different radiator caps

10 replies to this topic
  • Arizo

Posted October 09, 2014 - 12:05 PM


I have been looking around and saw high pressure caps are better against boiling coolant.

I have a yz426f.


Is there any difference in 1.4 bar, 1.6 bar, 1.8 bar and 2.1bar?

Is the boiling point significantly lower with a 2.1 bar cap then a 1.6 bar cap for example?


Here i saw moose racing has those http://www.bikebandi...or-cap?m=145868



  • woods guy

Posted October 09, 2014 - 02:22 PM


A higher pressure cap will increase the boiling point. If you know the type and % glycol in your cooling system then you can reference a chart to see the boiling point

  • Arizo

Posted October 09, 2014 - 02:37 PM


Ok. So a 2.1 is always better then a 1.6? Or does a higher bar then 1.6 have negative effects on something?

  • grayracer513

Posted October 09, 2014 - 03:25 PM


Stock is 1.1 bar.  That's 16 PSI that the cap will maintain in the system, and that's what everything in the system was designed around.  1.6 bar is 23 PSI, and 2.1 bar is a smidge over 30 PSI.   That's a lot of pressure on hoses and clamps and radiators and stuff.

  • Arizo

Posted October 09, 2014 - 03:29 PM


If you had the choise gray for what would you go? Hoses and clamps should not fail under such pressure i think, i can be wrong.

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  • Arizo

Posted October 10, 2014 - 05:58 AM


Found an answer and it looks like it would not hurt.

  • grayracer513

Posted October 10, 2014 - 12:25 PM


Where did they say it wasn't dangerous?

  • Arizo

Posted October 10, 2014 - 01:51 PM


They said they used it for there test bikes. You would not use it for your bike?

  • grayracer513

Posted October 10, 2014 - 02:52 PM


No, I wouldn't for exactly the reason they listed as a squawk: 



Unless he is frustrated by overheating issues, there is no reason ... to switch to a high-pressure radiator cap.


I have no such problem. 


However, if I did, I might go to a 1.6, raising the boiling point to 300 ℉.  Never the 2.1, though. 

  • Arizo

Posted October 11, 2014 - 12:51 AM


Ok thx :-) ill get a 1.6 then.

  • 72degrees

Posted October 11, 2014 - 03:33 AM


Hmm, I hadn't thought of trying that. The tuned 04 speed hill climber  has a tendency to get hot and bothered if kept waiting on the start line for too long on a hot day. So much so, that I've rigged up a catch bottle to keep the marshals happy. We have to run plain water in the system, but they still don't take kindly to anything wet being dropped on the track.

Edited by 72degrees, October 11, 2014 - 03:33 AM.

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