Technical Oil in air filter

[dongiannis]

I noticed oil in air filter and connecting tube that leads to carburettor.
What is causing this and how should I fix it? Engine works fine, without power loss and the level of oil is correct.

Thank you for your responses.

 

[bugsymike]

I noticed oil in air filter and connecting tube that leads to carburettor.
What is causing this and how should I fix it? Engine works fine, without power loss and the level of oil is correct.

Thank you for your responses.

Sometimes on worn engines it is possible to feel the crankcase pressure at the oil filler cap with engine ticking over when warm, if excessive it may indicate worn pistons/cylinders.
It may just be a case of cleaning the breather pipes and crankcase breather filter side, so engine cannot build up so much crankcase pressure.