I've been using 89 octane just as a precaution against detonation. I haven't experienced any yet. I don't notice any particularly excessive heat coming off the engine, but it's been pretty cool here lately. Before installing my oil cooler I did notice the clutch freeplay increased after a few miles on a pretty steep grade running the bike close to maxed out. I've since run that same grade under similar conditions and didn't notice much change in the clutch freeplay at all. I've got to assume that if the oil's running cooler, it's helping to cool the engine as well. Particularly because the cooled oil returns back to the valve cover and sprays down onto the rockers and the top of the head with the cooler setup I'm using, I'd think it would help with the temperature of the top end as well. I'm not going to go to any great lengths to quantify the relationship between oil temp and cylinder head temp though. My seat of the pants impression is that the cooler does help significantly.

I have all the stuff to install an oil cooler on mine, but just haven't done it. I don't want to mount it low, so I will probably make a bracket, if, I ever do use it. I don't get into the real slow speed hash terrain, and most of the towns that I go to, are what many would consider a fairly small city, so it's not very often that traffic would be a huge issue., but I still may do the cooler one day.

Yeah, I didn't want to mount mine low, or where it would be blocked by the fender, so I made up a customized mounting bracket from the bracket that came on the cooler in my kit. I don't have much occasion to idle in traffic, for one, because there's not a ton of traffic in my area, and also because lane splitting is legal here so I can (safely) go between cars to get to the front at a traffic light. Like I'd mentioned, prior to installing the cooler, the only time I'd noticed the oil getting excessively warm was by way of the clutch feel and that was immediately after having just run the bike pretty hard for a few miles at freeway speed, so airflow across the engine wasn't an issue in that case. I figure I'll encounter high oil temps on slow, technical single-track trails where I'll likely be using the clutch a lot. If I notice the clutch feel issue under those circumstances then I may look into installing a fan for the cooler. I'll hold off until I see if it's actually an issue though.