Is your "throttle stop" bolt is out all the way? I had same problem, bike would idle high when warm or after long highway run, but i was able to bring idle down by unscrewing the bolt a little. Of course next day it would make my bike die at idle until I add few turns back.
After carb sync and setting idle screw 2.5 turns out (I played with them while doing carb sync) this problem became smaller, and by now I am almost fine where the bolt is, my idle rpms are set low (bike will not idle for too long without help from throttle) but I do not have those "high rpm" problems anymore.
I think idle screw playing during carb sync made the difference, the last half-tun had a big effect on rpms. Also, I did carb sync with home-made differential manometer(bottles with water in them), I think it is the most accurate way to sync carbs.
Does that bike have a mechanical advancer? They can stick and cause this. Take the weights off and grease the pivots. Sometimes the springs can weaken too.
You said 79, it should, behind the points plate.
How about a pic of the carbs you are using now. What pilot jets does it have and what clip is the needle( the ones in the diaphragms) set at? No the bs32's are a different style of diaphragm.
Hopefully it won't come to that, but if diaphragms are in your future, my Scottish half owes it to you to share this link with you (http://www.jbmindustries.com/). Apparently a few guys on here have used and been very happy with his product.
Best of luck.
I am back on rota at work, but pulling carbs will probably be happening again soon so will post pics asap. I cant provide any jet sizes as the rest are illegible or not removable without force
Needle setting will be fothcoming with next carb pull
If you can't remove them you can't fully clean them especially pilot jets.
Actually, that is one thing i tried over the weekend out of interest. Screwed idle control right out while idle was flying away but made no difference whatsoever. The only way to get idle down was by forcing it. I could keep it running then with a little blip of throttle but as soon as i went too far (above 2.5-3000rpm) idle would fly away again.
I literally (or feel like) have tried every combination of settings to no avail
i'm too embarrassed to reveal cause but needless to say it was entirely my fault.
5 miles down the road coming up to a junction and the damn bike started revving high again and seems to be backfiring through left hand carb.Thinking it was possibly lean , Out with the tools and mixture adjusted (and lots of start-stops later) and still the backfire and high revving.