Do or don't?

[Nessism]

Coincidentally, the same time the engines with reduced cooling fins came out.

This is true but not the full reason.

Sump temperatures over 250F are bad, and nothing we should wish on ourselves. Our beloved GS engines are fortunately tough as nails though and seem to live though this abuse, although I expect there is incremental wear occurring in the engine. Synthetic oil is a good hedge since it doesn't thin as much at extreme temperatures, but I'd go with an oil cooler if living in a hot climate area.

[posplayr]

This is true but not the full reason.

Sump temperatures over 250F are bad, and nothing we should wish on ourselves. Our beloved GS engines are fortunately tough as nails though and seem to live though this abuse, although I expect there is incremental wear occurring in the engine. Synthetic oil is a good hedge since it doesn't thin as much at extreme temperatures, but I'd go with an oil cooler if living in a hot climate area.

I'm now running at about 220DegF indicted and like it there.

[Dogma]

I was uncomfortable watching my oil temp gauge reading 280-290F. I installed a cooler and got an immediate drop to 210-220F, so I think it was worthwhile.

My thinking is that the key to the whole thing is the oil temperature gauge telling you what you need to know. An oil cooler seems like a lot of fuss if you don't even know you need it.

[tkent02]

My thinking is that the key to the whole thing is the oil temperature gauge telling you what you need to know. An oil cooler seems like a lot of fuss if you don't even know you need it.

Exactly. If these engines wore out quicker in hot climates, maybe a cooler would be a good idea. They don't. Usually they run forever until someone messes with something they shouldn't have....

[Mysuzyq]

My thinking is that the key to the whole thing is the oil temperature gauge telling you what you need to know. An oil cooler seems like a lot of fuss if you don't even know you need it.

Some of the research suggests that oil life is effectively halved (at least for conventional oil), for every 10C over ideal operating temps (a little over 100C-212F), so it would be worth it IMHO, to add a cooler if the temps warrant it. The OP likely does not need to bother with one, at the local ambient temps he mentioned, but at elevated temps like Roger posted about, it does make sense.....cooler oil will benefit the stator too, in terms of longevity. At least on the 1100Es, adding the cooler isn't much of a hassle, given the provisions from the factory.
The downside is that riding during fall/winter, it might be difficult to get to ideal operating temps with a cooler, absent a thermostat, block off plate of some kind, or reverting back to the 1100 filter cover, to effectively bypass the cooler.

[isleoman]

Coincidentally, the same time the engines with reduced cooling fins came out.

I thought 1150s came with coolers? I thought I've seen a lot of stock 1150 coolers for sale.

Are the fins on 1150s smaller than 1100s? They kinda look the same to me, but I've never measured them.

[blowerbike]

1150 is the only and the last of the roller bearing engines to use a cooler from the factory.(to my knowledge)