More strength to you mate! These days it seems happiness is a rare phenomenon and is well worth the effort to keep it.

Have you talked to others with EFI bikes, do they get the problem or is it just the JH600s? The thread suggests it is both fuel and EFI but I think fuel would show up on other such machines. Is there a carby version of that machine or would that be too hard?

I run my (carburetored) Kinlon on anything handy, usually regular, but I have used premium, and even ethanol mix with no stalling problems. The manufacturers say use 'premium' in it but others on the forum have told me that regular in Aus is same as premium over there! Sometimes when I am broke I even top it up with spare 2 stroke mix I have prepared for the chainsaw and I haven't noticed any running problems. You might get some pinking with bad fuel, or gunked up carbies or injectors but the stalling in certain rev ranges only that you get certainly suggests EFI. In my car I found that the sensors in the fuel flow area played up when I took out the air filter and it misses then in some very limited rev ranges, when throttling either up and down in all gears. I don't think Pfaelzer mentioned that problem occuring seriously on all his trips so it might be an idea to compare the EFI model/versions on the bikes that stall with those that don't?