Water Cooled vs. Air Cooled
#51
09-11-2011, 08:30 PM
Ultimate HDF Member
I'm no engineer, so this is layman's speculation. But the addition of a cooling system would add significant weight--for the radiator, fan and fan motor (if so equipped), thermostat, etc. and the coolant. (Water weighs 8 pounds per gallon, have no idea about water/antifreeze mix.) So adding a system like that to the same sized engine would decrease the power to weight ratio, wouldn't it?
And how about this lawsuit--radiator hose breaks and shoots superheated water and steam onto motorcyclists legs. When a hose breaks in a cage, the spray is contained by to the engine compartment.
Just like McDonalds can't make cold coffee so you can safely spill it in your lap, Harley can't make a cool engine so that you can safely touch the pipes after it has been running.
And how about this lawsuit--radiator hose breaks and shoots superheated water and steam onto motorcyclists legs. When a hose breaks in a cage, the spray is contained by to the engine compartment.
Just like McDonalds can't make cold coffee so you can safely spill it in your lap, Harley can't make a cool engine so that you can safely touch the pipes after it has been running.
Last edited by fat_tony; 09-11-2011 at 08:37 PM.
#52
09-11-2011, 10:58 PM
Elite HDF Member
I don't feel a need for water cooled, we're quite happy with our bike.
But, how many of us pro-aircooled would mind a 4-valve per cyl., 103ci water cooled V-twin with 4-valve heads making 120hp from the factory?
But, how many of us pro-aircooled would mind a 4-valve per cyl., 103ci water cooled V-twin with 4-valve heads making 120hp from the factory?
#53
09-12-2011, 07:40 AM
Cruiser
i would just like to say, if my souped up lawn mower can stomp a mud hole in your bikes butt , then what does that have to say about your bikes design??? just wandering... five year and haven't had a problem with the cooling system yet at 30,000 miles... i've split rear wheel bearing casings... the only issue i've been having is the rear brake switch, and a damn fuel gauge malfuntion repeatedly...
#54
09-12-2011, 07:44 AM
My old Magna V65 with it's 16 valves took around three hours to do a valve job.
Draining the coolant to rotate the radiator out of the way to clear the front valves, was part of the process.
I think it only had 110 HP. That bike would straight arm you to the rear of the seat if you got on it from a stop or slow rolling start.
I don't miss it in the least. I don't have a need for speed any more.
Draining the coolant to rotate the radiator out of the way to clear the front valves, was part of the process.
I think it only had 110 HP. That bike would straight arm you to the rear of the seat if you got on it from a stop or slow rolling start.
I don't miss it in the least. I don't have a need for speed any more.
#55
09-12-2011, 09:50 AM
Nobody will force Harley to stop making aircooled engines, the type of cooling an engine has is NOT regulated by any gummit faction. What is regulated by the EPA is emmisions coming out of the tail pipe. The hotter an engine operates (within reason) the more efficiant it becomes. This why most modern auto engines operate at closer to 230 degrees, as opposed to years back when most were kept to around 180 Degrees.
#56
09-12-2011, 04:25 PM
Extreme HDF Member
I'm 70 and put two bikes with Evo's, three with TC96's, and one TC103. I'm good for the rest of my days on earth.
But for grins and giggles I put a water cooled one in with them.
But for grins and giggles I put a water cooled one in with them.
#57
09-12-2011, 05:25 PM
I've been thinking about a couple of threads here that have touched on the issue of water cooled vs. air cooled engines. I have an Ultra Limited, and it's very cool 
. Yes, it runs hot in stop and go traffic, but it's a very good bike.
In thinking about it, if water cooled engines become mandated, would air cooled bikes likely go up or down in value?
Also, yes, heat is shed off water cooled engines, but the difference is inside, I think, where the core engine parts are kept at a more constant temperature.
Guessing as a non-engineer (though I've slept with one for decades):
Air Cooled: Has to be built to looser tolerances to allow for the greater temperature ranges, and hence metal expansions, from a hot to a cold engine, so the engine is less efficient, gets relatively worse gas mileage, and is allowed to run hotter.
Water Cooled: Can be built to tighter tolerances because the water cooling can keep internal parts at a more constant temperature, so the engine is likely more efficient—and also should get better gas mileage than a comparable air cooled engine.
If Harley ever switches to water cooled engines, I'm not sure I'd be concerned about it except as per the value of my air cooled bike, because I see pros and cons. It's more complexity, so there's something more to break on a long haul or out in the middle of nowhere. Hopefully they'd do it well, so it wouldn't break. Much. But if they did it well, then it could help me in stop-and-go traffic when the freeways get clogged.
I've never had to pull over due to heat, but I could see that it could happen if the traffic were real bad. As it is, when I ride someplace through Los Angeles, for example, I check the traffic on my iphone and try to pick a route that is the least likely to have a traffic jam.
. Yes, it runs hot in stop and go traffic, but it's a very good bike.In thinking about it, if water cooled engines become mandated, would air cooled bikes likely go up or down in value?
Also, yes, heat is shed off water cooled engines, but the difference is inside, I think, where the core engine parts are kept at a more constant temperature.
Guessing as a non-engineer (though I've slept with one for decades):
Air Cooled: Has to be built to looser tolerances to allow for the greater temperature ranges, and hence metal expansions, from a hot to a cold engine, so the engine is less efficient, gets relatively worse gas mileage, and is allowed to run hotter.
Water Cooled: Can be built to tighter tolerances because the water cooling can keep internal parts at a more constant temperature, so the engine is likely more efficient—and also should get better gas mileage than a comparable air cooled engine.
If Harley ever switches to water cooled engines, I'm not sure I'd be concerned about it except as per the value of my air cooled bike, because I see pros and cons. It's more complexity, so there's something more to break on a long haul or out in the middle of nowhere. Hopefully they'd do it well, so it wouldn't break. Much. But if they did it well, then it could help me in stop-and-go traffic when the freeways get clogged.
I've never had to pull over due to heat, but I could see that it could happen if the traffic were real bad. As it is, when I ride someplace through Los Angeles, for example, I check the traffic on my iphone and try to pick a route that is the least likely to have a traffic jam.
#58
09-13-2011, 06:10 PM
I'n not sure it's tolerances in manufacture that are different but having a water cooled engine certainly stabilises the temperature better and allows for more consistency in the engine and in it's combustion. As for noise, for the same pipes, air cooled is nosier than water cooled as the water jacket muffles the mechanical engine sound quite a bit. But Harley's unique noise is all about the single throw crank and not because it's air cooled. BMW moved their boxer from air to oil cooled a while back and it did not really effect the residual values of the air cooled bikes.
#59
09-13-2011, 07:18 PM
On a Vulcan when the coolant temperature goes up beyond (212 ∼ 230°F), the radiator fan starts. When the temperature is below (207 ∼ 217°F), the fan stops.
Last edited by cocheese72; 09-13-2011 at 11:14 PM.