Air cooled vers water cooled

20 replies to this topic
  • Ronnie Mac

Posted March 17, 2004 - 07:45 PM


I know many of you have been riding more years then I have and was just wondering. Does it have to be watercooled to get the best overall performance, derability, or what. My last bike never overheated even after trail riding with muddy fins. I just worry every time I crash im going to tear of one of this things and just wonder if it is worth the cool up-to date look. So whats your two cents? :)

  • YamahaSteve

Posted March 17, 2004 - 08:18 PM


Water cooling is not for performance as in horsepower, but a side effect of it. If you have a motor cranking out 10HP you are not creating very much heat in the engine and therefore the air cooling system makes sense. When you get up to somthing like a 50HP 4-stroke, you are burning alot of fuel in there and the heat generated is tremendous. Water cooling at that point makes better sense. Now... You could air cool a WR450 engine. It just comes down to size and weight of the air cooling versus the water cooling. Plus the water system removes heat more effectively so you reduce the internal temperatures even more which helps the engine run longer...

I too worry about my radiators... I think I am going to buy some braces for them. I do kinda miss my TTR250 when it comes to simplicity, but the WR450 is just such a machine I could never go back just for simplicity :)

  • Guest_Guest_*

Posted March 17, 2004 - 08:20 PM


Honda XR's are bullet proof, but offer low performance compared to a water cooled motor. I rode a old KDX200 for 10+ years (air cooled) and wish I still had that bike :) Zero maintenance and climed like a goat :D

  • tp3dxf

Posted March 17, 2004 - 08:37 PM


When I got my 426 one of my fears was ripping off a radiator when I crashed. Maybe I have been lucky or my radiator guards work good but I have yet to damage a radiator. And believe me I have crashed the thing many times. I did recently crash and when I did I must have pushed my head pipe up against one of my radiator hoses. After about 30 miles it burnt a hole in the hose and started leaking on a trail ride. The WR has a coolant resivor which had plenty of coolant left to get me back to the truck and I had a full camelback if it came down to it.

It was a cheap fix but it did fail due to my not seeing the problem before hand. I think water cooling is the way to go. If your out riding and you start overheating and boiling coolant you'll know it. Where as with a air cooled bike it might be a little harder to tell that the motor is in real touble. And by the time it really tells you it may be to late.

  • Hamish

Posted March 18, 2004 - 12:42 AM


Air cooling is fine, but generally air cooled engine run slightly on the rich side to prevent detonation when they get really hot (slow work). You can tune a water cooled engine much closer to the ideal Af ratio due to the fact that the combustion temp is more constant. Not sure about the colder climates, but in oz a lot of people weld extra fins onto theXR650 heads to help keep them cool. Even when I ran into a tree in my YZ250 :) it only bent the radiator at the mounts... bent it back again and it was fixed.


  • jchantzWR400F

Posted March 18, 2004 - 04:27 AM


Don't worry too much about it. The air-cooled bikes overheat just can't tell by looking. Nothing to boil over. You can tell by the oil when you change it though.

  • wjc2003

Posted March 18, 2004 - 02:32 PM


I was told or read somewhere that air cooled engines had a loss of power towards the end of a moto and that's why we have liquid cooling.I'm not a racer but I've been riding air cooled 400cc or bigger 2 strokes since '76 and I never felt like I didn't have enough power. Too bad someone doesn't make a high performance,air cooled dirt bike. 2 stroke or 4 stroke,either one would be alright with me.

  • JVP

Posted March 18, 2004 - 04:10 PM


Heat robs power. :) Having a constant engine temperature lets the engine designers use lighter weight materials and closer tolerances. It is basic thermodynamics. Nikaceled cylinders would never have happened without a water cooled engine.

  • Indy_WR450

Posted March 18, 2004 - 05:18 PM


Water cooled! :D :) :D

  • SMD

Posted March 18, 2004 - 05:29 PM


I would never go back to air cooled off road bike period!

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Ronnie Mac

Posted March 19, 2004 - 08:22 PM


I really thought I would get a neg feed bk for water cooled..But all have been pos. Shurly someone thinks air is better than watter!!

  • YamahaSteve

Posted March 19, 2004 - 09:56 PM


Well, in my first post I outlined the merits of each sytstem (in a roundabout way)... To your point of expecting more positive reactions to air cooling, I personally think air cooled is a better way to go for an offroad bike... it is simpler and lighter with less moving parts. Now, with that said you need water cooling on these high performance engines for reasons already outlined before (more heat removal/better cooling and more consistent cooling). So, I would take an air cooled with all other things being equal. But since you need the water cooling for these newer, more powerful bikes, I will take the water.

  • crf250_rider

Posted March 19, 2004 - 10:37 PM


you think an air cooled bike is lighter? :)
i dont think soo man !!

  • jwriott

Posted March 20, 2004 - 07:03 AM


I think your first post was really confusing and didn't make sense. :)

Water cooling does give you an enormous performance advantage in several ways. 1st, the engine can be designed to tighter tolerances and higher compression giving you more hp. 2nd, since the temperature remains constant, you don't see a decrease in performance during operation like you do with air cooled. I had 2 air cooled street bikes and they would overheat under hard use and the performance would go way down. 3rd, if maintained correctly, a water cooled engine should far outlast an air cooled engine.

Many of the higher performance air cooled engines run an oil cooler because air cooling alone isn't enough. This also has the side benefit of carrying additional oil as well.

I've had a bunch of water cooled bikes and run guards and have NEVER trashed a radiator. I crash hard and anyone that's ridden with me can attest to that. Ask yzman400. :D

  • kirkw

Posted March 20, 2004 - 07:29 AM


As many have alluded to, the most important part of combustion engines is temperature. If the engine is too hot or too cold it will result in a leaner or richer condition, repsectively, hence loss of power. Water cooling allows there to be a more constant temperature environemnt the engine can be tuned for to gain greater consistant performace. Think of cars, they have thermostats that force them early on to heat the engine quicker and then gradually open the thermo once it reaches target temp. If it goes over the temp there are fans. All to regualte temperature and get way more power out of the same dispalcement. For emaple and old VW air cooled 1800 might produce mid 60hp. A more recent honda water cooled 1800 could produce at least twice that. Overly simplistic example, but you get the idea. Watercooled is the only way to go if you want more power :)

  • MrBlahh

Posted March 20, 2004 - 03:00 PM


That's not a very good argument about an air cooled vw vs liquid honda

how bout an air cooled porsche 911 vs that same honda?

  • wjc2003

Posted March 20, 2004 - 05:50 PM


You're right!I was thinking the same thing.

  • wjc2003

Posted March 20, 2004 - 05:56 PM


In 1983 I bought a CR480 (air cooled) that weighed 226 lbs. A friend has it now and it still kicks a$$.

  • Ronnie Mac

Posted March 20, 2004 - 06:48 PM


How can you tell if over-heating(fouling plugs?)

  • crf250_rider

Posted March 20, 2004 - 07:06 PM


No, it pretty much starts runin like crap , wont perform normally and it will shut off when you let off the gas and stuff like that


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.