Yeah I have used petrol for this purpose before I was just trying to think outside the square

To Grumpy. This weekend I am finishing the striping down of the motor. I intend to soak all the parts in petrol for a day or two and then degrease for final cleaning. As to the breather I think that looks like being a problem due to the amount of crud in that area. All I need to purchase is a 6" gear puller as the flyweel does not want to budge.