I am in the process of refilling the cooling sytem of my Derbi GP1, but hit a snag.
After a litre or so of liquid it is not taking more. While I found no source about the capacity of the GP1's cooling system, the mechanically similar Vespa is supposed to be around 2 litres. This suggests that air is trapped in the system.
What is best practice to get around this? Brief running of the engine did not make a difference, and I am wary of overheating it.