go to any bike shop... just messure how long it is. they wil have one that fits nockin about. if not "nah you need a part number m8" try a DECENT bike shop, you know, where the staff dont use a computer to find bits, they just KNOW what they are... or a piggy dealer.
struggle to find such places now. if it dosnt say it'll fit then it wont apparantly. hate all these computerized shit systems. next they will have spark plugs packaged up with part numbers or the individual bike. next time you go into a bike shop after a part, get the registration off their van or something and give them that and see if they come back with the right part.