1983 GS750e carb main jet and O-rings

[maxredline]

I have a very sweet 83 GS750e. The only mod is a period correct Vance and Hines 4 into 1 pipe. I didn't realize how loud the pipe was but I totally rebuilt is with ceramic packing and paint. The engine ran fine but I figure it is running a little lean. Near the end of the summer the carbs engine was sputtering on throttle until hot then started surging. I now have the carbs apart and am chemical cleaning. I am still trying to figure out the main jet sizing. Stock is 117 so I figure going up 2 if that is possible but 120 should do. From what I have read the jet type is a small round style. I do not know if this is true or not so I am stalled on this point. I am also stalled on mixture screw O-rings.
I have read to install a 2mm washer on the main needle to richen that circuit up so I plan on doing that if I can not find a larger main jet.
Any information that can clear this up for me would be greatly appreciated.

[Nessism]

Read this... https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

Towards the back, there is information on how to lift the needle. Hint: putting small washers under the needle clip won't lift the needle.

Regarding pods, you will save a bunch of time and trial and error if you buy either a Dynojet kit, or some of member Zed's "air correction" jets. Oh, and make sure your pods are not the cheap junk Emgo/chinesium cheepies. Get proper K&N's, UNI filters, or similar.

Lastly, the main jets should be the N100.604 size

[KiwiAlfa156]

Hi there, can you give a little more detail on what throttle position/operation (constant, snapped open and held WFO, rolled-on?), the rev range and and under what load the bike was misbehaving? Different fuel circuits take charge at different loads and rpm and with the CV carbs fitted to an 83' the throttle only indirectly controls the position of the slide and thus the operation of needle/needle jet and main jet. Understanding the exact conditions under which the bad metering occurs can go a long way to determining what to look at.

Have you tried the carbs running in the bike after cleaning to see if that fixed the issue? Or are you looking to re-jet as the carbs are apart on the bench? You said "the engine ran fine" so was wondering if anything happened or was done to cause the spluttering and surging. Or has this always been a niggling problem?