I would agree with your decision. I recall reading a reply from a master tech in one of the magazines concerning Honda's clearance specs on shim under bucket engines and in particular the ST1300. The gist to the reply was that a clearance that was a little on the loose side may be caused by a bit of carbon on the valve seat or valve face that temporarily increased the clearance between cam lifter and bucket. To reduce the clearance by changing shims treats the symptom and not the cause. If the carbon blows off in due course the readjusted valve is now too tight and will be until the valves are checked again. The tech suggested a shock treatment of carbon removal product like Chevron Techron, StarTron, Seafoam or other carbon cleaner and not to worry about it.
Back when I was a teenager, one of the methods used by automobile shade tree mechanics to clean up valve deposits was to take the air cleaner off and slowly dribble automatic transmission fluid directly into the carbs while the engine was running. Don't know if it really worked or not but that's what "everybody" was doing. It was kinda fun because it created one heck of a lot of smoke
. Now, flash forward to today and I find this same method being recommended on the internet for fuel injected engines but instead of using ATF, you use Seafoam.
HERE's just one of many links I found for the Seafoam shock treatment method for FI engines. The main difference with this new method is that you use a vacuum line to introduce Seafoam into the upper cylinder. I'll state right now that I'd only try this if my intake valves were so seriously out of spec on the high end that I was on the verge of pulling the heads. God only knows what sort of havoc such a concentrated hit of Seafoam would do to the catalytic converter.
I ran Seafoam in my gas a couple of years ago when I was having acceleration problems (turned out to be due to rust in the lower tank) but think I'll start using it again maybe once a month or so and see if the intake valve clearace migrates back to specs by the time of the next valve check.
What I really need to do is to take a nice, long, high speed run through west Texas on I-10 where the speed limit is 80 mph for about a 500 mile stretch. Maybe that would help burn off any carbon deposits???
