Firstly it's good to see some motorcycles being depicted on Australia Post's 'Road Trip series of stamps. Even if the riders appear to be a pair of pratts who leave helmets and gloves on while having lunch. But the question is, what's the bike in the foreground? It's an old one. There's too much detail to be a generic artist's impression of a bike and all the other stamps in the set have specific vehicles and the yellow bike on the background is obviously a HD soft tail (possibly a Fatboy). There's what appears to be a decompression lever on the right handlebar of the red bike and it seems to be a V twin. Any suggestions?