Gents I went 'round and 'round with BD for about a year over oil temp warning light, which after using a thermal sensing dipstick in the reserve tank showed the oil was truly too hot.
This was with a TP 107" motor.
I made a call to, got an invite and visited with the good folks at Total Performance Engineering (an engineer, not a sales guy, one of the guys that designed the TP 107) and he told me they'd been recommending oil coolers on 107+ for a long time. BD simply refused to admit it. He wanted to make sure everything else I had tried was done properly and there were no stoppages or clogs in the system before he told me that.
I did some homework and finally went with twin Davern Machine aircraft grade aluminum coolers, with leather covers... using AN adapters to avoid leakage- but the bike wouldn't warm up fast enough, heheh. I solved that by putting a thermostat on the left hand (only) side. Keep in mind hooking up all that with braided hose helps keep the oil in the wind as well, mine took 8' of braided hose, which I would guess is like adding a third cooler... so it goes like this:
Right hand cooler is always on, with some additional braided hose and a leather cover.
Left hand cooler (and additional braided hose) comes online when/if the oil temp reaches 190 degrees or higher (due to thermostat), and helps let the bike warm up faster than if there was no thermostat.
If the temp continues to get out of hand, I remove one or both of the leather covers- I've only had to do that twice in the last 8 or so years since I've made the change. Both times I believe it was when I was stuck in beach traffic on very hot (100+) days. But I haven't overheated since making the change. More oil moving further, even in stop and go traffic, makes for cooler oil. The system doesn't leak- though I have had to change the thermostat a few times. But hey it's a thermostat, you know... remember you're old Plymouth?
...it does make for a 5 qt oil change, if that's a problem. And this all happened back when we were arguing over synthetic vs fossil oil. Synthetic oil does run cooler but I bet all youse guys is running that by now.
Funny I just tried to do a search for Davern Machine, it looks like they got bought out or are out of business.
The Harley ones is butt-ugly IMO... but there's some others out there that don't look too bad.
My other bikes have 88" motors, but if they were bigger I would run a cooler like I do on the 107. In fact, I would run twins like I do now. LOL, one guy a few weeks ago on an anniversary K9 says: "Ya and I got twin oil coolers". I said to him: "Really? Do you think I'm stoopit or somethin'? One of them is a spiked cooler, the other is a stash tube--- unless like there's an invisible delivery system run from one to the other within the frame. There's no hose between them."
He says: "Well OK, one's a stash tube."
I accepted a beer. I wonder if he really knew before I pointed that out? Oh well. I talked to him about the benefits of a thermostat.
Peace,
OHM