Hello all , a few weeks ago our Excel twin cam has started losing power .It seems to struggle off the mark then after about 50mtrs it runs fine . It doesn't matter if the motor is hot or cold its the same .I have replaced the plugs cleaned the throttle body had the cam belt changed 500 kays ago and used some injector cleaner to no avail . It doesnt misfire and starts first time . It feels like after 50 metrs it hits the power band and takes off like a rocket ( well as much like a rocket as an Excel can lol) Thanks in advance ,Dave C