Problem solved, don't know wether to laugh or cry..

[Ugluk]

I was given an '89 gs500 early this year and figured it would be a good everyday hack for shorter rides. The story of the bike is that my buddy bought it around 8 years ago to use as a learners bike to get his license. During one of our lessons (I was teaching) his camchain tensioner failed with a resulting valve salad.
So drivers lessons turned to bike mech lessons for both of us with Haynes as instructor. Two valves were replaced and one straightened, and about six months of intermittent sessions before his girlfriend finally gave him to much trouble and the bike ended up behind a barn covered by a tarp.
There it sat, gathering dust and happily decomposing until januari this year when my buddy asked me if I wanted it as it had no real value and he would never be able to get it running.

The battery was deader than the dodo, and most of the rubber on the bike was crumbling. Both piston slide diaphragms were ripped, probably due to some violent backfiring in early starting attempts. A lot of rust miscolor the frame.

A new battery, diaphragms, new hoses correctly routed and extensive carb and jet cleaning and I did actually get it to start and sort of run.
To make matters more complicated the bike had initially been restricted to 25kw but fixed by the guy my buddy bought it from. Therefore the bike came with an additional set of slides with two holes and I had no idea what had been done to the carbs.

Eventually I got it driveable by raising needles and setting pilots at 1 turn out. It would seriously bog between 2k-4k when not really warm, and throttle would only work up to 3/4 twist. No changing of main jets made that last bit of throttle good.
I did however manage to tuck in good and get an indicated 100mph on 3/4 throttle.

Last night I decided I was going to see if the valves was sealing properly and upon disassembly found cams timed one notch off. 
I corrected this, reset carbs to factory and did a sync, and.. Hey!   She runs well! Responds well to throttle and sounds healthier.
Now there's just a bit of fine tuning needed.

I spent a LOT of hours fiddling unnecessarily when I assumed it was a carb problem, but on the upside I now have squeeky clean carbs.

Just felt I wanted to share this as I'm really happy now. There's few things better than finding "The Culprit"..

Wish you all the best
Conny, Sweden

[the mole]

Well done!!
I spent more of my life than I'd like to admit trying to tune a VW Kombi (after the motor was rebuilt by a "professional"). The problem.....cam one tooth off.