Carb Float and Air questions

[grumpyone]

Morning all; Got a question this morning that we could use some help with.
Rebuilt the carbs on our 86 R80 this weekend and in the process realized there was a lack of info on my part for a couple of items.
First on carbs floats I have always held them one way and measured a specific point then turned them over and measured a certain point. These points were always given in the instructions with the kit as well as the deminsions to bend them to. There were no such info and I could find no such info on the float setting on these . Carbs are Bing 64/32/357 - and 8
Also On the needle air valve I found that it is a starting point of 3/4 turn out from rebuild we are at 6500 ft elevation would this be a little less say 1/2 turn out for the higher elev.??
One more thing the bing kit we got from our bmw dealer had the std o rings and they are very close in size How critical is the o ring size on the air adj screw?? is there any way to check it is doing its job?
Thanks for the help
Jim and Esther
PS any other tips appreciated ::)) :ear

[20774]

RE: Floats - the old aftermarket manuals show a diagram that to set the float height, you turn the carb upside down and let the float settle onto the needle. The goal was to have the float body (actually a line on the float) to be parallel with the carb bowl flange with the float tang made contact with the needle. What you really want is a specific amount of fuel to be in the bowl when the float shuts off the flow. The depth of fuel is around 22-24mm...might be something different for your carbs...Snowbum has a discussion on this. The procedure is to turn the petcocks on, let the bowl fill, then turn the petcocks off. Then remove the float bowl and measure the depth of the fuel. Adjust the float tang accordingly.

Re: Air valve - actually this valve controls a gas circuit rather than air. Turning it in leans things out by shutting off the gas. These are initial settings anyway...you have to find the right settings during the carb synch process.

Re: O-rings - all the o-rings are critical. Is the confusion that you might be using the wrong one for the given area of the carb? The kits from Bing are quite clear as to which to use. It's packaging says:

- Biggest - jet stock
- Next down - throttle shaft
- Green - choke disk
- 4 small - idle jet and idle air screw

If the o-ring is not doing it's job, it might suck air. You could also turn it as part of the carb synch and turning makes no difference in the way the carb runs (it could also mean clogged passages). If you temporarily remove the air valve and find the o-ring shredded, then it wasn't lubed before inserting and now isn't working.

[grumpyone]

Thanks Kurt
The confusion was the four small o rings for the carb looked like two small and two smaller all four must be the same. Thus the two places I was wondering about use the same size o rings the air needle and idol screw. Or i guess you mention it is not an air screw but a gas screw but that is where I was confused.
Talked to bing and they said first buy the book ; I did then they told me to set float level and then start the screw on the bottom at 1/2 turn out which is not where mine is I have it one turn out so will change that.
I got to set up the sync process this evening and see if I can ground out the alternating cyls and tell a big difference and then it should run a little better. I removed the california stuff this weekend and capped the vac pipes on the bottom of the carb.
thanks again; Stay warm down there now ::))

:nra

Jim and Esther

Plays with guns for a living