Bearing life depends on the type of fuel/oil used. I've always used 30% nitro and 10% oil, whether it was mixing my own or pre mixed. I used to get around 150 flights when I was using Cool Power MV. Cage wear was the main problem. Since switching to Rapicon, bearing life has increased significantly. On my current 200cdi, my last previous rebuild had 340 flights before I stripped it down. Bearings were a little rough, but still OK. I'm up to 158 flights now and will probably got to 400 flights, then rebuild it.

During a rebuild, naturally I replace all O rings and gaskets (including the head gasket), bearings and oil seal. I measure the ring and only replace it if it's too worn compared to a new one. I inspect the fuel pump and back plate assembly. The fuel pumps have been super reliable the last few of years, with no need to replace it. As long as the rotary disc has slight resistance when turned, I don't adjust or pull that apart.

Ignition modules were very problematic in the early 170/175 days. Since the version 2 cdi module came out, I've had very few problems and haven't had to replace for around 5 years. My Xareltoo is 4 years old and still using the original ignition module.

The back plate also was causing many problems, with the main issue being the sensor wire breaking. Once I sorted that out, I haven't had to replace a back plate for years either. Both my 200's are still using the original back plate, with over 722 flights on one of them.

I check tappet clearance regularly and set to a tight 0.0015" when cold at TDC.