What's the right engine temp for a fully warmed up 4-stroke 150cc? And where do you measure it? What about oil temp? I got these gauges in the mail... In fact the big digital one was cancelled but the china seller sent it anyway. I don't know which one is right!! The big digital one has a 6mm probe while the other has a 3.5mm I think. I bought a gauge so that I knew when the engine was warmed up before I started riding... So how warm is warm enough?