Does it only do spill out of the breather when the tank is full? Or does it do it regardless of the amount of fuel in the tank?

I see yours is an ABS Ten. They have a completely different tank, much higher with a bulge at the top around the filler cap and a different shape round the front where the battery sits. I am not sure whether the breather exits in the same place as the "normal" bikes, or whether it is in the same position internally? Can you say where it exits, or show a picture?

I suspect maybe the ABS models are more prone to this fuel expansion problem? If they have the same size filler (same part number) neck as the standard bike then, because the higher raised area around the filler, the air space left to accommodate expansion will be much smaller when the tank is filled to the bottom of the neck? Haven't heard anyone with this problem before though...

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