These are the 64/32/9 and 64/32/10 BING carburetors. They were standard issue on the R75/5 BMWs back in the early 70’s. From what Siebenrock says, they will work just fine with their power/performance upgrade piston/cylinder kit. They may need different jetting but I’ll cross that bridge when I mount them to an assembled engine.

I finally got around to looking into them. Holy crap, they are used and abused. I have two sets, one from the parts bike and another from our ‘main’ bike.
One set has been modified by a previous owner who added vacuum ports on them. The ports look bad, and who knows if they are completely sealed so i’m going to shy away from using that set of carbs. Too risky.

The other set is nasty but can be rebuilt. The diaphragms are OK but everything else leads me to believe they have never been rebuilt before. The only drawback to using these carbs is that the BING nameplates are trashed and replacing them is a tricky job that requires precisely drilling out each metal nail. It may require many hours and machine work that I’m uncertain about. I’m thinking that I will polish the crap out of those plates instead.

Here is the carb, dirty and ready for a new life:

Here goes:

Choke removed, needles coming out:

Everything apart (an unofficial diagram):

The second carb had a slight issue… One of the butterfly screw heads turned to putty and stripped when I tried to remove it. I had to drill it out, and bastardize some parts from the second set of carbs to replace the pivot arm that the butterfly attaches to.

I was lucky enough to receive an Ultrasonic cleaner as a gift earlier in the year. I LOVE the idea of NOT using a highly chemical, messy, toxic carb cleaner kit. So I poured a bit of simple green in the tank, a small dab of laundry soap and some hot water.

After about 20 minutes of vibrations, the carbs came out nice and clean.
Before:

After:

Next steps:
Time to buy the complete BING rebuild kit for $210. And maybe blast these carbs for an even cleaner surface.