Good Morning gggGary & 2M -
Some interesting and positive developments last night.
gggGary - I stopped at the local auto parts store for the plugs. Naturally, they didn't have them. Our local auto parts store is a great place for air fresheners though!
They're having them transferred from another store and I should have them today.
I bought both BP7ES & BP8ES being that I have no history with this bike and don't know what it's going to react best to.
They'll become a part of a test ride I'm hoping to do after work today.
2M - I never thought to be listening specifically for valve noises. I'm sure that if a clatter developed beyond what I was used to hearing since the initial startup of the motor I would've noticed. But I'm also sure that I'm not good enough to notice a subtle improvement without it being my focus... especially if it were over a lengthy period of time.
However, you might very well be on to something here!
As you've seen, the motor (carburetor) started performing better after my 10 mile ride two days ago... and for no obvious reason.
Last night I didn't ride the bike again, but what I did do was to get it warmed up and then began the leak detection process using the propane. And it turned up nothing.
Then, still wanting to prove out beyond any doubt that there was or was not a leak, and because the "propane test" was new to me, I went back to spraying with the starter fluid. And it turned up nothing.
However, as the bike was idling I sensed that it appeared to be smoother than when I started it and it was definitely smoother than in recent history. Any time that I "blipped" the throttle it reacted instantly & very smoothly. And most importantly it reacted the same if I just "blipped" the right carburetor. And no snap, crackle & pop!
Just like after my ride of a couple of days ago the right carb seemed to be operating... but now even the exhaust tone was "better".
I removed left plug wire and it was idling fine (but a bit fast) on the right cylinder only!!!
So, I began the process (again) of alternating cylinder operation and adjusting the idle speeds of each carburetor.
Left cylinder (which was never a problem) will idle at less than 1k without issue. I can get it down to about 800rpm.
Right cylinder (the problem child) I couldn't get to idle at less than 1k without stalling.
They are currently balanced as best I can get them and it sounds and reacts (while stationary) like a different machine.
Operating on both carbs together it'll idle at a smooth 1500rpm.
And now the most important thing....
TURNING THE MIXTURE SCREW ACTUALLY BEGAN MAKING A DIFFERENCE!!!!!
Now, I know this isn't the best test, but look at the plugs....
Right cylinder for the first time in this journey is burning rich! I'll take it! I needed a battle win.
So, being that there is no apparent reason as to why the carburetor is suddenly beginning to cooperate it may very well have been or is a stuck/lazy valve that is freeing itself up. Who knows? The bike did sit for over 20yrs.
So, we have a (positively) developing story here.
I'm anxious to pick up the new plugs and take the bike for a ride later today to see if this positive development sticks and/or continues to improve.
Pete