Hmm?
The ecu is made by mitsubishi iirc?
..possibly you have a full power ecu and the previous owner has installed an aftermarket restriction kit....(cheaper than a new ecu)
Quick check..lift rider seat....lift out ecu which sits behind battery.... check the part number( MT something something something)...if it ends in 60 its full power, and if it ends in 61 its restricted.
If its 61 then you need a replacement one for yer 70bhp or so....i got one second hand a month or so ago from england through a breakers i had to almost stalk over the phone
.... they can be quite difficult to come by second hand for anything like reasonable money.
Drop me a pm if you need one and i'll see what I can do.
If its full power already and restricted through an aftermarket kit then im not sure...as you stated-possibly throttle stops and/or inlet washers...
Throttle.... open up throttle assy...2 screws iirc....check for anything that looks like its stopping full throttle movement.
Inlet washers,
lift tank, lift airbox....look for washers there...if none then lift throttle bodies....if no washers there then its not restricted.
Strictly speaking on the FI models there shouldnt be inlet washers for restriction....theres two sets of butterfly valves afaik..one controlled by the throttle, and the second controlled by the ecu in response to your throttle input and all the measured thingies that the ecu takes care of...so it would be "self restricting" if the throttle is limited.
..best thing to do is get in touch with previous owner and ask what he had installed if anything.....he may have bought the kit just for the cert or whatever to show to insurance to get insured.