ball bearings

one of my t 80s is imposible to ride now due to steering it feels as if its got flat tires on stripping it down i found among other things the bushes one side had given up ,while ihad got this far i decided to check out the head bearings,to cut a long story short i lost some of the bearings what i want to know is were can i get more bearings wot size and how many do i needanother of the fleet has started to over heat or it seems very hot when you touch the engine cases, checked the tappet clearance adjusted them they were a tab to tight ,put in a new plug,it starts ok and ticks over but seems to be siezeing up when flat out could this be a blocked jet or some thing more sinister

Available from Suttons http://www.gileraspares.co.uk/HTML/spares/epc2/9063/22.HTML you need parts 13 14 15 & 16

Regarding the number of bearings in case anyone else is wondering, I stripped the front end off the T80 today and there were 22each in top and bottom.