The 2021 Ultimate Fix to the Heat Issue

aniwack

Site Supporter
Joined
May 13, 2018
Messages
602
Location
Atlanta, GA
Bike
05A/07A/09PA
STOC #
9062
I’ve decided to wade back into this issue (because I’m a glutton for punishment Larry says) and tell you the sure fire way to resolve your heat problem once and for all. I’ve used this method on five bikes and have five happy owners.

STEP 1: USE A THICKER OIL.
Its that easy. The problem is the Honda 5W-20 oil is just too thin for how hot these engines get under the covers. My Shadows and V-Stars were air-cooled so this is a completely different type of fix. The thinner oils are fine for those open air engines. But we need the oil to pull the heat away from the block. So how do we do that?

15W-40.

Yup, I’m that crazy AND IT WORKS! Pair it up with a Mobil 1-110A and you’ve just solved 80% of the problem. My bikes idle cooler and lower than Honda Oil bikes. “BUT ITS DIESEL OIL!!“ you say. That’s more of a marketing gimmick. The thicker oil does work! So what do we do now with that heat, it must go somewhere...

STEP 2: DON’T NEGLECT YOUR COOLING SYSTEM.
When was the last time you swapped out the thermostat? If you can’t remember, it’s a good time to do it. The heat in the oil transfers to the coolant and goes to the radiator. The radiator dumps that heat down the vents and out. The fans work less because the bike is in a natural balance. Your bike will run cooler and (secret result) you will get a better MPG. I’ve got cooler bikes running better than 48.5 MPG. I have achieved frame temperatures of 86* at the knee point. While you are at it, fresh coolant never hurts.

The heat issue is a very simple fix. There is absolutely no need to cut the cowls or take drastic action installing insulation under the tank. There is a website that does a tutorial on how to do all that insulation. DON‘T DO IT! I’ve already had a horror story with two bikes with insulation that the trapped heat melted sensor connectors to the harness and the main harness actually bubbled!

Oil and the thermostat is the easiest and cheapest fix to deal with your heat problems forever.
 

dduelin

Tune my heart to sing Thy grace
Site Supporter
Joined
Feb 11, 2006
Messages
9,685
Location
Jacksonville
Bike
GL1800 R1200RT NC700
2024 Miles
008131
STOC #
6651
I’ve decided to wade back into this issue (because I’m a glutton for punishment Larry says) and tell you the sure fire way to resolve your heat problem once and for all. I’ve used this method on five bikes and have five happy owners.

STEP 1: USE A THICKER OIL.
Its that easy. The problem is the Honda 5W-20 oil is just too thin for how hot these engines get under the covers. My Shadows and V-Stars were air-cooled so this is a completely different type of fix. The thinner oils are fine for those open air engines. But we need the oil to pull the heat away from the block. So how do we do that?

15W-40.

Yup, I’m that crazy AND IT WORKS! Pair it up with a Mobil 1-110A and you’ve just solved 80% of the problem. My bikes idle cooler and lower than Honda Oil bikes. “BUT ITS DIESEL OIL!!“ you say. That’s more of a marketing gimmick. The thicker oil does work! So what do we do now with that heat, it must go somewhere...

STEP 2: DON’T NEGLECT YOUR COOLING SYSTEM.
When was the last time you swapped out the thermostat? If you can’t remember, it’s a good time to do it. The heat in the oil transfers to the coolant and goes to the radiator. The radiator dumps that heat down the vents and out. The fans work less because the bike is in a natural balance. Your bike will run cooler and (secret result) you will get a better MPG. I’ve got cooler bikes running better than 48.5 MPG. I have achieved frame temperatures of 86* at the knee point. While you are at it, fresh coolant never hurts.

The heat issue is a very simple fix. There is absolutely no need to cut the cowls or take drastic action installing insulation under the tank. There is a website that does a tutorial on how to do all that insulation. DON‘T DO IT! I’ve already had a horror story with two bikes with insulation that the trapped heat melted sensor connectors to the harness and the main harness actually bubbled!

Oil and the thermostat is the easiest and cheapest fix to deal with your heat problems forever.
Uh, if you say so.
 
Joined
Feb 2, 2014
Messages
1,854
Location
houston, tx
STEP 1: USE A THICKER OIL.
Its that easy. The problem is the Honda 5W-20 oil
So how do we do that?
15W-40.
Who in the world recommended 5w-20 for the ST?????

At a minimum, the official manual states 10-30.

EDIT: to be clear, are we referring to the
"heat issue on my legs" ...
or referring to an
"engine overheating" issue??

those are two different things
 
Joined
Oct 31, 2009
Messages
23
Location
Arkansas
Bike
2005 st1300/Victory
STOC #
8087
I’ve decided to wade back into this issue (because I’m a glutton for punishment Larry says) and tell you the sure fire way to resolve your heat problem once and for all. I’ve used this method on five bikes and have five happy owners.

STEP 1: USE A THICKER OIL.
Its that easy. The problem is the Honda 5W-20 oil is just too thin for how hot these engines get under the covers. My Shadows and V-Stars were air-cooled so this is a completely different type of fix. The thinner oils are fine for those open air engines. But we need the oil to pull the heat away from the block. So how do we do that?

15W-40.

Yup, I’m that crazy AND IT WORKS! Pair it up with a Mobil 1-110A and you’ve just solved 80% of the problem. My bikes idle cooler and lower than Honda Oil bikes. “BUT ITS DIESEL OIL!!“ you say. That’s more of a marketing gimmick. The thicker oil does work! So what do we do now with that heat, it must go somewhere...

