SO..I had the flooding carb /petcock thing (again) on my latest 81 750 ltd .
Now Ive had 4 of these machines and had this prob twice . 1st time it seemed to be only when on side stand (as it appears many others have had) . Well before i resolved it I sold the bike and I DID advise new owner of the problem . which he seemed ok with .
Anyways .. 2nd time is my latest 750 ltd .
After checking the internet for solutions and finding myself on here . it didnt get me anywhere fast . offered solutions didnt work (for me)
So what i did was send off for new petcock kit . stripped ,cleaned and replaced all rubber bits with new . refitted tank. A a aannnd ..FFS..!! same problem .!!
BUT after stripping petcock 2nd time I noticed in the plastic centre base plate for the diaphragms on one side is a thin tiny 1mm channel in the moulding from outside to inside . I suspect to balance the vacuum whilst running and to equalise /negate the vacuum when engine switched off.
Did I suspect that this tiny easily missable detail might (if blocked by shit ) cause a remaining constant vacuum even after switch off ..? HELL YES ..!!
Also a badly aligned diaphragm on re-assembly will cause rubber Diaphragm to block this tiny air conduit.
SO...!! yepp after cleaning out this little channel and ensuring diaphragm fitted precisely .. It solved my carb overflow problem . Why it only did it on side stand ..? Don't know . Do I have a flooding carb due to faulty petcock ...NO. !!
Try it yr self see if it works for you , and good luck
Did you buy OEM Kawasaki parts to rebuild the petcock? In my experience that's the only way to go. Aftermarket petcock rebuild kits are quite often JUNK, similar to carb rebuild kits. I rebuilt my 750/4 petcock with OEM parts and it works perfectly.