Because of the turbo in the JD. We have seen tons of burned up JDs. And the dollars involved. I have seen combines glow when combining sunflowers. Poof and they are history. Actually we are JD people and they have good equipment, But we are really not impressed with our 9650. The 860 does a better job. Hands down. There is a reason they call JDs the long green line. May do a better job in corn but not in wheat or barley. The guys are really impressed with the new Massey Combines. Cats are nice too. Was not impressed with all the hydraulic lines on the Internationals.. Open up the side of these new combines and take a peek. It'll scare Ya. Also there is a bunch of grease jirks( on the JD,) takes alot of time. Cleaning out the auger is a bitch. Dreadful. Simply what works for some doesn't for others.