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[Pan1]

Does anyone know the reason some of the M-8 bikes have twin cool and some do not. I have a 2015 CVO twin cam with twin cool and think it works very ( that is when the water pump is not craped out). Even some of the new CVO's do not
 have it. My local dealership told me the reasoning is front tire diameter and lower fitment but it doesn't make sense the factory would build some with it some without.

I have been thinking of trading for new bike but the RG model I am looking at does not have twin cooled.

[Para Bellum]

Only a guess:  Oil cooling keeps the visuals clean; no lower fairings needed.  Also, in the past (most years), only the models with stock Tour-Pak came with lowers.

When compared to twin-cooled, the oil-cooled bikes reduce weight and complexity.  That saves HD money on assembly line.  It saves consumers money on maintenance, too, although we know HD doesn't care about us, lol.

[grc]

Twin Cooled is more complex and more expensive than oil cooled.  I'd love to see some third party testing to see which system is most effective at keeping head temps in a tightly controlled range, but so far I haven't seen anything.  I'm pretty sure Twin Cooled would be a clear winner.  Btw, if you wind up buying one of the oil cooled models, I highly recommend you add the oil cooler fan if it doesn't come standard.  It should have been standard from the beginning, but as we all know it wasn't.  Oil coolers don't do much for you in stop and go traffic or plodding along at low speeds.

JMHO - Jerry

[Pan1]

Thank you for the resposes. I had theory the M-8 had more valve seat area to carry heat to the heads and the twin cooling wasn t needed but since they make both depending on model it doesn’t make sence.

[GregKhougaz]

The only twin cooled bikes appear to be the Ultras and the CVO Street Glide. All have lower fairings required for the radiators. Heavier bikes... greater engine load... more heat.

[Gandrtravis]

The only twin cooled bikes appear to be the Ultras and the CVO Street Glide. All have lower fairings required for the radiators. Heavier bikes... greater engine load... more heat.

The 18-19 street glides are not twin cooled just oil cooled they claim they don’t need them because the new bikes run cooler.

[J.D.]

The whole concept of adding coolant to a Harley v-twin, this hybrid air/water cooled engine, is just bizarre (not to mention unreliable).  Either go all in on water cooling (V Rod) or keep it off.  Just seems like an afterthought.

[SHRADER]

The 18-19 street glides are not twin cooled just oil cooled they claim they don’t need them because the new bikes run cooler.

The 2019 CVO Street Glide is Twin Cooled according to the HD Site. It has lowers for certain, and what looks to be a water pump cover instead of the oil cooler. Could be a misprint as that has happened before......

[GregKhougaz]

The 18-19 street glides are not twin cooled just oil cooled they claim they don’t need them because the new bikes run cooler.

I see that the 2018`s were not twin cooled. But the Harley website lists the new, 2019 CVO Street Glide as being twin cooled. I have not seen one yet.

Via Tapatalk

[grc]

The specs page does not call the 2019 SESG Twin Cooled, and the photo from the site I've cropped and attached to this post clearly shows the oil cooler of an oil cooled model.

Jerry

[ultrarider123]

I see that the 2018`s were not twin cooled. But the Harley website lists the new, 2019 CVO Street Glide as being twin cooled. I have not seen one yet.

Via Tapatalk

Unless they have completely redesigned the radiators/fans/plumbing and have them vented different, I don't see any evidence of twin cooling on the '19 CVO Street Glide.  There are speakers in the lowers on the SG, however.  The '19 CVO Road Glide doesn't have lowers.  There is the old, familiar venting on the CVO Limited so twin cooling there for sure.

Don't know what's going on there, Greg.

[SHRADER]

Me too neither but seeing the area grc blew up it does look like a cooler to these tired eyes..

I was going by what is clearly listed right below that picture on their site...

Heck Harley don't even know what it is....                                                       

[Threephase]

Looking at the pics, if they are twin cooled (wet heads) there is no side vent from the lower fairings to by the speakers to allow air flow over a radiator.

[Mickle]

No vents in this one.

[Pan1]

Is oil routed through passages around the exhuast valves luke the coolent is on wet heads?

[Para Bellum]

Is oil routed through passages around the exhuast valves luke the coolent is on wet heads?

Yes

[grc]

The whole concept of adding coolant to a Harley v-twin, this hybrid air/water cooled engine, is just bizarre (not to mention unreliable).  Either go all in on water cooling (V Rod) or keep it off.  Just seems like an afterthought.

A complete liquid cooled system would be preferable in my opinion, but they weren't willing to alienate the old Harley faithful by doing that.  In that case, water cooling just the hottest part of the engine does in fact make good sense.  The Twin Cooled bikes control head temps so much better than the totally air cooled versions they were able to retune the bikes for better performance and fuel economy without detonation.  You should also expect better reliability from the exhaust guides and valves with liquid cooling.

Once all us old farts are gone, perhaps they will join the 21st century and hang a small radiator on the front of whatever version of V-Twin they use.  You don't need to hide the radiator if it's done right, plenty of other brands have radiators without having to hide them behind lowers.  As always, Harley has allowed style to dictate instead of function.  If they were really good, they could learn how to do both.  So far, I'm not seeing evidence they are even trying.

JMHO - Jerry

[mark]

I think it's time for water-cooling, at least on the touring bikes.  I've evolved.

[scottt]

I think it's time for water-cooling, at least on the touring bikes.  I've evolved.

With today's speeds and traffic, water cooling makes sense. Air cooled V-Twin motors were introduced during a completely different era and reality.  Ask yourself, if you were designing a touring motorcycle motor what would it be? I'd bet it would not be air cooled.

Sent from my SM-J327T using Tapatalk

[kojak]

Twin cooled bikes run cooler and generate a little more power, tested by cycle world.

[TRS300]

Was poking around in the M8 section to see how things are going with the new motor and I ran across this thread.

I posted a thread in the Twin Cam section related to the water cooled heads on my 2015 CVO SG.  Although the project was about adding a water-cooled oil cooler to my bike the result was I learned a lot about the cooling capability of the twin cooled system.

http://sta-bul.com/projects/OilCoolerProjectPhase1.pdf

The water cooled "Precision Cooling" system actually works VERY well with a lot of unused cooling capacity wasted due to how it is implemented.  When I removed the thermostat from the circulation loop I saw a 20 deg drop on head temperatures.  And even after adding the water-cooled oil cooler into the loop the overall system temp was 20 degs lower at the valves and 10 degs lower in the oil bath.  Not to mention that the system cools off much faster after a high load warm up event.

I was no "sold" on the wet head till I did this work.  And the best thing about it is, if it fails your not stranded.  Just ride on.  It's probably the only good thing about it being a targeted cooling system instead of a 100% water cooled system.

The new M8s that are water cooled I heard have a variable speed motor on the pump.  If you can find a way to get that pump to operate at 100% all the time I suspect you will be surprised at how much more cooling you will see from the system al of the time.

Check out the charts in the report I posted.  You may find it interesting.

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