wow bud,lot of info not much substance.1 1/2 hr old.How much smoke,and when,is bike cold,choke on,does it lessen or dissapear when warm and choke off.What type and grade oil,how full is oil.I am working out my smokin prob at moment with near new xr70 I bought my kids,I`ll let you know how I go.But a couple of things bother me.#1Crap about wiseco taking longer to bed(not true) #2The scratch in bore,are they that careless they couldn`t even pack and wrap it in a rag,says a bit about competency,and if cleared up scratch,I`m guessing with a hone,did they put the said original piston in a sloppy hole.#3Compession loss,rings not fitted correctly or he put it the factory didn`t seat them correctly(wow thats a whopper)If he said after rebuild it was down on compression,and it was due to a poor seating ring,picture this,There is a hardened carbon or chrome alloy ring in a groove in a piston,clearance up and down in groove is variable but average 0.020",it has over 2/3 of its depth in this groove,it has a locator peg where the ring gaps meet.Once on piston and in bore,It has nowhere to go,and if it`s not seated(installed correctly) that hard ring goes snap,ring broken,SMOKE,bore and piston damage.Thats the compression rings.Now the oil rings are a set of 3,top is a thin credit card thickess ring and on the bottom is the same.In between is a wavey shape ring that traps oil in between the wafer ring and the gap in the wave in the middle.Now to not seat(install)correctly means at best it will smoke,but ussually if the wavey one is on top or bottom instead of between thin ones.It is softer and bends,thin ones are easily boken and smoke,let alone bore damage and so on.
It`s a 4 stroke so whipping the head off in front of him for a balls and all inspection is not easy especially for a novice.But with the seating story and the lack of obvious care they take.As well as the lack of support,and owning up to and rectifying mistakes is unexcusable.Do you have a department of fair trading in U.S. if so ring them.Is he a registered and licenced mechanic,ring the Motor Trades Association.I`m afraid that I can`t 100% say what ailes your bike,but a good educated guess would be they snapped a ring,poor install, and probably because they honed it out even more and used same piston set because they were annoyed you caught their carelessness first go and then cared even less when rectifying(if thats what you call it).$10 says it was a 1st year apprentice that actually fitted your gear and they are trying to cover.But one thing is undisputed,they scratched bore,do again,and have rebuilt,no good,take down, rebuild,no good,NOW WHAT? get in touch with someone with some obvious clout like Complaints Officer Honda Motors,fair trading dept. M.T.A. and make a noise and front them and I think after they failed to rectify the problem first go,now you have the choice of repairer and take it elsewhere and give them the bill.CHECK STATE CONSUMER LAWS FIRST.