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2019 road king special thinderheader and air filter with tuner. Ok so Ive been looking forever and can’t seem to find any real info on what the actual running engine temp for the m8 motors are. They say 230-260. I have always had the oil temp dipstick but that is a different temp than engine temp. I never worried as it never hit 200. After getting a pv2 runner and deciding to leave it on the bike for more gauges on my road king I have noticed standard running down the road temps to be 270. If it’s hot out or I am sitting in traffic on a 70-80 day I can see it go as high as 315. Bike doesn’t seem to be any hotter than it ever ran before. At what point is the temperature an actual concern. So many people say oh my bike runs cool at 210 but are going off oil temp not engine temp. Being unless you run a runner that gives you an actual engine temp reading most have no clue what the bike runs at.
Hey Bro, been having the same problems with my 2017 Road King Special Oil and Air cooled and I can give you some idea's what i have done to cool the cylinder head down (The front right is my problem) and my oil. and I got the same questions and answers as you do regarding high temps and i have done a lot of stuff that has changed my temps. I've contacted Vance and Hines about the maps I have flashed from the FP3 and they don't know **** about temps, but their so called service techs keep giving me maps that make my engine run hot with maps that have the air/fuel ratio all wrong causing the front O2 sensor to act funky and give high temp readings .and I just figured that out. First the standard stuff a Arlean Ness Naked Air Sucker that I added a External Air Breather Kit , I put on a dip stick with a breather mod to help relieve Crank case pressure, I didn't see much difference in oil temps. I have read about Trask Crankcase vent mod and it could be helpful, but a little overpriced in my opinion. I replaced the oil pump for Harleys upgraded oil pump for the earlier M8's and got cornholed on the labor charges., but it put to ease concerns I had on a common problem of Oil Sumping on these bikes. Next I added Harleys Oil cooler fan assist, as these bikes don't have a stock fan for the oil cooler and the fan was another trip down to Harley to get cornholed again to have them flash the fan to the ECU. I was not happy with oil temps and Cylinder heads at this point. I even melted all the gaskets on my new Air Sucker so I purchased a Ultra Cool Oil Cooler with Dual Fans and a Ultra Cool Lifetime oil filter and finally I see results and oil temps are running nice and cool, but heads are still up in the 350-450 on front of cylinder and the Ultra Cool doesn't coexist with added fan on the stock oil cooler so I run the Ultra Cool cooler and Dual fans with a test plug and wire a toggle switch so I can run it with the stock cooler and oil is running around 240-260. I put on one inch tank risers two and three inch risers were too much and looked goofy. One inch looks good and brought cylinder head temp down about 40-50 degrees. Cylinder head can still get to 450 easily ,but the temp seems to be the hottest at the first bend in Vance and Hines Dual Dressers Front pipe not the cylinder giving pipes external heat felt on legs. I can live with that. I did remove the cat from header pipes and baffles from slip on's. I only solved half the problem of the cylinder heat with all this bullshit and will probably go to Harley and get cornholed again for some head work as I search for the perfect cylinder head temps.
So either everybody's bike is broken, or none are. Sincere question - are the bikes owned by the 99.99% of bikers who don't measure head temps blowing up?
Heat has killed 3 crank sensors within 400 miles (last one melted). After the 3rd the motor was torn down all the way to the crank. Oil pump seal was blown, no other visual problems. Tune has now been modified, and adding Ultra Cool parts as we speak (oil cooler, filter, and HD oil cooler fan). Fingers crossed for the best. 129" 11.25 motor.
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