Slow return to idle after rebuild

[nilsthenomad]

Hey all,

I just spent the last two weeks rebuilding my head on my '81 750K. This was my first undertaking with such a task, so naturally I'm scared shitless that I did something wrong. I replaced my piston rings, and all the gaskets after I had bad compression on the 2nd and 3rd cylinders (turns out the 30-year-old head gasket was  rotted away and sucking air on 2 and 3).

So after two weeks of cursing and rebuilding, I finished today and started it up. It took a bit but then purred into life. Everything sounds good, but when I rev up the engine the rpms stick and only very slowly drop down to idle (or it dies). I don't know if there is anything I may have forgotten to adjust during the rebuild that could be causing this. My throttle cables and choke are behaving normally and are adjusted properly, but clearly something isn't right. it tends to stick at about 3000rpms if I rev it up above that point. Any advice would be much appreciated. Thanks in advance.

[TOOLS1]

Sounds like you have a vacuum leak. Probably the rubber boots between the carbs, and head.
TOOLS

[nilsthenomad]

Alright, i reseated my carbs and restarted her. I'm now getting a steady drop in rpms but can't seem to get it to idle. I heated the engine up and attempted to adjust the idle to find the sweet spot, but it seems that it either wants to idle super high (2 or 3000 rms) or not at all. The engine is running perfectly besides this, so this seems to be my last hurdle before I get can the bike road worthy again.

[seestheday]

Did you test for a vacuum leak by spraying a flammable aerosol around the carbs?

Did you clean the carbs? Have the carbs been sync'd? What are you air/fuel mix screws set to?