I am hoping some one out there can help me. I just have a bored out 400ex. It is on the first bore of 3 for a 440 kit. Compression is almost 11 to 1 and I am running pump gas. Does any one out there have any suggestions for what grade oil I should run in this thing? I abuse it to know end and I would like it to last as long as possible.

 

honda gn4 10 w 40 is what i use in my z400 . it is good oil...