MNNTHBX

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Here's a cheap solution to controlling you cooling system. Replace the junk radiator cap with this high quality 1.6 bar cap. Reduces boil based cavitation and resists puking.

$19 MNNTHBX - Enter

 

reenmachine

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I definitely recommend this! I made the switch to a high-quality 1.6 bar cap a few months ago and it cured all my cooling woes. No more puking and less fan.
 

Old3

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The stocker is low grade junk, i agree. Raising the pressure will increase the boiling point, which enhances the ability to remove heat. Once its boiling it just keeps getting hotter.

My hopes are this cap will help hold off an overheating of the cylinder head (warping same possible, or making it worse anyway as its probabl not true to begin with) and the eventual destruction of the cylinder head gasket.

Its a no brainer mod, the pressure increspase isnt massive, its well within normal range for motorcycle engines. If this pressure increase causes a hose to pop, it was going to pop anyway. Keeping the coolant from becoming vapor is key!
 

Treachery

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Okay, at the moment, my physics ed-u-ma-cation is eluding me: Increasing the pressure will increase the boiling point. But that happens independent of operating temperature, yes? So, IIRC, non-boiling liquid is better able to absorb heat from the surfaces it's in contact with (hot engine). Am I thinking straight?
 

Old3

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Ummmm, not sure what you are asking about regarding operating temps?

If it boils, the vapors in the coolant (bubbles ) do not transfer heat efficently so you get hot spots, more boiling coolant, more hot spots and your overheating cause it cant draw away heat that is constantly produced.

Then stuff starts to warp or melt.... Just get the cap! Lol!
 

reenmachine

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Okay, at the moment, my physics ed-u-ma-cation is eluding me: Increasing the pressure will increase the boiling point. But that happens independent of operating temperature, yes? So, IIRC, non-boiling liquid is better able to absorb heat from the surfaces it's in contact with (hot engine). Am I thinking straight?

Correct. Once it's boiling you're screwed as there's not uniform contact between the coolant and the surfaces it's trying to extract heat from due to the vapor bubbles.

There appears to be such variation in the pressure capacity of the OEM cap that the boiling temp can be significantly below what you need it to be. Mine and I think one other forum member's were extreme cases where we'd boil over and puke all over the place on pretty much every ride. Switching to a high quality 1.6 bar cap completely erased these cooling problems for me and my cooling system is super stable now, street and track.

That being said, simply switching the OEM cap out for a 1.4 bar cap (OEM spec pressure) may have solved my problems as well, but there's no downside to bumping it up to 1.6 bar and gaining that extra bit of margin. You're nowhere near approaching a pressure that will cause problems unless there's some other defect-based weakness in the system.
 

Fasteddy

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Yes, what they are saying...
Even if it is not boiling over to the point of dumping to the tank / overflow and everything seems fine, at lower pressures cavitation (bubbling) can occur in the water jacket especially on the head. Raising the pressure / boiling point can prevent this. Mine has never boiled over but the concept of having a higher boiling point and more efficient cooling system has a new cap being shipped....
 

simpletty

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So in essence with this rad cap we are raising the boiling point roughly 9 degrees higher. I think its a no brainer. Adding water wetter or Evans’ NPG coolant will increase the boiling point even higher.
 

Treachery

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So, a month or so out, who's running these, and any problems with the system accepting the higher pressure?
 
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