91 KDX 200 - I have a groove on the intake side and the cylinder is also out of round a little. Is it true that the cylinder cannot be bored or honed. If so what are my options and refrences.

I also found my left exhaust valve broken in three places. Will I notice a difference when replaced and is this pretty common?

Thanks for your time and help - "broke down in Virginia"

The LHS valve usually strips the gear at the top, but all the valves are prone to seizing if you don’t take them apart & clean them every so often. The pay-off is Yes it will make a noticeable difference. More than if you invested money into trick bolt on bits.