if your yb is using more than a litre of oil every 800-1k then there defiantly something wrong!!!a fresh engine should lose no more than half a ltr every 1k...
As for what oil iv always used at least a 15-40 but even better a 10-60 or 20-50
Valvoline racing is the best for a yb in my opinion or millers iv used castrol if i havnt been able to get my favourite...
If you got through 5 ltr in 1k in any period on a fresh engine then believe me its burning way to much oil!!!


cheers danny