RX3: Engine Top End Rebuild at 22,450 Miles

[SpudRider]

Since I received my RX3 motorcycle, the valve clearances of my NC250 engine refused to stabilize. Therefore, I needed to adjust the valve clearances every 2,500 miles. After riding the motorcycle about 16,000 miles, the exhaust valves finally stabilized, but the intake valves did not. With about 22,450 miles on the odometer, I reached a point where the intake valves were completely tight only 1,000 miles after the last valve adjustment.

At this point I strongly suspected my intake valves were receding into the valve seats. Last fall, after performing a leak test, I got authorization from Gerry at CSC to take apart my engine. With the engine apart, I discovered major recession of the intake valves.



I repaired my engine this winter, under warranty coverage. My engine has been running well for 3,000 miles since the repair. Several days ago I checked the valve clearances, and they had not tightened since the repair, so I am pleased with the results. This thread will document the top end rebuild of the NC250 engine in my Zongshen RX3 motorcycle.

Here is a photograph of my repaired RX3 motorcycle, taken several days ago, just before I checked the valve clearances.