I’ve got a little 65cc 2 stroke when is best to put coolant in it. I’ve only got distilled water in it at the moment and when I put it in do I only fill it up with coolant or 50/50 mix coolant and water
I wouldn't run my bike with water in. Always use the recommended coolant in the user manual. These can be found online if you don't have one. The coolant I buy you just pour it straight in. No mixing required.
The distilled water is to flush the system out. This removes all of the old coolant. Also if you buy concentrated coolant you will need to dilute it with distilled water. Hopes this helps.
You can but it is not advised. Check your manual and see what it says, probably something along the line of a 50/50 mix of coolant and distilled water.