having trouble . believe it is electrical. bike starts and runs but after say 15 miles engine management light comes on and display goes off. drop gear and rev it usually comes back on. any ideas. can anyone help. cheers.

Its not quite the same but I had a Toyota van years ago that had the exact same issue and the problem was the oil pressure.

Assuming this was for the 2009 660 in your profile I moved the thread to the relevant forum

Also, iirc, check wiring around the headstock

Further investigations on 660.com suggest maybe loose connections,water in system, low battery........perhaps

Thanks for suggestions. Have already replaced rectifier/regulator, had charging system checked and renewed battery. will try suggestions and see what I can find