My JD 1984 850 has approximately 900 hrs on it. It starts easy, runs great, seems to have lots of power etc. However, it has a fairly loud knock which is most noticeable at idle. It also smokes a bit -- appears to be white smoke with MAYBE a touch of blue. Every few seconds it appears to puff out more smoke than usual, and I think it also makes a very light bump sound when it puffs the smoke. There is no water in the oil, no gas bubbles in the radiator. It has new injectors. Any ideas on what I should look for? Thanks
Scott
Scott