Modern Vespa

I want to add a 5 gallon tank to my Piaggio BV200 for an upcoming event. I am looking at a 5 gal plastic fuel cell. I have removed the evap canister and have a vent tube that I can use to gravity feed the stock tank. My questions are about the venting of the added fuel cell. Is there something I can mount on the cell itself? What about the fittings? They are talking 6AN, 8AN, terms I am not familiar with.

Something like this:

http://www.amazon.com/Jaz-Products-250-005-01-Drag-5-Gallon/dp/B002RLCLXE

I plan on replacing the trunk with the tank for the ride. Will I have any problems with law enforcement over the tank?

I have a 3 gal. aux tank on my 300. With the evap system gone, you are correct in using that for a gravity feed. My aux tank has a second fitting on top that is used for the vent. I got my tank from summit racing, so it has the tip over valve. I simply fill the main tank to the level of the previous evap line , close the cap tightly, and then fill the aux tank. This has work very well.

I should have added that I have the tank for 3 yrs , and no problems with law enforcement. I would make sure that you have an approved racing tank for legal reasons.

Ordered the tank from Summit yesterday. Now I need the vent for the top, a plug for one of the feeds and a fitting to connect to the stock tank vent. I will have 8 gallons of capacity, that should allow me to circle Lake Tahoe non-stop.

Good luck should work well. Thought about this event, but can't get away.