overheating


20 replies to this topic
  • ScottWR450F

Posted April 30, 2005 - 07:16 PM

#1

Today I rode with my 6 yr old son and he rides about 3 miles an hour through the woods. I was using my clutch a lot and my bike started to overheat and smoke. The reservoir had the correct amount of coolant. Any suggestions? 05 WR450F

  • DCaddy

Posted April 30, 2005 - 07:53 PM

#2

Don't ride 3mph, Its hard I have a 10 year old on a xr100 and you gotta move that thing. While I am waiting on him I get the radiator headed up wind and hope for the best. Other than that I use the e-start while I wait for him to catch up. Your bike was made to run hard. Deal With It.

  • gregwr450f

Posted May 01, 2005 - 02:17 AM

#3

Not made for going that slow, they need air flow.
Put heat reflective tape on the lower part of your rad to reflect the heat coming of the header pipe.

  • offday

Posted May 01, 2005 - 04:19 AM

#4

Best simple fix? start running "engine ice" coolant, its about $14 half gallon, It can lower your temp up to 15 degrees. That, and see if you can add a cooling fan to you bike. I know they make the kit for the KTM but not sure about the WR. but the kit from ktm is about $140. Also try letting the little guy get up ahead a bit while you wait. Then ride up past him aways and wait again. The magic button makes it a snap :naughty: :naughty:

  • swells454

Posted May 01, 2005 - 04:25 AM

#5

If you do a lot of slow (first gear) riding or idling at stops for extended periods...it will boil over. I ride with my kids a lot and it always happened...also in the tight woods after about 20 minutes. I used red line water wetter...same results. Then I tried engine ice...same results (maybe lasted a few minutes longer). I finally switched out to Evans NPG+. That cured the problem. Now it can idle for an hour w/o overheating and as I understand it the oil temps are staying in an acceptable level.
If you do a search on Evans you will find opinions on both ends of the spectrum. A lot of guys here run it with good results. It works great for me. It is about $27 bucks a gallon but you never have to change it. I got mine from mooneyes. :naughty:
Good luck, Steve.

  • offday

Posted May 01, 2005 - 05:05 AM

#6

If you do a lot of slow (first gear) riding or idling at stops for extended periods...it will boil over. I ride with my kids a lot and it always happened...also in the tight woods after about 20 minutes. I used red line water wetter...same results. Then I tried engine ice...same results (maybe lasted a few minutes longer). I finally switched out to Evans NPG+. That cured the problem. Now it can idle for an hour w/o overheating and as I understand it the oil temps are staying in an acceptable level.
If you do a search on Evans you will find opinions on both ends of the spectrum. A lot of guys here run it with good results. It works great for me. It is about $27 bucks a gallon but you never have to change it. I got mine from mooneyes. :naughty:
Good luck, Steve.


Hey could tel me a little more about the NPG+? Ive never had a problem with my bike but my son's 426 will sometimes puke a little out the overflow. It's never "overheated" per say, where it's actually boiling over and steaming. I'm running the engine ice in it now. but I'm not familiar with the NPG+ :naughty:

  • gregwr450f

Posted May 01, 2005 - 05:09 AM

#7

Are these products making the bike run cooler or do they just have a higher boiling point?

  • swells454

Posted May 01, 2005 - 05:25 AM

#8

Evans NPG+ is a waterless coolant that raises the boiling point.
http://www.evanscooling.com/
Do a search for evans on this site and you should be able to find enough wisdom to help w/ your decision. I am no expert...it works great for me and after weighing all the pro's and con's...I decided to give it a try. :naughty:

  • offday

Posted May 01, 2005 - 05:35 AM

#9

Thanks for the info. But I still am concerned about the NPG+. It has a higher boiling point @370 degrees. Great. but are bikes designed to run in that range? Maybe the whole point of boiling over is to let you know that damage is right around the corner if you don't get it cooled down, or shut it down and let it cool. I admit I have no idea. will the engine just continue to run in a "danger zone" with no indication? Any thoughts? :naughty:

  • gregwr450f

Posted May 01, 2005 - 05:51 AM

#10

I don't know the answer to that either, I posted the question in the general forum, hopefully get some good answers there.

