Hello laci.
I will try to answer your question despite I am not very familiar with your type of motorcycle, the R100S, year 1980. But I think that your question is a general one, so my experiences with more recent bikes (of course more than 20 years old too) might be helpful.
First of all, do you know? did you find? did you have a look at the "Database"?
The document, made by these amazing member of this amazing forum, referring to your motorcycle should be the following one (
http://forum.2-ventiler.de/vbboard/showthread.php?15043-2-3-Vergaserkunde-Modelle-247-7-1976-1980), go to page 21. It is all in german language, it is a PDF-document, so you might be able to copy the content you need into a translator.
The general way, how I have learned it, to adjust the floater (Schwimmer) on BING's is the following:
- close your petcocks (Benzinhähne)
- remove your floating chamber (Schwimmergehäuse) on one side
- empty the floating chamber content back into your fuel tank
- go with your fingers under the floater and lift it upwards, observe the way how this little floating needle (Schwimmernadel-Ventil) is moved upwards into his housing. In this position, there should not be any flow of petrol
- now, you should have a small recipient at hand to keep under your carburator
- open the petcock, there should still not be anay flow of petrol
- now, very slow + gently, allow the floater to come down
- at a certain moment (and a well defined position of the floater), the petrol flow should start
- the correct position of the floater to allow the petrol to flow is exactly the following: when the upper horizontal line of the floater is parallel to the lower horizontal line of the carburator housing
Adjusting this position is made by slightly and gently bending this little metal tongue (Schwimmerzunge) where the floater needle (Schwimmernadel-Ventil) is reposing on.
Repeat on the other side/other carburator.
Make a check that both floating needles are opening at the same time: get a second person, and practicise the above simultaneously on both sides/carburators.
To have the correct petrol level/floater position (Schwimmerstand) is quite important, as well for good starting behaviour and for good running at idle and at load.
If you cannot get your carburators adjusted/running correctly, one thing to do is to remove both the foaters and put them on a balance. There is an exactly defined weight given for the floater. I don't know how much it is but there surely somebody will come up with the exact weight (in grams).
When removing the axles of the floater to get them free, the axles (Schwimmer-Achse) are only going in and out in one direction and both ends of this axle are different. So, don't make a mistake on this.
Hope to have given some help
Nav/Ch
