Carbs dimensions help!!

Hello. I bought some carbs on ebay for an XJ550, and they arrived intact. But on the throttle body there's this little number "130" and on my other carbs (that i broke) there was written "125", and i can notice by looking at the net carbs that they are a little bit bigger. Is it a problem? Will they work? They are both MIKUNI and they both fit on the bike...
Thank you for your help!

 

A pic would really help us out. If you could post a pic of both carbs side by side and with the numbers. If they look the same, mount the same and have the same throttle and choke cable placements. Air intake and connection to head must be the same, they fit in the boots. Jetting would be the issue I would look at.

You mentioned "at the net" the carbs were bigger, please explain.

 

I'm sorry, i wanted to say "at the new". As soon as I go to my garage i'll send you some pics. Thank you so much for your help.

 

First pic: the new ones
Secondo pic: the old ones

on the nose ones have also a gas thing on the upper part of the throttle body.

 

Here is a link to the "Church of clean" I hope that it helps you out. In the information, there should be a way to ID your carbs better. There is a numer on the side of the carb above the float. That is the number you need to look at to ID the carbs.

https://xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

If I recall the xj550 carbs are smaller than the fj600 - both Mikunis, similar in most ways. The jetting will be different. Have you not measured across the opening at the engine end?

 

Do you think that these are for the fj600? Does it change something? Do they still run fine? (I'm sorry, i'm a noob in terms of carburetors..) What is the jetting?

 

Are you capable of using a ruler - first step...

 

I saw that the jettings are 122.5 and 40.

 

as soon as I go to the garage i'll tell you.

 

Fz600 or YX600 carbs are same spacing as XJ550. FJ600 are spaced same as XJ650-900

 

I'm not sure thats true.. BS28( XJ550), BS30 (YX600/FZ600) and BS32 (XJ600 Euro 51J and maybe late FJ600 US) have teh same sized head and thus the intake
spacing is the same, although the BS32s are physcially BIGGER and you will need the matching airbox rubbbere and double-jointed fingers to fit them, to a 55o .

I wonder if OP actuially has a slightly smaller capacity XJ.. like a 500. I have a feeling Italy imposed some tarif restriction on bikes over 500 and a special was built
to get through them.. If so his original carb might be smaller.. The newer/bigger ones will work though I'm fairly sure. How doe the frame number look? 4V8... is Euro 550

 

My fj600 carbs are (well they were before I machined them down) bigger than xj650 carbs, but the same spacing. I never knew the 650/750 and 900 spacing was the same though.
With the fj600 airbox tucked under the xj seat they work pretty good out of the box, if anything I think the idle jets are a tad big, but I've not tried smaller ones yet.