its a real mikuni from 2001 yz 80, used
i bought a extra cylinder and head to try porting, piston and head mods
I guess there is alot of power to be gained
http://yamaha-enduros.com/index.php/other-manuals?task=document.viewdoc&id=47
check this out if you havent yet
the mx175 stuff should work on our bikes