UPDATE:
What. A. Mess.
A close family friend had bought a 2015 ZForce 800 in Black from us shortly after I took him for a ride in our unit. At 720 miles, he had a hard time starting it, and when it did run, it couldn't get out of its shadow. Brought it in, and he too had dropped the rear cylinder. 60psi of compression in the rear, 150psi in the front. Air box was full of blow by, but his intake was spotless. With his, we have NO idea why his went down. His rear connecting rod had gone as well. CFMoto sent us a motor for his.
CFMoto was insistant we rebuild the top end on our which we did. How ever, we got less than 2 miles down the road when we lost power and had a bad clank from the motor. Just as we had warned CFMoto would happen, the rear connecting rod bearing took a shite, which wasted a BUNCH of time doing a top end rebuild. They sent a replacement motor for ours that day.
Now here comes the fun.
They don't have any Z8 engines in stock, only the X8 engines. I was told the only difference was the intake, and the side fan. Well, theres a LOT more different. The oil lines are different, and the oil temp sensor is in a location where one of the hard oil lines is, which means you can't just the oil lines over. The hole for the temp sensor is smaller, which means the X8 engine uses a different casting all together. The X8 also has a stator that uses a much shorter pigtail, so we ended up having to swap the entire left side crankcase cover. As far as the oil lines go, we just have to extend the oil hose going to the back side of the motor to make up for the hard line that was facing the rear of the unit.
After ALL that work and getting the motor back in, we fire it up. Oil pressure sensor light is flashing. minutes later, still flashing, and the temp is rising quickly. We shut the unit off, make sure there's no air build up in the coolant system. All is right there. Thinking maybe its the sending unit, we replace the one that came with the engine with the one off the old one. Fire it up, still flashing, temp runs right back up. We shout it down, and remove the from cylinder valve cover, fire it back up, and no oil is making its way up to the head. Take out the sensor, put our pressure gauge on, and fire it up again. NOTHING. Brand new motor… NO OIL PRESSURE.
I had to tear that motor out, break it back down, take the 2nd motor which was meant for our unit, tear that one down, convert it over, and put it in the customers unit. That one built up pressure just fine.
CFMoto told me it was most likely the oil pressure regulator which was behind the clutch housing on the left side, so I tore that motor down, check the pressure regulator, and its fine. So, we STILL don't know why the 1st NEW ENGINE has no oil pressure, and I still have my unit, and month later, with no engine.