WR coolant recovery system

Has anyone removed the coolant recovery system from their WR400? Do you need a radiator cap from a YZ? Any overheating problems?


Ive had no problems. Rode last weekend in 105 degrees at Hot Springs, AR enduro. No coolant loss as long as you have the resivor on.


Darin from Missouri - 1999 WR 400F

milkman. That is what I was meant, removing the reservoir, (coolant tank), from the rear frame and running it like a YZ. Has anyone tried this? Is there much coolant loss?


I ride my YZ in 2 to 3 hour off road events in the southwestern desert and mountains. It is often above 100 degrees and in some of the more mountainous terrain the speeds are slow. Perfect conditions for my bike to spit out all its coolant.

But this has never happened. After a few long rides like this I have never added more than a few cups of coolant, and I may just be overfilling and losing the same amount every time (I fill to about an inch below the cap).

My YZ does have an extra row in its radiator compared to 98/99s WRs & YZs('00 WRs I'm not sure), but it also has 26 more cc.s. Maybe the YZ has a higher pressure cap due to lack of recovery tank?

But if not I wouldn't hesitate to remove the recovery bottle on your WR.

I removed mine and haven't had any problem losing coolant. I think if you're going to be in a situation where you are sitting idling, not moving for more than a couple minutes you'd want the resivor.


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What do you believe the benefit of removing the recovery bottle? Weight? I can't imaging it would make a whole lot of difference.

Thanks guy's. I think I will try it. Bryan, it's not so much the weight of the bottle but the weight of the fluid it holds. That along with a few of the other extras that the WR has adds up to a significant amount of weight. I'm coming off a CR250 to the WR and the WR feels taller and heavier. I'm a vertically challenged spode and need all the help I can get.

Thanks again.


I took my bottle off my bike and have had no problems. I played around with different caps, but the stock one works fine under most conditions. It is pretty warm where I ride and I seldom loose any coolant. If it was a mudder, I would consider putting the bottle back.

The main reason I lost mine was to get rid of those hoses running all over the bike. It makes it easier to get the subframe on and off, looks much cleaner - less things to go wrong.

My $0.02

By the way, the YZ cap is the same pressure rating as he WR (1.6). Try Stant (auto parts) if you want a higher pressure cap.

I've had my WR boil over twice. Once in Moab on a very hot day and once on a 100 degree day at Rampart Range in CO.

Both times it boiled over into the reservoir and then spewed out of the reservoir onto the ground through the drain tube.

It was so hot that I could sqeeze the reservoir's sides together like it was paper.

Then when it cooled off, it drew back what was left in the reservoir like it was supposed to.

My point is this, I'm glad I had the reservoir. I may not need it all the time but it sure came in handy when I did.

I guess it depends if you are really concerned about weight loss. Do you race? I would advise leaving it on if you are just riding trails for recreation.


Dougie, '99 WR400 with a lot of dumb, stupid, here take my money, I have to have them but they don't make me a better rider extra mods.

(Except the dampner :))

On several occasions on long steep slow climbs I have severly exercised my coolant recovery system. My WR would sound like its making coffie with the fluid boiling in the resevoir bottle. But as it cooled down the fluid would go back in the radiator.

Those who I have taking on trail rides with WR's (Scott H.) and YZ's (Steve Y.) also experience these conditions. In Scotts case the coolant recover system worked fine and fluid was recoverd in Steves case he lost about a third of his coolant.

I took mine off for one ride and put it back on after loosing coolant. The whole recovery system is less than 5oz and the fluid if set between the marks on the recovery tank maybe another 4oz. which is cheep insurance. My coolant system has been well exercised and works great its staying on the bike.

My 2 cents worth


Thanks again for the info. Yes, I will be racing the bike. local MX and GP's. Plan on putting the system back on for trail riding.

Hick and Heywood, my stock cap is a 1.1. I will try a 1.6 cap.

Thanks again for all the feedback.


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