Genuine Aprilia fuel hose AP8144226 (ex AP8120990)
This is the main fuel line that is located on the fuel pump assembly inside the gas tank.
Part position highlighted in red in the diagram below.
***Please note: The Aprilia parts catalog incorrectly specs hose clamp AP8102765 or 890435 for use with this hose. THEY DO NOT FIT. The correct clamp for this hose is MC53175K23, sold separately; two are required.