cheers 

Nice job on the ID of the carb and picture of that tiny little number!

Yours looks pretty nice.  Most of the time the original carb can be made to work but sometimes something "catastrophic" happens.  Last weekend I found a shopping bag when I was cleaning up and it had a couple used At/CT carbs in it.  I'll check tonight and see which ones.

P.S.  314 is the model code for the later CT series.  316 is the model code for the later AT series.  The "E" number is generally a jetting revision number.  Yamaha had several updates to the jetting on the later CT...  any should run okay with the higher E numbers generally being the latest revisions...  for example 314 E1, 314 E2, 314 E3 with E3 being the latest revision.

In a pinch you could use a 314 carb body from an AT if you swapped over all the jetting from the CT.

Thanks guys. Would a 316 E3 work in the CT3? Can you direct me to a manual that shows this info on what model VM24SH went with what bike? Much appreciated!

Thx Mike. I’ve seen the repair manuals but not anything on carbs that shows model numbers.  I’ll keep looking though. 
Regards, 
Bob

Thx Mark. Please let me know if you find a carb that will work!
Best,
Bob

I will see if i can find the jetting literature and will look at the carbs later.

Guys, the VM24SH 314 E1 carb I have looks good outside but inside it’s a wreck and can’t be reused. See pics below. I’d like to find another 314 if possible but I’m trying to understand if I can use any VM24SH body and just swap out and reuse the correct jetting parts from the old carb (or new parts that are correct). I have an option to get a 316 E3 model body and am trying to understand if that can work if I just swapped out the jets. I’ve looked all through this websites technical info but can’t seem to find anything on carb model numbers and what bikes they go to. Again, thanks for the help.

Your carb would look totally different if you put it through an ultrasonic bath .
It's very likely not a lost cause .

I agree it's probably okay. 

I already answered your questions in post #3 on swapping to the 316 and what the numbers mean.