overheating

[KelvinKDX]

Several years ago i had trouble with my kdx200 (EG225) overheating - i switched to the Evans coolant and have not had a problem since.

 

[bake]

Mine just overheated yesterday on a long slow technical climb, I stoped to let it cool then took the lead and got some air past the rad. It seemed to help but I can't always go fast in a section.

 

[TriniG]

I had overheating probs too. I ride in a hot tropical environment. I put Wetter Water and installed two computer fans on the left radiator that are wired into my high beam light so that at a glance I can see that they are on. On slow rides I just switch to high beam, hey presto, fans on. Haven't boiled over since.
1998 KDX220 (Japan Model)

 

[Old Man Time]

Not the air mix

Posted by OLD MAN TIME:

After reading this thread I hope I don't run into the same problems you have. It seems the only way I have been able to give my bike some bottom end pull is to lean the slow jet circuit. I am already down to #42 Slow Jet with the needle on the #1 clip and a #145 main. And it acts like it would do better with a #40 slow jet, it still has a hesitation down low. Airbox lid removed, Boyseen power reeds and FMF torque desert pipe. The bike still hesitates a little down low but nothing like it did when I was rich in the idle circuit. Then it simply did not have any low end nada (not an exageration).


Did you adjust the air mixture screw???Try turning out and in till you get a response you like. Sounds like fine tuning it to me :nod:

The more I turned the air mix out the worse the low end got. When I tried a #45 slow jet the low end was bad and air adjustment screw had little to no effect.

The bike is 4 weeks old and it has never had a low end power. You were either on the pipe or killing the engine on any kind of steep hill. So naturally you would have to work the clutch so much in the tight steep stuff that the bike had no choice but to overheat.

Before our ride Saturday 8/20/05 we pulled the power valve rod cover. From the factory they never torqued the nut on the end of the power rod. In other words the power valve was not working. I had tremendous top end but zero low end. The nut was not even finger tight. Had I gone on that ride with out checking the power valve Kawasaki would have been replacing a clutch and who knows what else when the rod dropped down onto the clutch.

We adjusted the power valve timing and tightened the nut and miracle of miracles I now have decent low end. So we set out thinking all was well and the bike would be able to handle anything we threw at it. In the tight steep technical stuff it still over heats.

What angers me the most is the fact that the engine may not of had this over heating problem if it would not have been overheated the first. And that was Kawasakis fault due to the power valve not working forcing the clutch abuse which super heated the engine oil.

So now I have to deal with the same problem that many are having on here. KDX220's simply have rotton cooling systems for that displacement of engine. Obviously the 200's are running right on the edge of the cooling systems abilities.

First I am going to try Canadian Daves suggestion and try to jet the bike cooler. Now that I have low end compression (which equals power) I will go back to the #45 pilot and see if it helps cooling. If that does not work I may try Evans or take the bike back to Kawasaki since it is still under warrantee and make them deal with it.

Keep in mind that it will climb hills and never over heat as long as you are able to use second gear and keep the speed up. But in the nasty steep Technical areas it over heats really fast.

Evans may void my warrantee so I have make sure before I use it. Evan cannot even boil until about 350+ degrees which means you could run your bike at 340 degrees all day and not know it. But would that be detrimental to the bike? I'm not sure.

 

[BRush]

Also does not Evans mask a possibly more serious problem? When a bike overheats its telling you something ain't right. Evens does not boil over because it must reach a much higher temp to boil in the first place. Your bike may be running hotter than it should and you would never know.

Not necessarily. Any bike running a water / anti-freeze mix can boil the coolant. Hot weather + low speeds + an extended session of wringing the crap out of the motor in a technical section where the bike is not moving or moving slowly will usually do it. Water wetter + distilled water is one way to go. This has the most heat capacity - meaning a given quantity of heat energy will raise the temp of a given quantity of coolant the least. Your engine will be the coolest with this mixture right up until it boils. That's the rub, because water has the lowest boiling point. Water wetter& just water works pretty well. I ran this mix in my KDX for a long time and it boiled less than my 50/50 ethylene glycol/water mix. But it did still boil occasionally under severe abuse in hot weather. Typical anti-freeze mixes ( 50/50 ethylene glycol/water) or something like Engine Ice ( propylene glycol/ deionized water mix) have less heat capacity, but higher boiling points. Engine ice strikes a decent balance and I've run this in my KTM enduro bike for two seasons, but at a recent hot weather enduro there was a series of long hard uphills followed by a highly technical slow speed section. The engine ice boiled over with such force that I lost about half my coolant in just a couple of minutes. If you are trail riding, you can just take a break and let things cool down (assuming you have a catch bottle like the KDX - my KTM does not). That's a bad option in an enduro. That was the last straw for me so I've just recently switched to Evans NPG-R coolant which has no water in it and a phenomenally high boiling point. The tradeoff of course, is that your engine runs hotter with this stuff - but not as hot as when you boil out half your water-based coolant and have to finish the last 15 miles on a bike running a lot less coolant that it was designed for. The enduro yesterday was the first Evans try out. It had a lot of long uphills and it was hot. No boil over, so far so good. Engine seems to run ok.

 

[John Harris]

Thumper Racing markets an aftermarket coolant overflow bottle for KTM that helps with part of the problem. I only ride KDX but I understand from KTM riders that it works well and we have plenty of heat lately! Cheers John Harris

 

[BRYDEN1]

My two season experience with EVANS has only been positive. The one thing I have noticed is that I never feel the heat of the engine on my legs anymore. Before the evans, I always new when she was close to boiling because I could feel it. With the Evans, I have never felt it get hot yet. This isn't very scientific, but It's proof enough for me. IMHO the EVANS is the way to go. It solved all my overheating problems.
As for the idea that the high boiling point could mask other problems, well yes, that is true. No product is Idiot proof, some may only be more idiot resistant than others.

 

[yotamotive]

Alternative to Evans?

I too had a 2003 220 that overheated during slow moving high output situations. I looked into EVANS NPG and think I may have found a cheaper easier to acquire product. Per EVANS web site their product is 99% propylene glycol and 1% additives with a boiling point of 369 degrees Fahrenheit. Sierra Antifreeze is (per it's MSDS, material saftey data sheet) 96% propylene glycol, 3% water, and 1% additives with a boiling point of 365 degrees Fahrenheit. You can buy Sierra at your local autoparts store for less than ten bucks. The only difference being the 3% water resulting in the 4 degree boiling point difference which seems to me to be negligible compared to conventional 50/50 water/ethylene glycol with a much lower boiling point (264 degrees F). Boilover is a result of cylinder wall temperatures reaching the boiling point of the coolant. Once boiling begins a small pocked of air is created on the backside of the cylinder wall where the coolant resides. The lack of coolant in this area causes even more heat to be created because the coolant can no longer remove the heat from that spot due to lack of contact. So this small problem begins to create a larger chain reaction finally resulting in the boilover we all know too well. The idea behind products like EVANS and Sierra is by using only propylene glycol it increase the boiling temperature thus eliminating boilovers. An engine that runs hotter is not necessarily a bad thing, temperature differences (like during a boilover: air pockets-hot, coolant-cold) cause engine damage. Most important is that an engine remains at a constant (not necessarily low) temperature throughout, within reason of course. Thats the way I understand it at least. I currently use Sierra and it works great, no more boilovers. Just my .02. Hope I have helped a little..............

 

[COMBEN]

have you tried jet washing the radiators from the reverse side, most people will jet wash from the front...try from the back of the back forwards...I do this after every ride and you will be amazed at the crap that comes out of the rad's.