Bing Carburetor Differences

[Bob_Roller]

Removed the carbs from the LS today, disassembled them for a good cleaning, surprisingly, they were in good shape, but some o-rings are in need of replacement .

When I had the slide out to look at the rubber diaphragm, I noticed a common screwdriver slot where the needle sits, removed the screw, and the needle comes right out .

About .001% the effort that was needed to replace the needles on my '81 R65, it had what looked like a 6 point star washer and a hair spring clip that held the needle in place .

[Barry]

In my research looking into how to fine tune the mid range I came across this type of fixing on later Carbs. I wish mine were like that it might have been possible to shim the needle.  

[montmil]

Evidently Bing tried several different ideas in securing the jet needle. Some seemed to have been better than others. You might contact the Bing agency in Kansas for the full story.

Monte

[Ed Miller]

The LS carbs I bought off ebay fastened like that, too, Bob.  I like it better, but since I was only replacing my right side carb I just swapped my original slide assembly and all that over to the new carb.  Maybe some day I'll swap both the LS slides into the carbs on the bike, I don't know.  No need, I think the needles last a long time.

[montmil]

... No need, I think the needles last a long time.

Originally, most of the Bings had brass needles. They did wear after a time and change the fuel delivery a little bit. Just enough to frustrate a tuner. Replacement needle these days are steel. Now, the needles stay in great condition but they wear out the needle jet. Six to one or half a dozen to the other. Whatcha gonna do?

Monte

[Bob_Roller]

Does anybody know anything about the numbering system f carb jets  ?

On a jet, the larger the numerical value, the larger the orifice ?

I was just looking at the Bing manual, and noticed that most of the needles and jets are different between the 64-32-325/326 carbs on the '81 R65, and the 64-32-335/336 carbs on the '84 LS .

The slides and even the float bowls are different numbers .

[Barry]

The needle jet size i.e. 2.66 is the bore dia in mm.  I made up a 2.66 mm dia mandrel to measure mine for wear and could detect very little.  

Main jet sizes I'm not sure about but yes bigger number = larger bore.

[Ed Miller]

I noticed that too, Bob.  Wish I could remember what year LS my new carbs were from.  I don't know of any difference in the motors that would make the different jets necessary.  I wonder if Bing could tell us.  

...the agency, not the member of this forum!  

[Bob_Roller]

I found a set of 138 main jets in the spares I got with the LS, I'm going to install them in the '81, and see if I can get any better fuel mileage .

With 10% ethanol in the fuel supply, I've gone from 200-225 miles to reserve with non-alcohol fuel, to 200 miles to reserve with the 10% ethanol .

All of the jets and needles are smaller on the '84 LS carbs, than they are on the '81 R65 carbs .