You need to validate your gauge, somethings not right.
"From what I've read, dino oil starts to break down around 250 whereas synthetic oil starts to break down at 300."
Good rule of thumb, I would just add that no you don't necessarily need to pull over and change your oil if it breeches 250, just understand that for about every 10 degrees you exceed the max threshold, your oil life gets cut in half. So when you hit 260 your oil is good for 2500 miles instead of 5000, 270 your good for 1250 miles. This is one of the big reasons a lot of folks run synthetic oil to raise the temperature tolerance threshold to 300, so you really don't have to concern yourself with it getting too hot.

 

I would say that 190° was normal operating temperature for cooler ambient temperatures, and for me that would be ideal at any time. I would be happy to run 190° in summer, but that won't happen in S. LA. Your lower readings sound low unless you are running in cold AT's. To test your OTG accuracy, heat the oil up and measure with an infrared thermometer and/or meat thermometer. If you do it while draining for an oil change, be advised that the oil will cool very rapidly once it hits the drain pan. My OT runs close to an infrared reading of the bike's oil pan, so that may be a good measuring method, too. Be advised that the accuracy of these OTG's may vary, as has been discussed here in other threads.

Like Wldbill and Sancho said, since our bikes are air-cooled OT depends greatly on AT. My SG with an oil cooler rarely runs above 180° when AT is below about 60°, and lately in 80-85° AT it has stayed around 195-205° depending on how fast I'm moving--the lower end of that range for highway and upper end around town. In summer (90°+) it runs around 205° as long as I'm moving. Peak is 230° over the past five years but only rarely in slow-moving summer traffic, and it hit 240° OT and 330° ET (front head) once last year in one particularly bad traffic jam on the interstate. In that case I was about to pull over for a cool-down and flash to a richer tune when the traffic started moving again. When OT hits 230° and ET 300° I start thinking about extra measures like this, as that's about the limit for me.

I've checked my OTG and it is within a few degrees of true. A friend has an 2010 SG with no cooler and his OT stays about with mine in cooler AT's, although we've never checked his gauge's accuracy. Another friend with an '09 Ultra with cooler and Stage II (103" with 255 cams and a lean economy tune) runs a bit higher than me, but stays in sane territory so far after <1 year of watching OT's.

I would do some accuracy checks on your OTG and see if the OT's rise during the summer months. Where do you live?

 

My HD gauge indicates 230 when the heat management kicks in and shuts down the rear cylinder. I can't remember exactly when this is supposed to happen, but its something like 285. So I believe there is a temperature lag between the location of the sensor and the actual temperature that the computer is reading to engage the heat management system. In another words the oil temperature is highr than the gauge indicates. IMO!

 

Been doing a little research on my 09 and it's reading simular to what some have said. Running synthetic oil, oil cooler and thermostate, stage I, true duals. Checked the oil temp sensor for accuracy and it's within a few degrees. Also have the digital dipstick and JES analog dipstick and both will read within about 3* of each other and show accurate in boiling water.

Doing mainly normal highway crusing: On 50*-70* days I run about 185*. On 75*-85* temp range is about 195*-205*. On 90*-95* temp range is 215*-225* Humidity always crappy if above 80*.

Started out with the HD oil temp guage and switched out for the Medallion guage set. I like the oil temp sending unit a bit better with the medallion. Sticks out further in the oil pan for a bit more responsive reading IMO.

HD oil temp guage inside pan adapter:


Medallion sensor on Left and HD sensor on right. Notice Medallion probe will be in flow of oil. HD sensor hidden inside adapter:


BTW: Others manufacturers have simular type sending units.

 

I lost a 103 engine at 5000 miles...last Oct. Just before I carried it to the dealer, the Amsoil Sync 20-50 oil was like it came out of a diesel...black as ****. It had some heat on it. I felt a lot of heat, but the dealers said it was normal. I could feel it burning my leg through the chaps so much that I would put them on the highway pegs for relief. Never idled it, I do not normally ride in traffic. Never did hear what happend to that engine.
After the new engine was installed, I installed an oil temp gauge so I could watch the new engine. The bike is stock except for the CAT which has been removed from teh header. The 2012 103 has a stock oil cooler. If the outside temp is above 70, then I see 230 regularly. I have seen 254'F running 85mph on the interstate for extended periods fully loaded this spring already. I am wondering what kinda temps I will see this summer in 100'F heat.
One thing is for sure...these Vtwins run hot...

Kinda scary...what what will I do if I see high oil temps? Not sure, since it is still under warranty...I might just press on for now...

 

I have an oil temp gauge in the dipstick and an oil temp sensor that is put in the front of the oil pan (by the oil drain plug). There is about a 20 deg F difference between these two, which is normal and can be explained. It is due to the "serpentine" designed oil pan HD has. The hot oil returns in the back (towards the oil dipstick). By design, the serpentine oil pan should (which is why it is designed this way) cool the oil by the time it reaches the front of the oil pan.

Now, with that said, if the oil doesn't get above 130 and barely 180 (unless it is very cold outside) is highly unusual and you should check you gauge.

 

just ride. if it catches fire or siezes up , then check it out.

 

Have the Harley temp/dip stick. Sometime I check temp after shutdown and depending on ambient temp and distance traveled, the temp will be between 214 and 244 degs. The Harley engine is made for wide temp range. I don't worry about oil temp.

 

EITMS works with ET (engine temperature measured by the ECM at the front head), and that can be lower or higher than oil temperature, often by a considerable margin. I've seen differences of 100° or more, as head temp fluctuates much faster, so you can't judge EITMS events by oil temperature.

 

Your gauge is defective...