Hi again All! This is the same 2T scooter in my earlier post that has been "revving." Piston guy was right, in that we found the bottom of the piston burred and 2 areas of the bottom side of the piston concave. The cylinder has some scoring. And, we found one ring NOT seated correctly. And - it's a 80cc Bore Kit.
History: guy buys the scooter and told it only needs a carb. They ask us to repair stating that they only replaced the carb. Once we get it started, it Revs - Later we find out his "mechanic" uncle also replaced the jug. I ask them to bring it the old parts. Their jug is way worse, burnt, rings seized, etc.
So - here's where I am all ears. Do I replace the jug kit (P4S 169-405) "correctly" and "all" should be fine?
Or ---- is there something I (my mechanic) should be thinking about here???
My point, did the uncle probably not seat the ring correctly or, did he maybe do it all correctly and there is something else causing this -- Like what?
look you have to blame work man ship, look if some one came in and said he needs a carburetor put on and get down the road and rear end fall off who is blamed owner he told him what was broken, beware.
Ok, she seized or stuck Again because you have a Massive Air leak. Runaway Throttle is a Air leak on your 2-T, and you'll Stick a Piston every time unless you Fix the problem, the Air Leak.. Either Crank Seals, Intake Spigot or Case Halves themselves, just put the crank seals in there cheap and that should eliminate that possible air leak source, just not worth the time to get a accurate test..
I was born with micrometers in my hands so even if you posted pictures of your piston and cylinder I could not predict if either is in any spec at all. even in my hands, I Don't have Calibrated Eyeballs or Elbow's so Measuring is a must.. You bet bet is Fix the Air Leak then buy a new Cylinder and Piston Assembly, its you best long term bet. If your thinking of using either cylinder scored, your mech may want to "hone" out the scuffed bore, you need the correct type of hone then when you Hone out those scratches all nice and pretty you made your Bore Larger so you will have More Piston to cylinder clearance, That is Not Good.. A piston Scuffed has most likely (bet the house) Lost its Temper and has suffered "Skirt Crush" and has lost its size even tho to the eye looks good. Once the Temper is lost she will seize, scuff, stick or grenade in short order.