Radiator overflow catch tank question on 2007 WR450f

I bought my 07 with half a tank in the overflow. It slowly decreased until there was nothing in it. Probably from tip-overs. (or evaporation) (the catch can is open to the atmosphere)But my radiator has always remained full, without adding. I can hear fluid transferring as it cools. (is the catch can still empty)A couple ounces wouldn't hurt, but still check it at the rad cap. I like watching the steam pour out of the CRFs at the races...(I think all bikes do this when the pressure in the closed system exceeds the pressure required to lift the cap seal off it's seat thus reducing the pressure in the system allowing the coolant to boil, rapidly evaporate, and then condense in the atmosphere.

If you run a catch can, your bike does this too. The only difference is this is all happening inside the concealed environment of the catch can.

That works perfectly fine!

I believe that if you use just enough coolant in the tank to fill the hose between the radiator and "Catch Tank" the system will perform better when the cooling system cools down and the "Siphon" begins to pull coolant back to the radiator. (That is an intelligent comment stated in such a way as your belief rather than a so called know fact and without slander, very good. )

Since water does not compress (or expand under vacuum) the radiator will fill more completely than if there is air bubbles in the hose. (now what makes you believe it won't work properly if it sucks small amounts of air followed by liquid and over again?)

You guys are funny! The mark on the catch tank means nothing.:smashpc:(now again I don't own one of these bikes but if the mark is what others think it is would it not mean the same as, say the reference mark on the dip stick of the oil pan for your car or truck. Just that, a reference mark?)

dgcars and pschiess both have a complete understanding of the system and its design intent.

Are you sure you understand pschiess? He is the one who originally asked the question that started this thread.

Thoughts and opinions can be debated if willing. If you state what you believe to be fact be prepared to be corrected if you are wrong. It's all in how you state it!

Lots of e-toughness going on in this thread. Over a simple coolant question? Brother.

Fill the overflow to the line when cold and call it good.

Darn good thing I did not ask about politics or religion here:smirk:.

I seem to be back where I started but with some very good info on both sides of the discussion. Now to decide what coolant to put in the radiators.... The manual (that I read thoroughly) calls for ethylene glycol so that is what I will use with maybe a couple OZ of water wetter for good measure.

I have a bottle of Rock Kool brand (from Europe) ethylene glycol anti freeze on the shelf so that is what I will use with maybe a couple OZ of water wetter for good measure.

I'm havng a pissin' contest tomorrow.....all welcome.

Gotta love the blogs...

Yeah, gives every douche with a pc a voice. No matter how uninformed they are about a particular bike. The catch tank system is there and marked so that it is setup correctly and it doesn't suck air. You can, however, bypass it for a YZ style system if you desire. But it's functionally different than say the DRZ system Suzuki uses so it's not apples to apples.

I mis-the original statements and stand corrected in hazing in my original post. Guess that's what happens when I read this forum first thing in the morning to wake up. My bad, I apologize.

However, my statement on weight difference stands, myself included: 99% of riders wouldn't notice 10 lbs one way or another unless told. So worrying about a soda can's amount of coolant Vera little ver the top on an already admittedly heavy bike. And yes, kx450f63, in a boiling out situation 20 oz can be the difference between overheating damage and "hey, my catch tank is empty, wonder why?" especially on a trail bike.

Just saying.

Mike

I'm havng a pissin' contest tomorrow.....all welcome.

Cool! I haven't had one of those in about 30 years... I'm in. I don't know if I can piss from here to Ireland... but I'll try. I am part Irish if that matters.

If you overfill the overflow bottle, it will just spew out what isn't needed anyway. My old 426 had a much bigger catch can so it always had some in it, with the '07 it bothered me at first when the coolant was way down in the bottle, but now I don't even think about it. As long as there is about 1/2" of coolant in the bottle it's good to go.

WR Dave

Lots of e-toughness going on in this thread. Over a simple coolant question? Brother.

Fill the overflow to the line when cold and call it good.

I agree! When metal and liquid get hot they expand and need a place to go. As the bike cools it will suck it back in.
I agree! When metal and liquid get hot they expand and need a place to go. As the bike cools it will suck it back in.
Exactly! The idea is that there's margin for error no matter hot hot or cold it gets it won't spill over or suck air.

It's not complicated at all.

I removed my whole system and have had no problems,including 100 mile desert races:ride:

You won't need a tank for desert racing. Where you will lose coolant is while going very slow where there is not much air flow to the rads. Anyone riding tight singletrack should hang onto their tank.

Geezz

Geezz
Agreed. I'm personally shocked how many folks have no idea what an overflow tank actually does and why but their way is gospel.

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