overheating kx 500

[shum8s]

My father has an 03 kx 500. It is stone stock. Lately we have been riding on very tight, technical trails. Alot of first gear. And the beast has ran hot twice. Boiling the radiator over. Is there anything he can do to keep his bike from overheating in the slow areas. The bike is virtually new so the antifreeze is what came in it. What antifreeze we have added back is 50/50 mix. And the radiator has been totally clean both times this has happened.

 

[Yz125Rider13]

Totally clean as in what? You cleaned it out after it boiled over or did it spew out all the liquid in it?

 

[jsirvine]

Originally posted by shum8s
Lately we have been riding on very tight, technical trails. Alot of first gear. And the beast has ran hot twice.

Antifreeze isn't great at heat transfer, you might want to reduce to 20/80 and add some water wetter that does a better job of transfering heat.

 

[shum8s]

OK. I guess I should have worded this a little different. I know that a KX 500 wasnt designed to run in first gear in very tight stuff for long periods of time. Would running an a ftermarket waterpump help? If so What brand? And what brand of water wetter seems to work real well? And when I say clean. I mean the front of the radatior was free of debris.

 

[jsirvine]

Water wetter I think is a brand name, it's pink, one bottle should do several bikes. Get it at a race car store.

 

[Faded]

Redline Oils makes Water Wetter, and it is pink. This is the stuff you want and I use 1/2 bottle per bike. You should use this more as a safety net though and not a cure-all to the real problem. I had this problem with my CR on tight trails and turns out I was lean at 1/8-1/4 throttle. I'm not sure what carb comes on your KX but check the owner's manual and see what adjustment needs to be made to richen 1/4 throttle operation. It will most likely be a different needle.

 

[Faded]

Here's the Water Wetter write-up:
http://www.redlineoil.com/redlineoil/wwti.htm


To browse their site:
http://www.redlineoil.com

 

[Robcolo]

Most of the newer KX 500s I've seen run quite a bit rich on the low end - to the point of fouling plugs. IF you want a product that REALLY works, go to www.evanscooling.com Get the NPG+ formula and you'll never boil again.

 

[vetexrcr]

Shim out rad shrouds 3/4-1". I have Team Greem aluminum shims
They open the front end of the shroud bringing in more air.
Also remember when you are riding slow stuff your thighs block the radiator exit holes while sitting,so stand as much as possible or ride with your knees out to help air flow.
As everyone else said,get rid of the antifreeze
Overheating is not a new problem with the KX 500 but it not a severe fix either. I ride alot in 110 degree weather in tight stuff, you just have to be aware of it BEFORE it gets hot

 

[Kawadougie]

I have a 2003 KX-500 also but have never had a problem with overheating, even in hot, slow riding conditions. You might check your timing. As mentioned, my bike was very rich on the bottom from the factory and I'm down to a 48 pilot now. Also a vented numberplate might help increase airflow. Nothing to do with overheating, but I run with a Steahly flywheel which makes the big KX run like a giant KDX200.

 

[jsirvine]

Where did you get the flywheel?

 

[Kawadougie]

Right here!

http://www.steahlyoffroad.com/

 

[Lissa]

I used to race enduros on an 88 KX 500, pretty much the same bike as yours. Our enduros are extremely tight and I had the same problems as you do. I tried all the additives that were available then (late 80's) and nothing helped. Jetting was spot on. I tried a new radiator cap, but that didnt seem to do much. I did make a overflow bottle that would catch the coolant. I do abuse the clutch quite abit so Im sure that contributed to the overheating problem that I had. Actually that was probably the main reason. I eventually came to the conclusion that the KX 500 was not the right bike for me and my riding style and the terrain that I was riding so I switched to a 250. I do miss the 500 at times though.
Rob not Lissa

 

[bigborefan]

Originally posted by vetexrcr
Shim out rad shrouds 3/4-1". I have Team Greem aluminum shims
They open the front end of the shroud bringing in more air.
Also remember when you are riding slow stuff your thighs block the radiator exit holes while sitting,so stand as much as possible or ride with your knees out to help air flow.
As everyone else said,get rid of the antifreeze
Overheating is not a new problem with the KX 500 but it not a severe fix either. I ride alot in 110 degree weather in tight stuff, you just have to be aware of it BEFORE it gets hot

 

[bigborefan]

Where did you get the Team Green Shims