Engine Temp
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Joined: Dec 2020
Posts: 87
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From: East Memphis
Engine Temp
Curious what is a "normal" engine temp range at idle after the motor has been warmed up (not riden). RG has not been started in about over a month, about 5 minutes after start up I hear the engine fan kick on. Checked the engine temp and it was back and forth from 185-192, I would think these temps would be caused from a hard ride but not at idle. Is this something I should be concerned about?
Seasoned HDF Member
Joined: Jan 2008
Posts: 13,590
Likes: 11,285
From: State of Confusion
Curious what is a "normal" engine temp range at idle after the motor has been warmed up (not riden). RG has not been started in about over a month, about 5 minutes after start up I hear the engine fan kick on. Checked the engine temp and it was back and forth from 185-192, I would think these temps would be caused from a hard ride but not at idle. Is this something I should be concerned about?
Road Warrior
Joined: Jan 2022
Posts: 1,974
Likes: 5,477
From: Woodlands, MB, Canada
It's normal.. The engine is air and liquid cooled. So you're going to see a bit of extra heat when there's no air movement over the cylinder cooling fins.
Here's a post regarding another forum member's experience.. https://www.hdforums.com/forum/2024-...gine-temp.html
Here's a post regarding another forum member's experience.. https://www.hdforums.com/forum/2024-...gine-temp.html
Seasoned HDF Member
Joined: May 2012
Posts: 32,934
Likes: 36,027
From: Carlsbad, CA
Depends where you are measuring the temperature. You need at least 212 oil temp to cook off moisture. Some will say nominal oil temp is 235. I’ve run mine at high speed (90 mph ish) in 114 degree desert heat for several hours. I was roasted, and the glue holding together my plastic Ciro water holder melted, but the bike ran fine..,and did for many thousands of miles later.
Air cooled motors are not like thermostatically regulated water cooled engines, and as such their operating temperature varies. Also, as a reminder your bike has a wet head. It is designed to cool just the area around the exhaust valves to reduce heat to the rider…it has very little impact on operating temperature.
Air cooled motors are not like thermostatically regulated water cooled engines, and as such their operating temperature varies. Also, as a reminder your bike has a wet head. It is designed to cool just the area around the exhaust valves to reduce heat to the rider…it has very little impact on operating temperature.
Last edited by TriGeezer; Nov 28, 2024 at 02:36 PM.
Seasoned HDF Member
Joined: Jan 2008
Posts: 13,590
Likes: 11,285
From: State of Confusion
Depends where you are measuring the temperature. You need at least 212 oil temp to cook off moisture. Some will say nominal oil temp is 235. Ive run mine at high speed (90 mph ish) in 114 degree desert heat for several hours. I was roasted, and the glue holding together my plastic Ciro water holder melted, but the bike ran fine..,and did for many thousands of miles later.
Air cooled motors are not like thermostatically regulated water cooled engines, and as such their operating temperature varies. Also, as a reminder your bike has a wet head. It is designed to cool just the area around the exhaust valves to reduce heat to the rider it has very little impact on operating temperature.
Air cooled motors are not like thermostatically regulated water cooled engines, and as such their operating temperature varies. Also, as a reminder your bike has a wet head. It is designed to cool just the area around the exhaust valves to reduce heat to the rider it has very little impact on operating temperature.
"A Milwaukee 8 engine utilizes oil cooling to reduce engine temperature by circulating engine oil around critical components like the pistons and cylinder walls, effectively absorbing heat and transferring it to the engine's oil cooler, thereby lowering the overall operating temperature of the engine."
"Improved efficiency:
By effectively managing engine temperature, oil cooling enhances engine performance, longevity, and reduces the risk of engine damage from excessive heat. To deal with the heat issue, Harley reduced the exhaust gas temperature by 100°F (55.6 C) by introducing a better water cooling solution."
