Hi Terry,it's not hard to overhaul a carb, I've done it twice with good success. You can by an overhaul kit and replace all the  wear parts in it. Here is where I bought my kit.http://www.bingcarburetor.com/bmw/bmwcvkits.html If your carbs has never been serviced in 65000 miles, it worth doing this. You might not need the floats, but if you want peace of mind, just do the lot.  You might end up needing new screws for the lid, because the old ones may need to be drilled out if, they are stuck. Replace them with Allen heads screws. You will need some carb cleaner as well. Be careful with that stuff, it's evil. Use gloves and work in a well ventilated area, outside is good. There are lots of little passages that you'll need to spray the stuff into, so wear eye protection as well. Other than that, it's straight forward. Do only one at a time, so you don't mix up parts and you have one for reference. It takes about 1 1/2 hours to do one. I can talk you through it if you get stuck. It's helpful to have a dental scraper to put the new o-rings on, but a bit of floss will do the trick and you can't poke yourself with the floss. Hope this helps.Here is a link with some pictures http://bmwor.org.nz/forum/index.php/topic,1222.msg6461.html#msg6461 This reminded me that I ended up changing the springs as well. One of them had been rubbing and was almost snapped in half. I am talking about the long, large soft one. The ones that operate the cables can rust through, but if they are not, you can reuse them. After this, the fuel consumption went down from 8litres per 100km to 6 litres per 100km. So the kit paid for itself in a relatively short time.

I've done two pairs now. There are pretty detailed instructions available. If you are going to replace the o-ring on the butterfly-valve shaft, you'll need to be aware that the two screws holding the disk are peened on, and you'll need to file some of the thread off. It's important to peen them again on re-assembly, otherwise, if a screw comes loose, it will be ingested by the engine.  Good luck, just go slow and methodical and you will be OK.