Wr450 started to blow smoke under high revs but started ok and had stacks of power. I decided to get it checked out as I did not want to cause any further problems. Well it ended up the cylinder was scored. Cylinder,piston, rings, and valves were replaced by a motorbike engineering place. First ride was a four day ride in the desert.I lasted 65klms and then the bike would not start. I took it back and was advised the timing chain skipped a sprocket and timing chain and tensioner needed to be replaced. I said ok. Next ride out the bike lasted 28klms and then would not start.It took 4 hours to get the bike out. Fuel is ok, Has spark. Bike will back fire when you kick it but will not start. I have so far spent A$2500 having the bike repaired. Feeling pissed at this point. Any Ideas?