hello, as Doc says you need to remove the slinger and replace with a shim the same thickness, also think you may need to drill a hole in the crankcase down to the left side main bearing . i have an RL250 suzuki which runs on premix and has this modification done {the RL engine is based on a TS250 engine which has an oil pump} the right hand main bearing is lubricated by gearbox oil so is okay - as long as you keep the gearbox topped up !