the easiest way to adjust your sled is through the clickers. I run a 2002 Summit X 800 and, depending on the time of year due to the ambient temperature changing, I will have to adjust my clickers to allow my sled to run at 8000 rpm. This rpm is not only safe but it is the rpm when your sled will perform best. You can also make spring change in your primary. There are two numbers that dictate a primary spring; the first will effect the rpm at which your sled engages, lower numbers means your sled will engage sooner, the second number is your finish. This number effects the rpm at which your sled will perform at w.o.t. Again, lower numbers will drop your rpms. If you do a spring change, dont adjust your clickers until after you have run the sled once. Once you run the sled, adjust the clickers as needed, each clicker number is worth roughly 200 rpm. Also, the best place to check your w.o.t. rpm is in the powder since your rpms will tend to be slightly higher on the hardpack. Hope this helps