Engine seems especially hot
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Cruiser
Joined: Feb 2007
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Engine seems especially hot
Purely unscientific and going with a gut feeling, but my '97 Softail (cam, headwork, S&S carb and cleaner, Thunderheader, all done by PO) with 20k miles seems to run exceptionally hot. I have two other evos (both with either cam, head and or high compression pistons done by POs) which run much cooler. How do I know? By the 'damn this is hot under my legs' test. What would cause an engine to run too hot? (BTW, the plugs look pretty and tan colored, but the pipes have a purplish color at the heads and the black is flaking off the engine near the heads as well).
Outstanding HDF Member
Joined: Mar 2010
Posts: 2,877
Likes: 2
From: Hallsville, Tx.
Use a meat thermometer in the oil right after a ride or, better yet an infra red thermometer. Mine runs just under 200 even when ambient is in the 90s. I think you need to know what temp for sure. A guy on ebay makes a nice analog dip stick thermo for evos, might even be something cheaper available for your ST. peace of mind.
Tourer
Joined: Apr 2010
Posts: 293
Likes: 7
There can be a number of culprits.
But some common ones are......
Too lean. Check your jet sizes. It pays to remember that lean is mean, but not necessarily cool running and smooth.
Timing too far advanced. this exposes the burning mixture to the engine internals for longer, so there is a greater heat transfer(and, accordingly, power losses, obviously)
Bear in mind, that when an engine is working harder, more heat may be generated. Now if the cooling system is working well(in your case, the engine fins) then you would expect to notice more heat radiating off the motor. This means all is in order.
When the evo was first introduced, many riders thought there was something wrong, as the engine was able to dissipate heat so much more effectively that they were used to. HD went to great pains to point out that it was a sign of effective cooling, not poor cooling.
Your issue is likely a combination of factors.
Checking the oil temp is a good idea, and those temp dipsticks have been around for a long time. I do not think they all work really well though.
But some common ones are......
Too lean. Check your jet sizes. It pays to remember that lean is mean, but not necessarily cool running and smooth.
Timing too far advanced. this exposes the burning mixture to the engine internals for longer, so there is a greater heat transfer(and, accordingly, power losses, obviously)
Bear in mind, that when an engine is working harder, more heat may be generated. Now if the cooling system is working well(in your case, the engine fins) then you would expect to notice more heat radiating off the motor. This means all is in order.
When the evo was first introduced, many riders thought there was something wrong, as the engine was able to dissipate heat so much more effectively that they were used to. HD went to great pains to point out that it was a sign of effective cooling, not poor cooling.
Your issue is likely a combination of factors.
Checking the oil temp is a good idea, and those temp dipsticks have been around for a long time. I do not think they all work really well though.
Outstanding HDF Member
Joined: Mar 2010
Posts: 2,877
Likes: 2
From: Hallsville, Tx.
My oil temp hasn't gone over 200 this summer. I checked calibration of my thermometer and it's within 1 degree F. My Sportster (2002 1200S) used to go up to 215 or 220 on a hot day. The present day twinks can run up to 300 or better! Better people than me should answer the "how high before worrying?" part.
Road Warrior
Joined: Mar 2007
Posts: 1,912
Likes: 2
From: Cave Creek, AZ
I know what you mean about the leg heat test, so I bought the laser heat gun at Harbor frieght, maybe it was a piece of crap, but it always showed my bike was running around 260, which scared the crap out of me, but the real problem was where was I supposed to get the right temp from? where on the motor was it the right side or the left side? was it under the spark plugs or the fins? I was running the DFO and I messed with the settings, but no change. The bike kept running strong and it had no issues, but I always wondered. 96 that dip stick for an evo was something I always wanted but was never available, but on my next bike I'll get one and an oil cooler here in Phoenix, AZ.
