Would anybody advise about how much any engine should release engine oil through the breather pipe,there is a new top end on my 1VJ model ,on a long run there is a small amount of oil released into air box through the breather pipe,nothing too serious,would this be considered normal. Also can anybody recommend a fuel additive or fuel conditioner for an XT600,is it necessary to add something to the fuel in UK of N.Africa?.

There were always small amounts of oil in the airbox on my 1VJ Tenere, but it never caused the engine to run badly. I assumed that it was just a vapour from the breather as the exhaust didn't smoke. My opinion: if you've just rebuilt the top end including piston/rings/rebore then there may be pressure escaping between the rings and bore as the top end runs in. This may cause excess oil pressure causing the oil to escape through the breather. Alternatively if you've overfilled the engine then this might also cause the escape.

as ian said, there are mainly two reasons for oil in the air box. if it is due to the pressure in the crankcase, the amount of oil to be found in the air-box depends mainly on the play of the piston(big play - higher pressure).
klaus@xt600.de