KX250F Radiator Cap

[MadEarthWorm]

Can anyone explain this radiator cap thing with the KX250F? I saw somewhere that by going to a 1.6 cap you can prevent the coolant from overflowing when it gets too hot? What does 1.6 mean?

My bike is brand new but I'm trying to get the little fixes that are recommended out of the way.

 

[mxer842]

bychanging the radiator cap you increase the pressure in the radiator thus increasing the boiling pont of the coolant and you reduce the chance of over-heating.

 

[MadEarthWorm]

Ah, thanks for the information.

 

[490Dave]

Im sure somebody will correct me if im wrong, but i think the number refers to atmospheres. ie, 1.6 atmospheres etc. of course the number on the cap is probably set at sea level so depending on your elevation you may need to go up or down.

 

[Antman]

The only problem with going with a higher rated cap is that it increases pressure on the system. You could end up blowing a water pump seal prematurely to keep from blowing a little coolant now and then. I personally woulod add coolant as needed.

 

[High Lord Gomer]

Yeah, and 1.6 atmospheres is pretty stout. I thought my CRs used to run 1.1.

 

[truespode]

I would recommend waiting on the cap and see if you need it first.

Ivan

 

[mtneufer]

I ran 1.6 cap on my 02 crf 450 with out any problems.

 

[mxer842]

slow down guys, coolant is released once a certain pressure in the radiator is reached this isn't changed by the different cap but what is changed it that the boiling point of the coolant is raised. once that pressure is reached in the radiator then coolant is released, you will still hit that overflow in a stock cap but your coolant will have boiled a long time ago.

 

[MadEarthWorm]

HHmmnnn...I guess my thinking was that I could prevent a problem by just going with the 1.6 cap off the bat. Maybe it's not a problem at all?

 

[Brewster]

Originally posted by mxer842
slow down guys, coolant is released once a certain pressure in the radiator is reached this isn't changed by the different cap but what is changed it that the boiling point of the coolant is raised. once that pressure is reached in the radiator then coolant is released, you will still hit that overflow in a stock cap but your coolant will have boiled a long time ago.

I'm a bit confused with your statement.
Would you please explain how a radiator cap with a higher pressure relief setting DOES NOT change the pressure point at which coolant is released??
The higher pressure cap will do both, raise the temperature at which the coolant boils and raise the pressure at which the cap releases.

Ride on
Brewster

 

[High Lord Gomer]

Originally posted by MadEarthWorm
HHmmnnn...I guess my thinking was that I could prevent a problem by just going with the 1.6 cap off the bat. Maybe it's not a problem at all?

You start fixin stuff that ain't broke yet and we're gonna start callin you Ivan! :scream:

 

[MrLuckey]

It depends on the cap. Some caps will say how many PSI while others will be listed in Atmospheres. 1 Atmosphere is 14.7 psi. I would think it's safe to say yours is 1.6 atmospheres or almost 24 psi. Gomer is right, that is fairly high. I know Summers racing recommends a 19-21 psi unit for the CRF450s.

HERE

 

[BEEF706]

Yamaha Action magazine reccomended the 1.6 to cure overheating at sea level, I read it but don't know which issue it was in, some of their advice is solid, and some is voodoo, don't know about this one. :)

 

[Lonewolf]

i am probably going to buy an rm-z within the next month or so and i plan on using a cycra vented front number plate, cycra vented front fender, msr radiator guards, 1.6 radiator cap, and add redline waterwetter to the coolant to keep it running cool. i may also use the lightspeed performance air tract system to draw in more air to the radiator it is still boiling over.

 

[jboomer]

You haven't even bought the bike yet and you're already expecting the worst! I'd question my reasoning behind buying the bike if you're THAT paranoid it's going to break!

 

[Lonewolf]

i concider the mods i listed additional insurance, wouldnt it suck to be out in the middle of the woods far from the my house or truck and have the engine take a crap because it overheated? it probably wouldnt matter which bike i bought, i would probably try to get more air to the radiator for optimal performance anyway. i actually think the vented number plate, vented front fender look trick, and as far as the radiator gaurds go the stock louvers cant possibly flow as much air and protect an expensive radiator as much as the aftermarket guards do, i have had the cheap stock louvers actually ruin one of my radiators on my yz 250f.

 

[Yogurt]

Actually, I believe, and others may back me up here, stock radiator louvers do allow the best air flow for cooling. They just don't provide any real protection for the radiators other than from roost. Look at all the factory teams, they all run the stock radiator louvers, don't you think if there was a better way to get more air flow to the radiators for more cooling effeciency they'd be all over it? But most of us, don't get our bikes running that hot, so aftermarket radiator guards will still do the trick. The cheap plastic louvers do help draw more air in, rather than an open style like the Devol guards.

 

[mxer842]

carmichael does run some stermarket radiator louvers, they are carbon fiber.

 

[jboomer]

carmichael does run some stermarket radiator louvers, they are carbon fiber.

The BS flag is slowely being raised to full mast! There's not a racer on the circuit running carbon fiber louvers. I'm pretty sure they ALL run the STOCK louvers (I don't know that I've even seen aftermarket louvers).