STEP 2: DON’T NEGLECT YOUR COOLING SYSTEM.
When was the last time you swapped out the thermostat? If you can’t remember, it’s a good time to do it. The heat in the oil transfers to the coolant and goes to the radiator. The radiator dumps that heat down the vents and out. The fans work less because the bike is in a natural balance. Your bike will run cooler and (secret result) you will get a better MPG. I’ve got cooler bikes running better than 48.5 MPG. I have achieved frame temperatures of 86* at the knee point. While you are at it, fresh coolant never hurts.

The heat issue is a very simple fix. There is absolutely no need to cut the cowls or take drastic action installing insulation under the tank. There is a website that does a tutorial on how to do all that insulation. DON‘T DO IT! I’ve already had a horror story with two bikes with insulation that the trapped heat melted sensor connectors to the harness and the main harness actually bubbled!

Oil and the thermostat is the easiest and cheapest fix to deal with your heat problems forever.
What oil brand? 15W40? Is that a diesel oil?
 
Joined
Oct 31, 2009
Messages
23
Location
Arkansas
Bike
2005 st1300/Victory
STOC #
8087
Oil is oil. As long as it’s API CK-4, it doesn’t matter who’s sticker is on it.
I don't care about brands, the original poster, said " I know, it's Diesel oil" .
I can't figure how the oil he recommends is a diesel oil. I mean 15W40...is that the weight of diesel oil?
 
Joined
Feb 2, 2014
Messages
1,854
Location
houston, tx
I don't care about brands, the original poster, said " I know, it's Diesel oil" .
I can't figure how the oil he recommends is a diesel oil. I mean 15W40...is that the weight of diesel oil?
Research "Shell Rotella"

You joined 2009 ... no doubt you've seen all the oil threads
 

dduelin

Tune my heart to sing Thy grace
Site Supporter
Joined
Feb 11, 2006
Messages
9,685
Location
Jacksonville
Bike
GL1800 R1200RT NC700
2024 Miles
008131
STOC #
6651
Oil is oil. As long as it’s API CK-4, it doesn’t matter who’s sticker is on it.
API CK-4 is no longer certified for use in gasoline engines, not that it matters to the faithful. It was the previous CI series of API certifications that was so good. I ran API CK-4 and SL/SN Rotella 15w40 for more than 70,000 miles in my ST prior to the loss of API certs for spark engines with the change to CK-4.

When they took out the high ppm of zinc & phosphorous in the reformulation of 2016 it just became another oil sold cheap in the automobile and truck aisle. For many years diesel oils like Rotella in 15w40 and 5w40 had the highest ppm of zinc and phosphorus available, good for the flat tappet valve trains in many motorcycles, but not any more. CK-4 limits ppm of the good stuff to 1200 IIRC.

The internal Honda White Paper on oil put to rest the myth that thicker oils run cooler in liquid cooled engines. The study leading to the White Paper's conclusion was that 10w30 in liquid cooled Honda engines produced the coolest oil and cylinder head temperatures. In the good oil days of air cooled engines, thicker multiweight oils with 40 & 50 [running temperature] weight were recommended but a primary advantage of liquid cooling is the ability to tightly control operating temperature and no more than 30 is ever required or recommended for Honda liquid cooled street bikes for the last 15 years. Thicker viscosity oils cause more heat from internal friction and incrementally higher power losses as viscosity increases.
 
Last edited:
Joined
Apr 9, 2011
Messages
1,030
Location
Canton, GA
Bike
2006 ST1300
I have one of the “ hot” ST1300’s, and have gone through many , many trials of various ideas, schemes, new parts, etc., up to and including talking to Larry ( Igofar) to get his recommendations. I had a long list to work on!
However, it’s still hot bike to ride in any kind of warmish weather.
Thicker oil? Fresh thermostat? High state of tune? Been there, done that, have the receipts - but no cool running bike. Maybe SOME bikes respond to that, but mine didn’t.
 

Igofar

Site Supporter
Joined
Jan 8, 2011
Messages
7,120
Location
Arizona
Bike
2023 Honda CT125A
 

Kevcules

Site Supporter
Joined
Jul 16, 2016
Messages
1,404
Age
55
Location
NB Canada
Bike
2008 ST1300
EDIT: to be clear, are we referring to the
"heat issue on my legs" ...
or referring to an
"engine overheating" issue??

those are two different things
Exactly.....I went through the tune up, new oil, new antifreeze and thermostat dance and it's still hot. It's the "heat on my leg"s that is a nuisance similar to Klaproth's response.
 
Joined
Dec 6, 2018
Messages
1,074
Age
41
Location
UK
Bike
2002 ST1300A
STOC #
9004
This is clearly what happens when things get colder than normal in the US...
 
Joined
Jul 7, 2020
Messages
37
Age
42
Location
Jacksonville
I have one of the “ hot” ST1300’s, and have gone through many , many trials of various ideas, schemes, new parts, etc., up to and including talking to Larry ( Igofar) to get his recommendations. I had a long list to work on!
However, it’s still hot bike to ride in any kind of warmish weather.
Thicker oil? Fresh thermostat? High state of tune? Been there, done that, have the receipts - but no cool running bike. Maybe SOME bikes respond to that, but mine didn’t.
So your temp gauge runs intermittent into the red?
 
Top Bottom