okay, so i have an 04 yz125 and i dont know what i need for oil/gas mixture wise. my bike has a compression of 14.8 to one, because of the new athena top end kit i just installed. also another question would the stock jetting be alright or would i need to change that?
That high of compression, you might need to run 100+ octane. I would also do the 32/36:1 on the premix ratio, but I would bet that your going to need to step up the main jet a size or 2. Best way to be sure, is to run it, and do a plug check.