coolant loss while sitting

[mechanos]

My sons 200 appears to be loosing coolant as it sits. He took a spill this weekend and bent the radiator/ripped the lower radiator hose. I was able to cut the hose and slip it back on (radiator is bent back). I re-filled it and we rode all day with no apherent loss, but the next morning it was low. Did the same thing the next day with no loss. We trailered the bikes home (8 hours from the UP to central Illinois) and the exp. tank was nearly empty. Isn't leaking anywhere that I can see and the oil is still red. Any ideas? no loss prior to the crash.

 

[craig_enid]

I had a lower hose that would drip only when running and very hot. Never saw any leak, just had to re-fill the overflow tank every ride. Finally noticed the drip while on the trail. Tracked to the hose/clamp and tightened. No more chronic loss.
Good luck.

 

[Patman]

How do you know it's not lost while riding? The coolant expands under heat which is why you have an expansion tank.

 

[julien_d]

Also, if you're worrying about the overflow tank being empty, don't. The overflow tank will almost always be empty after a ride, or when the bike cools and that coolant gets sucked back into the rads.

 

[domino dave]

Quote: Coolant overflow tank always empty
The plastic coolant overflow tank under the left sidecover on pre-'95 watercooled bikes will tend to lose its fluid no matter how often you top it up. Why this happens is a bit of a mystery. Some say that it gets sloshed out the small overflow tube. Personally I have wondered if it sort of just gradually vapourises off because of the incredible aeration and agitation that it gets from engine vibes and all the violent heaving around when riding. Don't fight this problem in vain, just run the overflow tank empty and keep an eye on the radiator level, which will stay pretty constant without the benefit of any overflow reservoir fluid.
Some KDX owners remove the overflow tank, but it doesn't hurt to leave it in place to catch and condense any vapour and allow the radiator to suck it back in again later.
Update 7/03: I recently followed a suggestion posted by someone on the KDX forum and bent the overflow tank outlet nozzle upwards slightly to prevent liquid sloshing out. It worked! I was amazed to find the overflow tank full after a very rough day's ride. This is the first time it has retained its fluid. Here's what to do: If you remove your left sidecover and seat, you'll notice that the overflow tank's outlet or breather tube is positioned at the top and sits horizontally. You need to bend this upwards at an angle so that any liquid that slops into it runs back down to the tank. I used an electric heat gun on the plastic tank at the nozzle junction. The heat softens things enough to let you bend the nozzle upwards. Be careful not to pinch off the inside diameter. You have to clear the subframe tubes somehow too. I elected to point the nozzle outwards as well as upwards, and re-route my breather tube so that it now runs around the outside of the frame (see pic). This seems to work fine and just clears the seat and sidecover. That's it.
See this thread for more. To reportedly cure boilover once and for all, use the (expensive) waterless coolant made by Evans Cooling.: Quote
I took this from this guy's site.
[\
url]http://www.craig.copperleife.com/bikes/kdx/index.htm[/url]
It is true for me .... Dave

 

[domino dave]

OOOPs .... Here is the link .... http://www.craig.copperleife.com/bikes/kdx/index.htm

 

[Dirtdame]

You never want your tank to be completely empty. If you leave it empty, you might as well remove it. There should always be some coolant in the plastic tank, so when the radiators heat up enough to cause the pressure to "blow" the cap and back coolant into the tank, there is some cool coolant in the tank to mix with the boiling hot coolant coming in. Some bikes (not a lot) that have been run with dry tanks end up getting the plastic melted and a hole in the tank when hot coolant backs into the empty tank, and the riders have gotten hot coolant on their legs. :ohmy:

 

[mechanos]

My son has had the bike for a year now, and it has never lost coolant until this weekend, when he bent the radiator and poked a hole in the hose right at the bottom inlet. I repaired the hose and refilled. Tank was full at start of ride, and I checked it periodically throughout the day. The next morning it was down nearly 1/3. Same thing the next day.

 

[dirt bike dave]

I'm convinced much of the coolant in the overflow tank sloshes out when you are bouncing along on rough terrain.


If you filled the overflow tank full at the start of the ride, much of it got pushed out when the coolant in the motor expanded as the bike got to normal operating temp, and the rest just leaked out as he was bouncing along the trail.

FWIW, most bikes don't have any overflow tank, and they get along fine.

 

[julien_d]

If the rads are more than a few ounces low, you can worry. If it's just the overflow tank, who cares? The overflow tank definitely sloshes out. Mine will always be empty after a ride if I fill it beforehand.

 

[domino dave]

If the rads are more than a few ounces low, you can worry. If it's just the overflow tank, who cares? The overflow tank definitely sloshes out. Mine will always be empty after a ride if I fill it beforehand.

I agree. It was probably doing the same thing before your son wrecked?

 

[mechanos]

Something must have happened for it to not leak/slosh out (1 full year) then after the crash it leaks, but undetectably...any agreement on this?

 

[domino dave]

Pressure test ??