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  • swells454

Posted May 01, 2005 - 06:17 AM

#11

Following is a excerpt from another thread I found that helped me to make up my mind. The members name who typed it id qadsan and seems really knowledgable when it comes to these thumpers. I typed in " oil temp evans" in the search box. :naughty:

Re: 650R Overheating at low speeds

It's pretty normal for this to happen, especially on a stock bike. If your bike is uncorked (airbox restrictors removed, non-EPA manifiled installed, larger exhaust tip, carb rejetted, etc), then it will boil over a lot less frequent.

Some people buy a Kawi KX80 rad cap that increases the pressure in the system which in turn raises the boiling point, but that will just prolong the enevitable. A very few people have gone to the extreme of adding a fan, but there's really no need for that. Sometimes the thermostat can stick and that might be a problem area, but some people (dependong on their riding environment) run them without thermostats with good success. Some people experiment with different coolants and some have had good success with this approach, but this approach might not be necessary.

I never used to have any boil over issues with my bike and then it happened a few time to me when I went riding with some small kids on the hotter days. I switched over to Evans NPG+ coolant quite a while ago. It has a boiling point of ~375 F which is much higher than the 50/50 (H2O/EG) mix. Just because it has a higher boiling point doesn't mean you'll ever get it to that level and I'm not a bit worried with this product as I've been running the NPG stuff for years in some of my cars with good results. It's also a lifetime coolant. I also did a bit of testing after pouring the Evans NPG+ in my bike. I drilled & tapped the frame plug (for oil temp) and the boss on the water pump (for coolant temps) for 1/8 NPT. Then I captured the temperature information using a portable datalogger on a few rides and decided to keep the Evans NPG+ installed because the temps stayed in check during the summer months while riding in the SoCal & Nevada deserts and the temps never got out of control even during extended periods of idling. The Evans NPG+ is a waterless coolant and has some advantages over the tradition 50/50 mix, but it's far from the perfect coolant. The NPG+ doesn't cool as well at lower temperatures as the normal 50/50 mix, but it continues to work when the 50/50 mix boils and that was important to me along with it being a lifetime coolant. Another downside to the NPG+ is that you cannot add water to your cooling system, so if your bike does get a leak due to your rad smacking a rock, then you're screwed unless you happen to be carrying some spare NPG+ with you.

If I were you, I'd first make sure your bike is properly uncorked and get your carbs tuning/jetting right. That should take care of most of your boiling issues even at lower speeds and you probably won't need to do anything else. Most of the other water pumper bikes will also boil over in the super slow stuff, so don't worry too much.

Is your bike stock or uncorked? What kind of jetting are you running? Do you have the stock exhaust tip, the HRC tip or a different exhaust system?

  • mousemeat

Posted May 01, 2005 - 08:40 AM

#12

The whole point of using water as a coolant is that it does overflow when it gets to a specific pressure (and therefore temperature). In boiling it is absorbing heat, which stops it from getting hotter.

The problem with boiling over is not primarily the loss of coolant. The problem is that it is an indication of increased engine temperature.

Figure out a way to reduce the temperature of your cooling system. A fan is a simple solution. So is a pressurized water container that sprays a mist of water on your rads when you push a button.

Again. The boiling is not the problem. The temperature is the problem. Increase the heat transfer from the rads at low speed.

  • ScottWR450F

Posted May 01, 2005 - 06:18 PM

#13

Thanks for all the help!!

  • gregwr450f

Posted May 02, 2005 - 12:52 AM

#14

Thanks for that mousemeat.

  • Indy_WR450

Posted May 02, 2005 - 04:29 AM

#15

Evans NPG-R and Two2Cool oil additive is what I run! Richer pilot jetting really helps as well. :naughty:

  • ncmountainman

Posted May 03, 2005 - 03:56 PM

#16

The whole point of using water as a coolant is that it does overflow when it gets to a specific pressure (and therefore temperature). In boiling it is absorbing heat, which stops it from getting hotter.

The problem with boiling over is not primarily the loss of coolant. The problem is that it is an indication of increased engine temperature.

Figure out a way to reduce the temperature of your cooling system. A fan is a simple solution. So is a pressurized water container that sprays a mist of water on your rads when you push a button.

