Stripping down an engine and cleaning out all the residual oil with brake cleaner after every meeting isn't good for the life span of an engine, unless you're prepared to run the engine rich for a tank before each race to oil it up properly again.

I check for play on the bearings and replace as required, change rod at frequent intervals, this is all the maintenance you need.

If your fuel is rotting the bearings then you're running poor fuel, switch to Meccamo or Runner Time, yes it's expensive but your engines will last much longer.