I am kind of seeing 2 things going on (at least from what I see in the picture angle) , it looks to me like the left Rocker arm contact point is worn , and (again this could be just the angle)
Possibly, I don't have a new one to compare to but will try seeking some images. With that side I would think if the contact point was worn then I would have less of a tight clearance issue (due to worn rocker).
I am kind of seeing 2 things going on (at least from what I see in the picture angle) , it looks to me like the left Rocker arm contact point is worn , and (again this could be just the angle) it looks like the right spring retainer is different from the left
Will look at this tomorrow and pull the intake buckets to compare.
but if you are saying the rocker is touching the retainer then that falls back to the wrong retainer on the right Exhaust valve ....
The rocker is NOT touching the retainer. The feeler gauge touches the retainer instead of the shim since the shim is just about parallel or lower than the retainer. Any shim size lower than the current ones will not change the readings one bit since the feeler gauge will always have the same contact with the retainer.
With that said, I did try something a moment ago. I trimmed a spare feeler set so the width was that of the shim, no wider. Now, I am able to position the feeler so it only touched the shim and NOT the retainer. It seems my clearance with this method is in spec at .010".
Without knowing any history on the bike it is tough. IF I find the retainers aren't mixed up, I am going to run it with the current shims. I was able to get the intake valves in spec easily.
Fact is, to be 100% confident with the longevity of this bike, the head will have to be re-worked. With that of course I would definitely want to check the piston/rings/cylinder and most likely replace the piston/rings. With that there is several hundreds already, would be stupid not to do crank/lower bearings and associated parts. Turns into $1000+ easily on an already 6 year old bike.
An OEM crank for this bike is $300. To put it in perspective an OEM crank for a 2007 CR125 is $150.
Me thinks I may be riding a potential ticking time bomb. I do very much miss the smell of premix!