Carburetor Butterfly Shaft seals

[jp9094]

I organised to have a local BMW guru adjust and balance the carbs on my '83 r65 LS as I am not up to speed on carburetor tuning (my wife tells me I am deaf).
To my surprise, after he had the bike for about a half hour he called me over and pointed out that the butterfly shaft on the left carburetor going in and out on acceleration. This made proper adjustment impossible.

He suggested that the shaft seals were worn and that I needed to replace them before a proper carb tune could be done. Now here are my questions: How difficult is this to do for an "average" mechanic? Can it be done with the carb on the bike (ie. cables intact and rubbers removed?).

A superficial search online suggests there may be problems with the screws holding the butterfly in place (they need to be peened after re tightening them etc.)

Would I just be better off removing the carb and sending it out for repair? Who does this kind of work here in the US? Ant ideas folks?

Many thanks in advance.

[Bob_Roller]

The  carbs have to come off of the bike to do this job .

If the soft iron screws come out after filing down the peened area it's not a difficult process .

The screws are only used once, so they need to be repalced .

If the screws don't come out willingly, you're going to have to replace the brass shaft .

I paid $12 each for them in 2007, don't know know what prices are now, I had to replace both, of the shafts the screws were over peened and had expanded in the threads of the shaft .

There at best 2-3 very fine threads in the shaft .

Here is a business that specializes in Bing carbs .

http://www.bingcarburetor.com/index.html

[georgesgiralt]

Hello !
If he sees the shaft moving when turning the gas handle, IMHO the shafts are worn out and a new set of seals won't make a big difference (or make it on the long run).
IMHO if these shafts are worn out, it is time for a complete overhaul and new rubber all along.
You can do that provided you are careful  and do one carb at a time to have an example for assembling them back.
You'll be surprised at the shape of the old needle compared to the new one ...
Just my 2 cents.