how can i fix my yamaha dtr 125" 1990?

hi there could anyone help ive got pittin on head and top of piston on my dtr,1990 im takin engine apart 2 do seals etc ,any tips as been long time since had one apart 2oyears lol,also my casing has split at gear select,ive seen one 4sale its a 1999 will it fit ?or anyone got one 4sale?07522132384 thx tommy

tommyboat@hotmail.co.uk
March 2009