Reply To: No spark gt125r 06
Piston rings = Working on it as i myself want to stock them , hyosung is not making anymore pistons for carby bikes, as they moved on to the GV125-S EFi now (totally different engine)
Cylinders = check ebay , if you don’t see damage on yours , then ignore that but usually ask the sellers on ebay if the jugs are OK , personally i stripped some jugs off several bikes on ebay and most are untested as the engines had other bottom end issues (bad crank bearings etc) but i could not see anything on the jugs that would cause issues later so i listed them as spares / repairs , you could buy the cheapest jugs , send them to a garage to get them re-honed , buffed up or do it yourself so its super smooth.
Pistons = Best bet is to get the used ones , they will have rings you can take from. or use the pistons.
Valve Heads = Get ones that are said to be OK on ebay, saves you having to replace bent valves on yours if its causing compression issues.
Tear down first and see what’s going on with yours , if you ever put it back together , new-gaskets are a must!
Replacement engine is a last resort , don’t give up on her, you just found out the true reason why it struggled to start , the ex-keepers need a slap for abusing it.