A few possibly relevant points to consider.
Carbs get filthy from sitting or being fed bad gas. An example is my 74 Cb550. 20 years without carb work, which I attribute to regular operation of at least once a month. Gasoline has aways been an excellent solvent, when not involved with direct human contact. If it is always flowing through the carbs, it keeps them pretty clean. Stop the flow and evaporation leaves deposits behind.
I believe someone has done proper work when the machine runs as intended. Idling at 1700 is not fixed, but only improved. I can't say I believe your carbs were cleaned and adjusted properly.
It is rare to find someone who is actually familiar with these bikes, rather than simply saying they are, or are one's who you'd expect to be. It's not that younger persons CAN'T be competent. It's just not likely they have ever worked on your type bike before. Or, they are just trying to make a living by spending minimal time and effort on each job and reaping maximum income from each. This may not include an understanding of how the machine (on this particular job) works. Just enough action to get the customer to pay money.
It comes down to three choices, I think. Keep paying your "trusted" mechanic until the bike performs as you'd expect. Keep trying different mechanics (and paying them) until they either actually figure it out or stumble upon replacing the part(s) that actually mend it's errant behavior. Or, learn how it works yourself. This last can serve you two ways. One, you may well be able to fix it yourself, saving some money. And two, you can converse/guide your selected mechanic into the proper area of the bike to work on.
Another point is that paper filters can't be cleaned 100%. And, they work by capturing particles in their membrane. Each cleaning leaves behind some particles and while the filter is still being effective at filtration, it gradually closes off the inlet area the engine needs to breathe in though. Further, paper is subject to distortion from water, such as humidity in the air. On a microscopic level, the fibers begin to collapse and this also reduces the inlet area for the engine. All this, means a paper filter has to be replaced periodically to restore proper performance. If you have had the bike 8 years and NOT replaced the filter, be aware that Honda recommends these filters be replaced on a yearly basis. One diagnostic check is to remove the filter, temporarily, and observe the effect on the symptom you wish to address. Worse/better gives a clue to correct diagnosis.
I only know two sure ways to determine a lean diagnosis. An exhaust gas analyzer, or reading spark plug deposits. The bike came from Honda with a tool kit that enabled spark plug removal. If Honda thought you should have these tools, why don't you? It's hard to imagine driving a bike around for any distance without a tool kit on board. I guess people are more reliant on cell phones and roadside assistance than I. Anyway, if you ever decide to look at spark plugs, here is something to compare to:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.htmlFinally, I may not be the best person to help with your bike's problems, as I don't have an example of that bike and I don't have any manuals to refer to on that bike.
One thing is certain, if that bike is ever going to be reliable/enjoyable, someone is going to have to get intimate with it. Like most acquired skills; patience, practice, and perseverance, prevails.
Best of luck with your decision.
Cheers,
