Seizing's the big worry obviously, but lubrications also primariliy about lubricating parts to slow down wear.
so, basically, the less oil the more wear.
Correct oil mix percentage 3% ?
2% on a rotary valve vespa (post 1959 except GS and SS) ,and 4% on a lambretta.
Piston ported engines aren't as efficient at lubing the crank as rotary valve where the fuel charge goes straight on to it, ok given a mugello barrel is ally nicasil runs cooler and harder wearing etc and synth oil is supposedly more efficient ,but with harsh modern fuels added to the equation i don't get why people run an engine designed to run on 4% on less
Piston ported engines aren't as efficient at lubing the crank as rotary valve where the fuel charge goes straight on to it, ok given a mugello barrel is ally nicasil runs cooler and harder wearing etc and synth oil is supposedly more efficient ,but with harsh modern fuels added to the equation i don't get why people run an engine designed to run on 4% on less
Forgive my ignorance if I'm mistaken but does adding less oil not make it richer, ie richness/leaness refers to the proportion of petrol that will burn and not the among of oil added.
Yes, adding more oil makes the mixture weaker and I believe petrol can also have a cooling effect.desi wrote:Forgive my ignorance if I'm mistaken but does adding less oil not make it richer, ie richness/leaness refers to the proportion of petrol that will burn and not the among of oil added.
Adding far too much oil can make them run hot /the petrol mix weaker but that's adding far too much, not 4% 
Adding far too little will result in not enough lube = lean running , and although the cold petrol charge coming in is part of the cooling process modern fuel and it's additives such as ethanol don't help towards cooler running .