I had the same problem on and after replacing many parts it turned out to be the Crank Position Sensor. It is a different engine to yours but when I went to the agent of the engine to order the part he asked me for Euros200 but I bought the same part by the same manufacturer for euros40. Very often these sensors are used on different cars so it might be worth checking that. If I am not mistaken I think there is a thread with a list of parts on Talkmorgan where you can find the same replacement part and the car it is used on. I spent a lot of time and money to fix the fault but at least I now know my trike much better. Phase sensor faults could be intermittent and could prove very dangerous on the road
