Just picked up my bike from the mechanic after getting the coolant and brake fluids replaced. The bike started fine and I rode off then about 3kms later I'm slowing down in traffic when the bike dies on me. It still has power and turns over but the revs get to about 500rpm then it dies. If I start it and rev it up it goes but if I let the revs fall below 1500 is dies on me again. I had a play with adjusting the idle but it makes no difference. Any suggestions?