2 litre Aircooled loss of oil

[Simon james]

Need some advice
Was driving nicely along yesterday returned home after about 25 kilometres and noticed very large oil leak
Checkout underneath and noticed it wad coming from the lefthand side pushrods . Two of them
Check oil level which was just on min
Fixed the pushrod problem added oil and then started the bus
Didnt sound the same for a minute or two .Sounded like a knock but this quickly stopped Running like a hairy goat now Spark plugs very black oily .
Has twin webers 44 idf
Getting worried i may have stuffed it with the oil leak
Oil warning light never came on so i guess there must have been enough oil
Any thoughts
Thanks Simon