I'm still debating. I do a search on this forum, and all that does is muddy the situation. My thought is whether to use a Wiseco piston kit or go with OEM parts. If OEM, I'm finding multiple part numbers for my bike that has the "A" cylinder. With Wiseco, there is no A, or B.
I can actually get the OEM stuff a tad cheaper than I can Wiseco (OEM coming from oem.honda-factoryparts.com and Wiseco figured at RockymountainATV).
I am leaning towards the wiseco kit, and adding piston pin bearing (I figure cheap insurance). I already have the cometic top end gasket set. I am also leaning towards the Boyesen Pro Stock Carbon Fiber reads for 38 bucks. My 99 CR125 appears to be un touched other than a FMF fatty and Shorty silencer. The jetting, needle and air screw where still at the facotry settings, which were way different than what FMF recommended for this bike with their pipe. I lowered the needle, but haven't changed the jetting. I give it a good ride last night and then pulled the plug. The plug, with the lowered needle, looks awesome, it was quite a bit dryer and was actually brown as oppsed to usually wet and black. I also tested compression again after a good ride and after I had de-carboned the exhaust valves (which weren't that bad), and I am still at 120 PSI.
just looking throught the exhaust port, my piston and cylinder looked great. I am planning to just have my local machine shop run a ball hone down the cylinder to clean it as recommended and then simply install a standard piston and ring. Once that is done, I may play with the jetting and go back to the OEM plug which is a BR9EG (I am currently running a B8ES with great success, I fouled the original plug the first time I tried to start the bike and replaced that plug. Beend running on the same plug for over 6 hours of riding now with mostly first kick starts).