im stripping out my tank ,at weekend i drilled a hole in the top of tank put a small peice of pipe in it and run a length of hose as the breather to stop the tank walls being sucked in.

what has everyone eles used ,should i leave it open to noral air,or put some time of one way valve in it .
thanks
simon

Just use a long piece of hose and bend it in a loop at the top so its pointing downwards somewhere near the bottom of the tank. Personally I would leave it vented to atmosphere but others prefer to put a valve in the end. Choice is yours really

Try and get a motorbike tank vent valve, couple of quid, then means no chance of spillage. I was surprised how much the fuel is "pushed" to the end of the tank in fast corners. If you have a full tank there is a chance of fuel spilling, happened to me at Brands on a trackday.

MSA regs call for a one way valve for competition, just bung a servo valve on the end of the tube, zero cost as you will not be using the servo from your donor.

Regards Mark