ORIGINAL: dannafinance
This is a statement right of there owers manual.
MAINTENANCE: Your new Brison engine will be, practically, maintenance free for several seasons. We do recommend a crank pin needle bearing replacement every time you have a prop strike or aerial crash. Maintenance of these bearings should be considered every 200 to 300 flying hours. Periodically check the sensor and ignition leads for chaffing.
Yep,it's on their web site.
Here is another "interesting" recommendation regarding fuel & oil:
"FUEL: Use high octane gasoline, leaded or unleaded with a good quality 2 cycle oil. You should use only synthetic oils such as Amsoil or Klotz. The recommended ratios are 64:1 to 100:1 with 64:1 being petroleum based oil and 80/100:1 being the synthetic. Our engines will run at 100:1 with GOOD synthetic oils. Never use more oil than necessary because it will stick the rings, causing the piston to melt, voiding your warranty."
I've run both petroleum based oil & synthetic at 40:1 & at 50:1 in my engines & have never had a "sticking ring."
64:1...? Well,I guess I just don't agree with that & I don't agree with the bearing replacement.