Can anybody tell me what the original needle set is?

Thanks for posting a photo.  Are you looking for the slide needle or the float needle and seat?

That's not a USA paint scheme.  Are you outside the US?  If so, where? 

First three digits of VIN?  Carb stamping number?

I think that Gerry is in Germany.

Thx for helping me >>> slide needle.
>>> Gr8uncleal is right: I´m located in Germany.
>>> we are talking about a CT1...
>>> it´s a Mikuni but I found no stamp. See fotos, maybe it will help.

Thx for helping me

CT1 was definitely a Euro model...  probably has VIN bracketed by "*" symbols?  Most literature is for USA models.

Two things that could help:

Look closely at carb body on side opposite choke knob.  Often there will be a flat spot with tiny numbers.  They will identify the carb (Yours won't have the hose shown in the picture, that started in 1976)

Remove the brass needle jet (threaded into bottom center of carb...  part jet needle goes into and has o-ring to seal into float bowl) and give us the numbers.  If it's the same needle jet as the US model then the slide needle is likely the same too. 

 

Model is likely a DT175 from 1974, 1975 or 1976.

It would be great if you could find a parts and service manual for it - they should be available in Germany or France.

Once you have identified the needle that you need, then look for a Mikuni dealer in Germany or the EU. If no luck, then try Motocarb or Allens here in the UK.

I don't know if this helps but USA models from 1974-76 all came with a 5G4 slide needle.

74 and 75 had an O-2 needle jet and needle clip in 3rd (middle) slot.

1976 had an O-4 needle jet and clip in 4th slot from top.

Some trivia...  in 1974 US 175's stopped using the "CT1" VIN prefix.  Other countries did not.  USA bikes started using the actual model code as the prefix which would be 443 for 1974/1975 and 559 in 1976.  Carburetors generally had the model code stamped in them...  on the later models like this it was probably something like "44360" or "55960" with the model code on carb sometimes being from a different region of the world or year model.  So not exact but still helpful if you can find number stamped in carb.