Again. The boiling is not the problem. The temperature is the problem. Increase the heat transfer from the rads at low speed.

your nuts buddy,in boiling your losing contact with the water jacket walls. contact = heat transfer. the npg-r continues to cool where 50/50,engine ice,just plain water w/water wetter,etc. just wants to to get out of dodge. why because its still there,and at a much lower psi also. and in an emergency situation you CAN add water to npg-r,it just renders it back to a water based coolant and will boil at a lower temp. it just must be flushed again asap with the flushing agent and refilled with fresh npg-r. no harm done,straight from the mouth of a evans engineer. i don't know about you but i'd rather have a hotter bike that still cooled than one with steam pouring out of it :)

  • qadsan

Posted May 03, 2005 - 06:04 PM

#17

Why would anyone run their bike without coolant? Well, that’s about what happens for a period of time when the coolant is boiling inside your engine. Once the coolant condenses back into a liquid (when it finally cools down), it can get back to work and do its job of conducting and carrying away heat, but its not doing much of anything in vapor form just as if you were running without coolant.

Before coolant starts puking into the degas bottle or puking out the overflow tube, a blanket of tiny vapor bubbles has already formed in the hottest parts of the cooling jackets inside and around the combustion chamber in the cylinder head and this blanket grows larger and more violent as the metal temperatures increase. At this point the water based coolant has failed and all the thermal properties regarding specific heat, density, thermal conductivity, etc, have gone out the window because there’s no coolant there to conduct or carry away heat and if there is no air flowing across the radiators for convection, then the problem only gets worse. A boiling coolant results in skyrocketing metal temperatures inside the cylinder head, which leads to pre-ignition, detonation and finally engine failure if these conditions continue or accumulate long enough. Not everyone is immediately aware of when their bike starts puking out coolant and boiling means the coolant has already failed in the hottest parts of the engine. Lesser known by the rider is how often and for long how our bikes are boiling coolant inside the hottest parts of our engine without getting to the point where the coolant pukes out the overflow simply because we’ve increased our speeds, or changed the riding terrain / conditions, etc, (more air flow, or less engine loading, etc).

Let’s not lose sight of the bigger picture, which in reality are the metal temperatures under conditions when the engine is stressed or when temperatures become extreme. Evans has 1/2 the surface tension of water and 1/60th the vapor pressure in addition to being a lifetime coolant. While Evans doesn’t conduct or shed heat as well as a water based coolant, the fact is that Evans provides liquid to metal contact longer than any water based coolant made and continues working to keep metal temperatures in check long after water based coolants fail. If there’s one coolant product I trust to save my engine under adverse conditions for certain applications, it’s the Evans product because I know it will still be working when the others have failed. I’ve now used this product for years in different applications with excellent results and now I understand Ty Davis has been swearing by it for some time as well and uses it in his both his race and personal bikes. It’s not a miracle product that works perfect with all applications, but I don’t know of any coolant product that is.

  • 3boyz3dogz

Posted May 03, 2005 - 06:32 PM

#18

I had the same problem. I put a Boyesen high flow water pump on my WR, haven't boiled over since. Cost about $180.00

  • gregwr450f

Posted May 03, 2005 - 07:24 PM

#19

Good info, thanks guys.

  • mousemeat

Posted May 04, 2005 - 01:09 AM

#20

With water based coolants, you know when you are overheating your cylinder. With a higher temperature coolant, you have no idea how hot your bike is getting.

Also, the coolant losing contact with the wall is not as bad as it may seem. The latent heat of vaporization of water is huge, and boiling heat transfer has the highest thermal flux going at these temperatures. Also, the pressure is regulated by the cap, so the pressure isn't exactly skyrocketing, not that that would make much difference to the heat transfer. Pressure regulation is present only as a crude method of temperature regulation.

Looking at the website: http://www.evanscool.../html/tech1.htm , i see that the specific heat capacity of Evans is 66-71% that of water, which means that it will have less uniform temperature going through your cylinder head at points below water boiling temperate. I also see that thermal conductivity isn't mentioned, which is the most important parameter in any heat transfer analysis.

The bottom line is that evans will allow your engine to run hotter at points where water would have already boiled. But this is not where i want my engine running in the long term. I would rather run water based coolant, and increase my cooling capacity if i notice it boils.

What is the thermal conductivity of NPG?




 
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