No bore scope presently.
Following rebore, bike ran well and continued to after i re-torqued head and set valve clearances....must have done 6k or 7k miles since then. Some point towards end of last seaon noted the power dips. Continues now. Became aware of bit of tappet noise on left side prior to noticing power dips. Did another clearance check/adjustment but never got tapping cured.
Plugs have been quite good, brown tan, not oily or sooty. Running needles on richest/ highest position to cure some exhaust popping.
Much like ignition problems can turn out to be fuel problems and visa versa, could your miss be something like an intermittently bad spark plug? (I had one of those that tested good outside the bike, but under compression was cutting out)
What's your ignition system? electronic? individual coils? dual coil? Have you tried any of the left to right swapping of ignition parts to see if you can make the miss follow the swap??
In regards to the ticking and any thoughts about cam lobe wear, you can do a valve adjustment and observe where the adjusters fall in the rocker arm to see if the adjusters are locked at the same thread depth. That gives a decent idea whether the cam lobe heights are drastically different all of a sudden. (If you recall Semitone's recent thread, he later remarked that his adjusters were locked in vastly different positions which was a clue to his valve train being his issue)
Maybe pull the plugs and roll the bike over to inspect the valves going up and down. Maybe a sticky valve is causing the occasional miss. It would make sense. Ocassionally you get a miss, your compression is slightly less on one side and it's making a ticking sound. Maybe unburned fuel is depositing on the valve seat from a miss and now it' s showing up as a poorly sealed valve....
After you do all this observational diagnosis, you know what the next step is... a look inside.
Or you could buy a cheap bore scope and worm it up the oil drain plug hole to look at the cam lobes and followers, and then reposition it to see the bottom half of the bores. You can look at the top of the bores through the plug holes. From what I'm told they do a decent job for not all that much money. (but I don't own one so I'm just going on hearsay)
