Engine Temperature?
Elite HDF Member
Joined: Aug 2008
Posts: 4,133
Likes: 125
From: Japan
Omaha has given the most sensible answers here. I've seen guys with temp gauges, oil coolers, head fans and all kinds of other usless gadgets on their bike to try and reduce their worry. You don't need all that ****. You just need to set up your motor so it's tuned well and breathing. If you want steady, worry-free temps get a bike with a radiator. It stays within a specified temp range and it looks better than bolting all that other nonsense on a Harley...
Oil temps don't tell the whole story, anyway. Head temp is what matters and they are good to over 350F. I have my T-Max set to throw the engine light at 325. The only time it has ever come on is when I put the stock mufflers back on my cammed open intake motor to take it to emissions inspection.
Oil temps don't tell the whole story, anyway. Head temp is what matters and they are good to over 350F. I have my T-Max set to throw the engine light at 325. The only time it has ever come on is when I put the stock mufflers back on my cammed open intake motor to take it to emissions inspection.
Outstanding HDF Member
Joined: Jan 2014
Posts: 2,181
Likes: 488
From: Central California
All I do is put in a meat thermometer after a ride. That'll give you a snap shot of what oil temp is. Just take off the cap, stick the probe down in the oil and see what it is. No need to clutter up the bike.
If it's really really hot consistently after checking it from time to time, then you know it needs attention. If it runs under 230 or less, it's good to go.
I've used a digital pyrometer because I happen to have one. More accurate than a cooking thermometer, but even so it's typically within 5 degrees.
My carb'd '02 Sporty was around 190 on average. Some days a little hotter, some days a little cooler. I'd call that dang near perfect. My Triumph Bonneville with the factory EFI tune was in the neighborhood of 240-250. A little on the hot side. So I put Motul 15W/50 motorcycle racing oil in it because it's made to run that hot or hotter. My Softail runs about 220 on average. Neither of my HD run really hot, so I usually run Brad Penn Semi synth racing oil in 'em. Mostly because I buy a lot of that for my drag race car.
The thing about gauges is that you begin to worry about it. I don't want that during a ride. I'm out there to enjoy the ride, not worry about minor fluctuations in temp or pressure
If it's really really hot consistently after checking it from time to time, then you know it needs attention. If it runs under 230 or less, it's good to go.
I've used a digital pyrometer because I happen to have one. More accurate than a cooking thermometer, but even so it's typically within 5 degrees.
My carb'd '02 Sporty was around 190 on average. Some days a little hotter, some days a little cooler. I'd call that dang near perfect. My Triumph Bonneville with the factory EFI tune was in the neighborhood of 240-250. A little on the hot side. So I put Motul 15W/50 motorcycle racing oil in it because it's made to run that hot or hotter. My Softail runs about 220 on average. Neither of my HD run really hot, so I usually run Brad Penn Semi synth racing oil in 'em. Mostly because I buy a lot of that for my drag race car.
The thing about gauges is that you begin to worry about it. I don't want that during a ride. I'm out there to enjoy the ride, not worry about minor fluctuations in temp or pressure
Last edited by Mike Lawless; Aug 26, 2015 at 07:21 PM.
Road Warrior
Joined: Oct 2012
Posts: 1,358
Likes: 220
From: Dallas
I have an analog oil temp gauge on mine and I love it. It's functional and it looks good. I'm not constantly checking it or anything but I like to know what's going on with my bike. I also have a power vision to check engine temps if I feel like it. Problem with that is it doesn't look good and I'm constantly checking it if I have it on the bike.
Road Master
Joined: May 2010
Posts: 816
Likes: 57
From: Rijssen, the Netherlands
Not true. Supposed that Syn-3 oil is used, the safe temperature of the oil must not exceed 149 C (300 F). Mobil V-Twin synthetic oil remains stabile even at 175 C (345 F) . These temps may frighten you, but we are talking about technical issues, not emotional issues. Here in Saudi my oil temp is reguraly around 250 with oil cooler (air cooled 88B and 96ci) and 270-275 without an oil cooler on a Limited 2015 Twin Cooled, all after city rides with a lot stop and go.. Nothing to worry about, even not with Syn-3 of Harley, which has a lower safe stability temp than some other brands. But still 300F. But, if it would be these temps the entire year round I would defenitely go for an external oil cooler when these are on the market for the Twin Cooled bikes. In winter the engine temps lower as well, till 240-250F without oil cooler and till 220 with oil cooler. For the air cooled bikes I have chosen for an oil cooler (fan assisted, side mount) not for technical reasons but mostly for crotch protection against the heat.
Last edited by Bart van der Meulen; Aug 27, 2015 at 06:19 AM.
Cruiser
Joined: Apr 2015
Posts: 166
Likes: 1
From: houston
borrow a laser temp device and aim it at the heads if you really want to know what temps they run. you can move it around and even find hot spots if you like and record the temps for a log sheet. That should keep you busy for some time.
Road Master
Joined: May 2015
Posts: 791
Likes: 221
From: sf bay area ca
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Outstanding HDF Member
Joined: Oct 2006
Posts: 2,263
Likes: 36
From: Georgia Mountains
I was always told you needed at least 170* to burn off the condensation