Bit of sideways play?

[billwarwick]

Now, I have no clue of what goes on inside the motor casing and the thought of actually opening it up fills me with dread. Lately, when pedalling, I have been getting a ‘tinkly’ kind of noise on the chainring side. Easy I thought, as I discovered some play in the pedal. New pedals fitted, but no better. On closer inspection, there is a bit of sideways play when the chainring is moved from side to side, maybe a couple of mm. Is this the cause? What is wearing out? Is it an easy fix? Motor is Yamaha and has been trouble free for 3 years.