dpr9z? dpr8z? plugs

[honda400ex1999]

what plug is better to run on 9z or 8z .

what mods and where do you live? I just switched to a 9 but i havent had a chance to see how it runs yet. Its good for high compression, advanced timing, over bores, high speed riding, and hot weather. If you have any of those I would say switch

[Wheelie]

IMO--Internally stock motor, cam being an exception--8z

High compression, big bores, etc--go with 9z

[honda400ex1999]

i live in south texas and do not have many mods on the motor except white bros e series full exhaust , 155 main 38 slow , amr rev box stage 2