argus a5 rear bearing
 

hello my engine is argus a5 it has only 5 litres or 1.5 gallon if you prefer this inludes the break in.but only 1 litre is on track all the rest was used in break in.i open the engine to clean it and the rear bearing is bad too loose .if i grap the flywhell i can move it right and left .the engine work great no flame out no overheating.i use hot fire (kyosho) 25% nitro fuel.my lhs told me the reason is the fuel so i order new bearing and a 25% meccafuel.what do you think about this failure of the rear bearing??