Ok so now I am more confused.! I spoke to a Yamaha dealer and he said I should run it at 50:1 which means to me unless I am completely wrong, i need to add 200ml of oil to 10litres of fuel......I had been running at 100:1 meaning 100ml of oil to 10 litres This doesn't make sense to me as as mentioned above, the old plugs we covered in oil and excess or unburnt oil could be seen around the spark plug housing once i removed them, and the motor was a tad smokey and running rough at idle........I was under the impression i was mixing to much oil causing this and by adding more oil, would make the situation worse....am i completely missing something hear or could the oil/fuel mix not burning correctly due to the stuffed plugs to begin with.....?