Join Date: Aug 2011
Location: southern Arizona, USA
Thanked 408 Times in 317 Posts
If you have the shop manual, look at the fuel/fuel tank chapter and note that the tank has an extrusion for the attachment of an air line. This is normally near the top of the tank, the hose is "hidden" under the tank, so that it is out of sight.
Dirt bikes do/did not have as stringent antipollution rules. Honda street bikes from the 80's had vented fuel caps which were functionally the equivalent of the dirt-bike fuel caps with a vent hose.
John: '09CRF230L (Li'l Red Piglet), '89NX250 (sold)
Propelled by Penguin Power
Nekkid motorcycles feel faster
1st bike: a gently used 1958 Matchless 250 thumper