kwik129

I own a 1978 Yamaha ET340B sled and am a complete novice. Figuring things out as I go and having fun doing it.
The person who I purchased the sled from said there may be something wrong with the oil pump? He was not using the pump to lubricate the engine, he was pre mixing and it smoked bad. His pre mix was 50:1. So that oil pump was working dry which probably trashed it?
I took the top end apart and found the cylinder wall slightly scratched but the sides of the pistons near the wrist pins were discolored. Going to bore .010 over and put new pistons in.
That brings me back to the oil pump. I can pick one up for $60 but funds are tight. Is there any reason why I could not pre mix for now? If so, what ratio?

Thanks.