94 yzf 750 r ( Swiss )

Hi guys 10 years ago I brought a nos 94 yzf 750 from wheels international. From day one it was gutless 120 mph tops I rode it for two summers covering 2000 miles until it started to over heat in town and evaporate the fuel in the carbs. Run fine on the open road though . I then parked it up and brought another bike. I recently thought that it's to good to part with so I set about getting it back on the road and trying to fix it's faults . I Found the exup valve stuck in the closed position, and the engine would not turn over fully , on digging deeper I found 4 stuck rings and 8 stuck valves and a sump pick up full of gasket sealer (from new) the head gasket was not blown and the thermostat opens within tolerance . My question to you all is, would the stuck exup valve cause it to overheat in town and cause it to be gutless, or as it is a Swiss model is it restricted to 120 mph ??. If so does anyone know how to derestrict it ??. Also has any one ever used a pattern gasket set or is it best to stick with genuine gaskets. Regards pete.