Are my pilot jets too big?

Having virtually no documentation and no luck finding recommended manufacturer information, I gotta ask the experienced jetting crowd here.
My 1975 XS runs incredibly rich at idle. Eye-burning rich. Spark plugs both covered in black soot. I popped the carbs off and found that both have a 47.5 pilot jet.
That sounds a little too high for my locale (Texas, so high temperatures, high humidity and elevation about 700' MSL).
What pilot jets sound correct for me?

Yes, your pilots are a size larger than stock ......

Perfect, thank you. Plus my adjustment screws were 2 out.

While I was searching for the pilot jet size here, I came across 27.5 (for a 1978 motor).
What is reason for the large jet size difference between different years? Inquisitive mind wants to know and learn.
Thank you.

Yes, it has to do with how air is delivered to the pilot jet and what it flows. The BS30/96 type pilots (like yours), sized in the 40s, have the air delivered down an angled passageway to the bottom of the jet. The jet flows the resulting fuel/air mix. The VM22/210 type pilot has the air delivered to the top of the jet, above it, and it flows straight fuel. That's why it's sized so much smaller (in the mid to upper 20s) .....



Even though the two jet types will physically interchange, you can't do that. You must match the jet type to the correct bowl type. Also, the two jet types differ internally by which end of the jet the metering orifice is on. This makes it pretty easy to identify the type you have just by looking at it's bottom .....

Also, the chart 5twins put up shows 'em by model year of the bike. Lovely if you're the original owner. Problem is the carbs might be off a different year bike. Shit happens over the years. You need to verify what year carbs you have and go by that model year.

5T, thank you for the nicely detailed, yet succinct explanation. I am used to the VM22 style jet (and have a few sizes at home) but the BS30 took me by surprise. I learned something new today, thank you.