Im looking for a engine to put on my homemade kayak. Its about the size of a regular smaller kayak, 200 cm in length and 75 cm in width.
This jetkayak has a topspeed of 40km/h and that would definetly be good enough for me. HS-006J6C-Product The main technical characteristics,Jet-Ski, amphibious motor boats, power surfboard - Jiujiang Poseidon

I have an old 125 cc susuzki gp motorcykle engine but dont know if i can use that. I guess i would have to change gear in some way for it to have some speed on water? it goes 110 km/h on land.

Any sugestion of a good and not so expensive engine? Was thinking to buy some old 1000 dollar jet ski and take the engine from it but i think most of them are to big and heavy for my needs.