I have just obtained a GT 550 basket case,speedo is showing 17000,engine number is 70987,vin 67893,the engine was well wrapped having stud for 15 years and turns over freely,my aim is to get the bike up and running, looking up the middle exhaust port the piston looks slightly scored! what would you advise ? head off and check bores,pots off re ring,re bore? i have done some research and believe the engines to be quite robust. thankyou for your time with this.