Author Topic: Oil cooler question  (Read 751 times)

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Offline Dime

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Oil cooler question
« on: September 23, 2024, 04:59:17 AM »
At what point should I run an oil cooler?

Future plans will involve a 823 kit. Temperatures here don't get much higher than 25 Celsius.

There is one for sale locally for $100 Canadian. I am including pictures.

Should I grab it?

Thanks in advance

Offline newday777

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Re: Oil cooler question
« Reply #1 on: September 23, 2024, 06:13:38 AM »
As long as you aren't racing it you should be fine at those temps without a cooler and use 20w50 oil.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline Dime

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Re: Oil cooler question
« Reply #2 on: September 23, 2024, 06:17:07 AM »
As long as you aren't racing it you should be fine at those temps without a cooler and use 20w50 oil.


It might see the drag strip once but that is about it. I do ride hard but nothing stupid. No burnouts and the like

I knew 15w 40 Rotella T was a common thing to run in these bikes but that is the first I hears of 20w 50.

Offline CB750R

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Re: Oil cooler question
« Reply #3 on: September 23, 2024, 06:31:09 AM »
I’m running one on my 836 fully build motor in western Canada. Our summers are a lot hotter in the Okanagan and the cylinder walls are a lot thinner and a lot less thermal mass to dissipate heat so it was a good call for me.

That being said I went with an all new setup.

Offline Dime

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Re: Oil cooler question
« Reply #4 on: September 23, 2024, 06:40:47 AM »
I’m running one on my 836 fully build motor in western Canada. Our summers are a lot hotter in the Okanagan and the cylinder walls are a lot thinner and a lot less thermal mass to dissipate heat so it was a good call for me.

That being said I went with an all new setup.

You guys get the real hot summers out there. Here in Newfoundland, not so much LOL.

I will be boring it oversize before I go to a 836cc. I also wondered about a new setup vs used. Used on an oil cooler is a bit of a gamble for sure.

Offline PeWe

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Re: Oil cooler question
« Reply #5 on: September 23, 2024, 11:00:09 AM »
2018 was rather hot here with 30-32C during 3 weeks.
Oil tank thermometer very often at 120C where the red begins.
Dipstick thermometer from Yamiya. Tested in boiling water, 100C, so correct.

No problem for oil. Just change more often.
Synthetic live longer.
I tested 20W-60 during that period.

A racing bike at constant 6000-9000rpm with heavy accelerations followed by decelerations using gearbox really hard another thing.

I bought a Setrab oil cooler.
I had plans to add a thermostat, oil to cooler after 100C
Important to get oil up to temperature asap.
100C when condense (water) will leave the engine which is good.


I saw no use for street use. 1005cc, later 970cc with higher compression.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Dime

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Re: Oil cooler question
« Reply #6 on: September 23, 2024, 11:08:50 AM »
2018 was rather hot here with 30-32C during 3 weeks.
Oil tank thermometer very often at 120C where the red begins.
Dipstick thermometer from Yamiya. Tested in boiling water, 100C, so correct.

No problem for oil. Just change more often.
Synthetic live longer.
I tested 20W-60 during that period.

A racing bike at constant 6000-9000rpm with heavy accelerations followed by decelerations using gearbox really hard another thing.

I bought a Setrab oil cooler.
I had plans to add a thermostat, oil to cooler after 100C
Important to get oil up to temperature asap.
100C when condense (water) will leave the engine which is good.


I saw no use for street use. 1005cc, later 970cc with higher compression.

Thank you for the response. I think I won't need the oil cooler, especially right now in stock form.

Offline Tracksnblades1

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Re: Oil cooler question
« Reply #7 on: September 23, 2024, 11:24:17 AM »
Honda cb750F2-3 had a factory spacer (some called cooler) under the oil filter…
I’ll see if I can find a picture it’ll let me attach…🙄

Edit: you’ll need 7 & 9 and the oring and I think the oil filter bolt is different too…
« Last Edit: September 23, 2024, 11:30:11 AM by Tracksnblades1 »
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Offline HondaMan

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Re: Oil cooler question
« Reply #8 on: September 23, 2024, 11:35:47 AM »
Honda cb750F2-3 had a factory spacer (some called cooler) under the oil filter…
I’ll see if I can find a picture it’ll let me attach…🙄

Edit: you’ll need 7 & 9 and the oring and I think the oil filter bolt is different too…
It also requires the longer oil cooler bolt. You can get those at PartsNmore if you need one (I have one, too).
I've got one or two of those F2/3 'cooler plates' around here: they often get removed for weeping (10w40) oil on hot days.
Theoretically, at least, they spread the heat energy around a little bit more.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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Offline robvangulik

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Re: Oil cooler question
« Reply #9 on: September 24, 2024, 09:38:49 AM »
Honda cb750F2-3 had a factory spacer (some called cooler) under the oil filter…
I’ll see if I can find a picture it’ll let me attach…🙄

Edit: you’ll need 7 & 9 and the oring and I think the oil filter bolt is different too…
It also requires the longer oil cooler bolt. You can get those at PartsNmore if you need one (I have one, too).
I've got one or two of those F2/3 'cooler plates' around here: they often get removed for weeping (10w40) oil on hot days.
Theoretically, at least, they spread the heat energy around a little bit more.
I have one of those on my CB400/450 and it really works very well, a larger amount of oil combined with a larger surface area radiating heat makes the engine run cooler.

