Waterwetter didn't work for me!

I rode a really tight south jersey enduro this weekend with water wetter and a 65/35 water/coolant mix. Boy, did she run HOT! I have an overflow bottle installed on my YZ 400 and it used up everything in the bottle and was down about an inch from the neck of the radiator. I ran two similar enduros previously with straight 50/50 and had no problems at all(it was about 20 degrees warmer this weekend). Changed the oil and checked for leaks, but nothing. It just burned it up, I guess?! I really need to keep this thing cool! Any tips would be greatly appreciated! Thanks! -Adam-

I had been loseing water fron my 400 for quite some time, and could not figure out why. Eventually I noticed the o-rings on the chrome looking tubes that connect the hoses to the engine were leaking when hot. Replaced o-rings, and no more leak, If you are blowing fluid out the cap, try a higher pressure cap (avalible at most auto parts stores).


Pretend it's flat and give it the gas.

I think you have something wrong...with the bike that is.

Do as mentioned earlier, and check out other potential leaks including head gasket.

And a 50/50 mix of distilled water and coolant should do just fine. Too much coolant and the flow is not as good.

And water wetter may be over-kill unless you really need it.

How many rides on the new water and coolant?

Wouldn't I have white smoke coming out of the exhaust, if it were a head gasket problem? Also, there was no trace at all of coolant in the oil. I had one trail ride and one enduro on the new coolant/waterwetter. Before that, I had about six rides on 50/50. I did notice that with the cap off and the bike running, the coolant was gurgling alot around the neck. Does that seem normal? Also, whenever I start the bike I get a strong smell of coolant. I'm coming off a long history of air-cooled bikes, so any help would be great!

I don't necessarily think you have a problem with your bike. When your workin' it hard in the sloppy tight stuff, once it gets hot the bike is gonna puke out a some coolant. I would start with a new radiator cap or possibly one with a higher pressure rating. Also, according to water wetter, it works it's best when you use just distilled water and water wetter, of course you lose your anti freeze capability but it didn't sound like you need to worry about that so long as you keep on riding. Look on the bottle and it will tell the ideal ratio. It also says it inhibits corrosion in the coolant system, so the only reason you need anti freeze is if your below freezing. I would look at the "O ring leaking" solution also. Sounds very viable to me.


99 YZ400

You're loosing coolant, you can smell coolant when you start the bike and you can see bubbles coming from the radiator when it's running (air bubbles, different than just the coolant pumping around I assume). Those are 3 bad signs, especially when you put them together. I have seen bikes with head gasget leaks not blow any visible steam out of the exhaust, especially with a minor leak. Also if it's leaking into the oil _slowly_, it can steam off before it milks up the oil.

One more thing to check. Take out your spark plug and try to determine if it's cleaner than normal. Usually coolant leaking into the cylinder will clean things up nice and shiny if enough is getting in. I don't have my 426 YET so I'm not sure how much coolant these bikes typically loose (some is usually normal), but you have enough of the symptoms of a leak to warrant taking a closer look in my opinion.

Hey Adam,

I assume you ran the Stumpjumper on Sunday. Was the 1st section tight enough for you? I trashed my rotor in the first hour but rode on anyway. The pay-off in the second half was worth it. I was there on my '99YZ with a late number so it was hot. I ,however, did not have any problems with cooling and checked my level today and still have coolant visible about 2 in. below cap. I use a 50/50 mix(distilled) with water wetter.

I know this doesn't help you but I think you should investigate further. Was your bike ticking in the tight sections or after you stopped? Could you be a running on the lean side adding to engine heat? I assume you drilled holes in the fins in front of radiators, this seemed to help me a little.

I believe that coolant(antifreeze) should still be used because of its lubrication properties. I don't know what the life of the impeller is on these bikes, but it could be a problem.

Good luck and maybe I will see you at PineHill next week.


I know these things kick out coolant every now and then, but he seems to be consuming it.

Also, I'd be interested in knowing how you converted from a YZ system to a recovery system as used on the WRs. I always thought they used different caps.

I certainly don't aim to minimize the possibility of an overheating problem, but don't overlook the nature of the 426 to run with the coolant about an inch or so below the neck of the radiator. Before I would panic about what appears to be an overheating problem, I would give the engine some time to seek it's normal coolant level. My 426 used to spit out coolant and I assumed it was overheating as well...but it settled down to that normal COLD level of about an inch below the radiator neck, as mentioned. It has kept this level for over 9 months now and I check it COLD before every ride. Don't forget about thermal expansion.

[This message has been edited by Boit (edited 04-25-2001).]

Thanks for all of the replys.

Keith, Yeah I ran the Stumpjumper and yeah it was tight! But like you said, the WFO afternoon made it all worth it! I was in first in my class when we left, but the final scores weren't up yet. I am going to richen it up a bit because I did hear some weird noises and it was cutting out in the whoops every once in a while. Like it was starving for fuel. I have the Devol rad. guards on. I know that doesn't help, but they're a necessity where I ride. I'll be at Pine Hill, but I'm a member of CJCR. So e-mail me your number and I'll look for you at my check. Good luck!

DaveJ, I did convert it with the overflow bottle from a WR, so I'm going to look into the cap situation. Thanks!

Boit, I think I'm going to take some advice from you and figure things out before I drive myself nuts. I've only ridden it four times, so I haven't figured out it's quirks or characteristics yet. I'm going on a two day riding binge this weekend just to do that!

Sirthumpalot, I figured out that the smell was from me spilling coolant when changing it last week. It went away until I spilled a little more filling it this afternoon. As for the gurgling, that checked out as normal as compared to two brand new 426's. No air bubbles, just normal flow. Hopefully, I don't have any major problems. I'll figure it out this weekend.

Thanks again for all of the help. As always, any other suggestions are always appreciated! Later! -Adam-

I have a update on my situation. YZ400Court, thanks for the advice. At first glance, I didn't see the tube at the front of the head. After further investigation, sure enough there was a leak there. Replaced the o-ring and it was fixed! Thanks!

As for the problem of it starving for fuel, I found out it was running real lean. Last weekend on a trail ride it would cut out completely intermittently. I removed the bolt at the bottom of the carb, expecting some dirt, but there was no fuel at all. I tracked it down to the one-way valve on my gas cap. Removed that and it ran better than it ever has!

Anyhow, thankgs again! Later. -Adam-

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