Hi folks I have done a big rebuild on my Xr6 and since then had problems with it overheating. There seems to be too little oil reaching the head, (lots of bubbles and fumes not much oil) and I have burnt out a set rockers. I have checked all oilways and seals thoughly, everthing is clear and clean. Tried new oil pump and yes I did remember the little dowls and o rings behind and the in front the oil pump, no better. Any ideas I tried everything I can think of? One suspect, I checked the crank shaft and it seems that is has almost no back pressure. I can imagine that the hot oil might choose to go this way rather than up hill to the head. Sound plausible? Should there be some resistance? Is there something in the crankshaft that restricts the oil flow or is it just the size of the oil hole in the carnk pin. I had a new crank pin and con fitted is it possible that the workshop could have fitted the wrong pin. I can tear down the crank, but its a big job. Can anyone tell me how big the hole in the crank pin should be so I can check it once it's out. Any help much appreciated I am at the end of my teather.