(GPZ, I'm definitely NOT lumping you in this category....; just making a commentary.)
I'm always intrigued by "turn the key and go" people. They think every time they get on or in a vehicle and hit the starter, it should just automatically go. (Hmmm, I'm married to one.) Jeeesh. Modern electronics makes this even more common, because of increased reliability.
I'm a dispatch and maintenance supervisor for a small private tanker trucking company. About 70% of my drivers are TTK (turn the key) guys, who don't know an injector from a glow plug. I'll get calls in the middle of the night when they "break down" and attempt to walk them through McGyver type repairs so they can get going again. I carry more tools in my old Rover than they carry driving thousands of miles in a week! My point is, ANYONE can turn the key and go, on a late model motorcycle or car or truck. Hell, a monkey could do it! For ME, one of the greatest satisfactions I have in life, is an ongoing; increasing understanding of engines and mechanics to be able to get myself (or others) either back on the road, or to someone who knows plenty more than me for a repair. Most of this I learned through the backyard vehicle tear-downs and replacing items (more than once in some cases) because I wanted to avoid that "dependence-through-ignorance" thing, in the future. I enjoy, and RESPECT, people who have a similar life history and experience. It's all nuts, bolts, wires, and parts. I encourage all of you to buy some basic tools and at least change your own oil and plugs.
GPZ, you're in the zone some of us enjoy almost more than riding (thus, my earlier comment.) Yes, it's a PITA you can't TTK and go. YOU'RE trying to find out why. Stay with it; don't pay someone else and miss an opportunity to learn. We're here to help.

 

I definitely love to tinker, and I am really getting to enjoy disassembling the carburetors (over, and over, and over again). The only drawback is that I work a lot-- over 80 hours a week, with a very strange schedule. I haven't had the chance to ride for over two years, and I'd really like to get back on my bike (Jeff, it looks like you're from Ohio-- the weather here is great in the summer, but isn't that way for long!). That's why it can be pretty frustrating when I think I've fixed the problem, and seem to be back to square one (BTW I do change my own oil-- not quite THAT much of a novice).

Anyway, back to the bike. I disassembled the carbs a couple of days ago-- it seems that the needles weren't sitting well (3 out of 4). The butterfly valves seemed OK (approximately opened the same amount at idle adjustment, none stuck, etc). Jets were not clogged. Service fuel level normal for all bowls. Put the carbs back on the bike. The engine turns over and runs well, only at 8000 RPM, regardless of idle cable adjustment.

When I tore down the carbs I reset the idle screw to 2 turns (recommended by the service manual)-- previously they had been variable set between 2.5-3.5 turns. I think this may be the problem -- certainly would explain why it seems to run too rich.

Within a few days I'm going to pull the carbs off again and adjust the idle screw. Anything else I should look for while I'm in there? I'm getting to know the carburetors pretty well now, I think I've checked pretty much everything that could be a problem. Also, and rough idea of how many turns out I should adjust the idle screw? Any input is (as always) appreciated.

Thanks

 

I realized once I submitted my post that I had said "idle screw." What I meant was "pilot screw."

 

lol, I was about to tell you that you dont have to disassemble the carbs to adjust the idle screw. I have no recomendation on pilot screw settings (never touched mine) but while your in there look for debris in the carb, and ensure all the jets are properly installed, its easy to make a simple mistake in reassembly. Since it is running smoothly at 8k I doubt that that has anything to do with your problem but always good to check.

Good luck bro

 

Bike is still idling at 8000 RPM. Idle cable changes idle only about 500 RPM. I've adjusted the pilot screw without any significant effect. I think there might be a vacuum leak -- the symptoms seem to fit, so I've torn down the air cleaner, carbs, boots and I'm in the middle of conditioning the rubber parts with Armor All. Haven't been able to find any big cracks or gashes, but I'm still looking.

 

Still no go? Figured this one was fixed. Let us know how it goes brotha.