Road Captain
Joined: Jun 2010
Posts: 528
Likes: 44
From: Jakarta - Indonesia
Have 0 worry. Yesterday I got stuck in traffic for 2 hrs, midday tropical country 100F+. Barely felt anything on engine side, primary cover was the hottest point... No knocking upon traffic opening up. If my memory is correct, I would say this is even cooler than carbed hi comp Evo engine. Mine's fully decatted though..
Last edited by uwiik; Nov 29, 2024 at 05:42 AM.
HDF Community Team
Joined: Mar 2017
Posts: 7,821
Likes: 4,381
From: Texas
That is nothing to be worried about. Normal behavior according to the owners manual.
The radiator fan kicks on at around 180F.
When I rode the other day it was 41F and I rode 75mph for 35 minutes straight. Engine temp on the display was 215F. When I ride the same route at 105F, engine temp is 243F. According to the service manual these are normal engine temps.
If you let your bike idle long enough temps will exceed 240F as the fan will not pull enough air to keep the coolant cool enough to keep the engine cool enough. Don’t do that.
The radiator fan kicks on at around 180F.
When I rode the other day it was 41F and I rode 75mph for 35 minutes straight. Engine temp on the display was 215F. When I ride the same route at 105F, engine temp is 243F. According to the service manual these are normal engine temps.
If you let your bike idle long enough temps will exceed 240F as the fan will not pull enough air to keep the coolant cool enough to keep the engine cool enough. Don’t do that.
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Cruiser
Joined: Jul 2022
Posts: 144
Likes: 154
From: Tennessee
That is nothing to be worried about. Normal behavior according to the owners manual.
The radiator fan kicks on at around 180F.
When I rode the other day it was 41F and I rode 75mph for 35 minutes straight. Engine temp on the display was 215F. When I ride the same route at 105F, engine temp is 243F. According to the service manual these are normal engine temps.
If you let your bike idle long enough temps will exceed 240F as the fan will not pull enough air to keep the coolant cool enough to keep the engine cool enough. Dont do that.
The radiator fan kicks on at around 180F.
When I rode the other day it was 41F and I rode 75mph for 35 minutes straight. Engine temp on the display was 215F. When I ride the same route at 105F, engine temp is 243F. According to the service manual these are normal engine temps.
If you let your bike idle long enough temps will exceed 240F as the fan will not pull enough air to keep the coolant cool enough to keep the engine cool enough. Dont do that.
I agree that its best to just not even look at the temp.
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HDF Community Team
Joined: Mar 2017
Posts: 7,821
Likes: 4,381
From: Texas
Thats just the engine temp. Head temps are usually around 300F and the oil temp is somewhere in between. Since the 24 models have added some minor liquid cooling, these temps are cooler than the Gen1 2017-2023 M8 engines.
Welcome to air-cooled motorcycles.
Seasoned HDF Member
Joined: May 2012
Posts: 32,934
Likes: 36,027
From: Carlsbad, CA
Harley began boasting about reduced engine temperatures when they introduced the M8s new cooling systems not only to improve rider comfort
"A Milwaukee 8 engine utilizes oil cooling to reduce engine temperature by circulating engine oil around critical components like the pistons and cylinder walls, effectively absorbing heat and transferring it to the engine's oil cooler, thereby lowering the overall operating temperature of the engine."
"Improved efficiency:
By effectively managing engine temperature, oil cooling enhances engine performance, longevity, and reduces the risk of engine damage from excessive heat. To deal with the heat issue, Harley reduced the exhaust gas temperature by 100°F (55.6 C) by introducing a better water cooling solution."
"A Milwaukee 8 engine utilizes oil cooling to reduce engine temperature by circulating engine oil around critical components like the pistons and cylinder walls, effectively absorbing heat and transferring it to the engine's oil cooler, thereby lowering the overall operating temperature of the engine."
"Improved efficiency:
By effectively managing engine temperature, oil cooling enhances engine performance, longevity, and reduces the risk of engine damage from excessive heat. To deal with the heat issue, Harley reduced the exhaust gas temperature by 100°F (55.6 C) by introducing a better water cooling solution."