Tourer
Joined: Sep 2009
Posts: 309
Likes: 2
From: Tegucigalpa
I went throught the manual, clymer's 84-99 softail manual, and there are some things to check for engine overheating
-incorrect carburetor adj or jet selection
-ignition timing retarded
-faulty vacumm operated electric switch
-improper spark plug heat range
-oil level low
-oil not circulating properly
-valves leaking
-heavy engine carbon deposit
I can't find anywhere in the manual where it says "normal operating engine temp"
I just found an oil table with "Ambient Operating Temperature" for SAE20W/50, SAE 50&60, and they all have a maximum of 100şF
So basically... check ur oil for temperature, not the engine.
As for the temp... I guess that 100şF might be the maximum temp, after that, oil loses it's viscosity and u can have an engine breakdown... If u see ur oil reaching those temps, u need an oil cooler ASAP.
-incorrect carburetor adj or jet selection
-ignition timing retarded
-faulty vacumm operated electric switch
-improper spark plug heat range
-oil level low
-oil not circulating properly
-valves leaking
-heavy engine carbon deposit
I can't find anywhere in the manual where it says "normal operating engine temp"
I just found an oil table with "Ambient Operating Temperature" for SAE20W/50, SAE 50&60, and they all have a maximum of 100şF
So basically... check ur oil for temperature, not the engine.
As for the temp... I guess that 100şF might be the maximum temp, after that, oil loses it's viscosity and u can have an engine breakdown... If u see ur oil reaching those temps, u need an oil cooler ASAP.
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Stellar HDF Member
Joined: Apr 2009
Posts: 3,039
Likes: 11
From: Northern Ontario
I have the oil temo dip stick for the tank as well as my buddies 87 fxr same dip stick and we're always the same temp , usually just under 200.
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Thread Starter
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Cruiser
Joined: Feb 2007
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....which, according to the "Ambient Operating Temperature", would be twice as high as allowable. That doesn't make sense. (My '89 with high compression pistons runs at about 175 via the dipstick thermo)
Road Captain
Joined: Apr 2005
Posts: 535
Likes: 14
From: Highspire Pa
Ultima recommends the oil temperature be kept between 165°F-205°F
If you are concerned about the oil temperature you can have your oil analyzed and they will tell you if the oil had reached a point where it was too hot, as well as the viscosity level at a couple different temperatures. They can tell if the air and oil filter is working properly, but I use it more for the engine wear levels.
I had different 2 lifter assemblies go bad on our Ultima 113" within about 14000 miles and both times the iron levels were well above normal wear. I also had excessive wear on my rocker supports that gave higher aluminum levels. The cost is about $25.00 and they send you a shipping container free. The independent lab I use is called Blackstone and they have a lot more information on their web site, along with various samples that explain far better than I am here.
http://www.blackstone-labs.com/index.php
On line, I found that oil analysis reports can be a little like dyno reports, just pieces of paper that some individuals will use in an ongoing effort to prove their oil or engine is better than yours but it can be used as an additional diagnostic tool.
joe
ON EDIT: If I lived closer to a good, trustworthy Indy shop like Miacycles, a regular poster here in the Evo section, I may not have needed the oil analysis to help me determine there was a problem.
If you are concerned about the oil temperature you can have your oil analyzed and they will tell you if the oil had reached a point where it was too hot, as well as the viscosity level at a couple different temperatures. They can tell if the air and oil filter is working properly, but I use it more for the engine wear levels.
I had different 2 lifter assemblies go bad on our Ultima 113" within about 14000 miles and both times the iron levels were well above normal wear. I also had excessive wear on my rocker supports that gave higher aluminum levels. The cost is about $25.00 and they send you a shipping container free. The independent lab I use is called Blackstone and they have a lot more information on their web site, along with various samples that explain far better than I am here.
http://www.blackstone-labs.com/index.php
On line, I found that oil analysis reports can be a little like dyno reports, just pieces of paper that some individuals will use in an ongoing effort to prove their oil or engine is better than yours but it can be used as an additional diagnostic tool.
joe
ON EDIT: If I lived closer to a good, trustworthy Indy shop like Miacycles, a regular poster here in the Evo section, I may not have needed the oil analysis to help me determine there was a problem.
Last edited by pajoe; Aug 26, 2010 at 04:24 AM.
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