Originally Posted by Nilks

Haven't really experienced any engine that was "hard" to tune (besides engines with ceramic front bearing - that can be quite a pain to tune), but in my experience the OS engines are better at holding a tune.

In my team we run 2 different brands of engines: Ninja JX and SH engines. Ninja JX as the "top engine" and SH as the cheap alternative. I run the Ninja engine (which is an OS), and I pit (and tune) a SH. While they both a pretty easy to tune (if you know what you are doing), the Ninja JX holds that tune the entire day - while the SH needs to be re-tuned a couple of times a day.