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.