Offline Finnigan

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Re: Oil cooler question
« Reply #10 on: September 24, 2024, 11:03:34 AM »
Do you standard fuel line hose with the oil cooler?  I see the fittings are different on the radiator vs the adapter plate.

Offline CB750R

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Re: Oil cooler question
« Reply #11 on: September 24, 2024, 03:47:00 PM »
I’d use hose suitable for a transmission cooler will be rated for a hot liquid and will handle pressure. 
If you use fuel hose make sure it’s rated for fuel injection  as it’s designed for pressure.

Offline Tracksnblades1

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Re: Oil cooler question
« Reply #12 on: September 24, 2024, 04:29:21 PM »
I’d use hose suitable for a transmission cooler will be rated for a hot liquid and will handle pressure. 
If you use fuel hose make sure it’s rated for fuel injection  as it’s designed for pressure.

When replacing the fuel line on the old Lincoln SA200, I noticed the regular fuel line I picked up at O’Riely’s (for $8.79)
was rated for 150#. Also mentioned for application using Gasoline, diesel, trans oil, hydraulic oil, pvc, radiator overflow, etc, etc, etc… Just like the old stuff…

Might be an overkill in a gravity sediment bulb fuel application but that’s what was available…😁
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Offline CB750R

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Re: Oil cooler question
« Reply #13 on: September 24, 2024, 06:21:37 PM »
We sell fuel line both ways hence the suggestion. I personally used Russell pro classic hose but I have a different routing and cooler setup.

Offline marsbound

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Re: Oil cooler question
« Reply #14 on: September 26, 2024, 07:18:24 PM »
Jumping on this...I live in North Texas, where the temperatures in the summer can regularly get into the triple digits (Fahrenheit) for many, many days in a row. Is an oil cooler for my 400F warranted in this case?

Thanks.

Offline CB750R

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Re: Oil cooler question
« Reply #15 on: September 27, 2024, 06:28:40 AM »
Jumping on this...I live in North Texas, where the temperatures in the summer can regularly get into the triple digits (Fahrenheit) for many, many days in a row. Is an oil cooler for my 400F warranted in this case?

Thanks.


There has been A LOT of conversation on this topic on this forum over the years. You could spend hours reading all the rather heated conversations related to this if you dare.

 I’m not an expert on the 400f, but in general if your Sohc Honda is un modified and your not riding in stop and go traffic or riding at the limit (track or wot) you’re bike was probably fine riding your bike as designed. I have a modified bike, and have made changes to suit my engine mods and my peace of mind. I’ve observed a 10c drop in temps on the oil tank pre and post oil cooler install, which is great for me. 




Offline Mark1976

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Re: Oil cooler question
« Reply #16 on: September 27, 2024, 08:25:41 AM »
Jumping on this...I live in North Texas, where the temperatures in the summer can regularly get into the triple digits (Fahrenheit) for many, many days in a row. Is an oil cooler for my 400F warranted in this case?

Thanks.


There has been A LOT of conversation on this topic on this forum over the years. You could spend hours reading all the rather heated conversations related to this if you dare.

 I’m not an expert on the 400f, but in general if your Sohc Honda is un modified and your not riding in stop and go traffic or riding at the limit (track or wot) you’re bike was probably fine riding your bike as designed. I have a modified bike, and have made changes to suit my engine mods and my peace of mind. I’ve observed a 10c drop in temps on the oil tank pre and post oil cooler install, which is great for me.
  As stated above, if your doing your thing and changing the oil on regular prescribed intervals more than likely not. But like all of the things we do to our bikes the real question becomes, whatta ya wanna do? I'm not saying it's money well spent, but it is money spent well. I use one, that's just me...
Start with the end in mind...

Offline RAFster122s

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Re: Oil cooler question
« Reply #17 on: September 27, 2024, 03:10:33 PM »
Be aware of the heat you are subjecting the oil too in hot periods is good on air cooled bikes, a fresh change sometimes can be felt. Our bikes gearboxes are tough on oil so changing the oil more frequently in extended heat or before or during a hot spell can help these air cooled bikes. I live in the Tucson area and we have months of triple digits heat in summer so I change before summer and ride water cooled bikes with at least semi synthetic oil with grade to handle the heat. An air cooled bike depends on the oil and air to cool it...so the air cooled bikes are for less intense weather, besides, the water cooled bikes is also fuel injected and faster and more powerful, so I'm not staying out in the heat more than I have to be. The cooling vest quickly dries quicker and my tolerance for 105 and above temps and my safety goes down due to the heat exhaustion risk. 30 minutes to 45 minutes is fine but better to have shorter trips in extreme heat if you have to do it. That said, I intend to fit an oil cooler on my cb550 when I rebuild it to give it the ability to handle the heat better. I just need to improve my own tolerance for the heat too...
David- back in the desert SW!