Keeping a YZ450 cool for single track


23 replies to this topic
  • 700rScott

Posted December 09, 2015 - 08:14 AM

#1

This past year I hit 250 degrees a few times in the tight stuff. I've learned to keep the rpms up a little more to keep the pump going a little faster but the 2 smoke guys I ride with like to do some slow stuff. I have a wr coolant tank to catch any boil over if it did get too hot but I'd like to try to keep the temps as low as possible. I look at doing a Boyesen super cooler water pump, Ebay over sized rads since my one has a nick in the one line so I'm worried it would crack if dropped and then adding engine ice. Do you guys think with doing that much I'll be much better off with keeping the temps down or would I still be looking at adding a fan or two?

 

These are the two rads that I'm guessing are from china but area here so there's no 1 or 2 month wait for shipping.

http://www.ebay.com/...=STRK:MEBIDX:IT

or these ones that claim up to 30-35% better cooling

http://www.ebay.com/...=STRK:MEBIDX:IT

 

Thanks


Edited by 700rScott, December 09, 2015 - 08:16 AM.


  • Monk

Posted December 09, 2015 - 08:26 AM

#2

-Supercooler
-Silicon Rad Hoses
-Engine Ice
-Higher Pressure Rad Cap
-Lower gearing
-Larger radiators

All these will help and if combined will make for a near bullet proof system. Riding habits also make a huge difference. Ultimately buying a bike more suited for the terrain you ride is something you should also consider...

  • 700rScott

Posted December 09, 2015 - 08:49 AM

#3

Thanks and I'd love to get a 300 but that plan has been pushed back.



  • Krannie McKranface

Posted December 09, 2015 - 09:27 AM

#4

GPI on ebay makes and sells good chinese radiators and hoses. Both YZ and WR sizes.

The hoses will not make a temp change, but they won't split or crack or collapse either

This will drop your temp about 15 degrees, so it can still boil over in slow going.

The ONLY thing that will prevent boil over is a fan, or a higher pressure cap (which is just raising the boiling point)

 

I went with the GPI WR radiators and hoses, and a 1.8 cap, and I can do a 10 min clutch fan-it-to-death hill and not boil over.

 

It will not boil over if sitting idleing for 15 minutes.



  • GHILL28

Posted December 09, 2015 - 09:36 AM

#5

Engine Ice and high pressure cap and I've only ever gotten mine making noise once, and that was after some rather unusual abuse.  Most extended 1st-2nd gear sections it won't make a peep.



  • 700rScott

Posted December 09, 2015 - 09:50 AM

#6

GPI on ebay makes and sells good chinese radiators and hoses. Both YZ and WR sizes.

The hoses will not make a temp change, but they won't split or crack or collapse either

This will drop your temp about 15 degrees, so it can still boil over in slow going.

The ONLY thing that will prevent boil over is a fan, or a higher pressure cap (which is just raising the boiling point)

 

I went with the GPI WR radiators and hoses, and a 1.8 cap, and I can do a 10 min clutch fan-it-to-death hill and not boil over.

 

It will not boil over if sitting idleing for 15 minutes.

Thanks for the info and I'll go with them since I have someone having good luck with them, if I drop 15 degrees I'll be happy with that. what is the difference between the WR and YZ rads?



  • grayracer513

Posted December 09, 2015 - 10:03 AM

#7

Whether all that works or not will depend on a lot of intangibles/unknowables.  Usually, the listed fixes will add up to enough, especially if you focus on keeping the bike in motion.

 

Ultimately, though, since the real problem is lack of air flow across the radiators, the real fix is a fan.



  • 700rScott

Posted December 09, 2015 - 10:06 AM

#8

Engine Ice and high pressure cap and I've only ever gotten mine making noise once, and that was after some rather unusual abuse.  Most extended 1st-2nd gear sections it won't make a peep.

luckliy my longest 1st/2nd gear section is about a half a mile at the most but it could be up and down.



  • 700rScott

Posted December 09, 2015 - 10:11 AM

#9

Whether all that works or not will depend on a lot of intangibles/unknowables.  Usually, the listed fixes will add up to enough, especially if you focus on keeping the bike in motion.

 

Ultimately, though, since the real problem is lack of air flow across the radiators, the real fix is a fan.

yeah I understand if I'm just idling there a bunch of times I'm done but if I can stay moving I have a decent chance of keeping it at a normal temp. I left the supermoto part out if I'm sitting in traffic but I'm hoping for the single track stuff to maybe keep it below 250 so I don't have to let her rest to cool down. This year was the 2nd year on a bike so I'm slowly learning how to pick the pace up in the tight stuff and hopefully next year will be even better. Also i haven't tried the HD stator again since the last time I had issues but that wasn't my problem so if I can get the HD stator to work I'll have to figure out a way to add the fan but encase the electrical stuff fails I'd like the fool proof mechanical way to get the heat away and out.


Edited by 700rScott, December 09, 2015 - 10:15 AM.


  • GHILL28

Posted December 09, 2015 - 03:27 PM

#10

luckliy my longest 1st/2nd gear section is about a half a mile at the most but it could be up and down.

 

For reference, the place where it began to boil was on a slippery trail that went up 1 or 2k feet and went over a few dozen slippery logs and loose steep climbs.  It wasn't so much a "trail" as it was "hacking my way through the foggy wilderness hoping I didn't get lost".  Short of that level of abuse it's been silent.



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  • stevethe

Posted December 09, 2015 - 03:44 PM

#11

yeah I understand if I'm just idling there a bunch of times I'm done but if I can stay moving I have a decent chance of keeping it at a normal temp. I left the supermoto part out if I'm sitting in traffic but I'm hoping for the single track stuff to maybe keep it below 250 so I don't have to let her rest to cool down. This year was the 2nd year on a bike so I'm slowly learning how to pick the pace up in the tight stuff and hopefully next year will be even better. Also i haven't tried the HD stator again since the last time I had issues but that wasn't my problem so if I can get the HD stator to work I'll have to figure out a way to add the fan but encase the electrical stuff fails I'd like the fool proof mechanical way to get the heat away and out.


As long as there is fluid in the radiators you have nothing to worry about. We do some of the worst hill climbing and technical riding imaginable. All or almost every rider is using straight antifreeze which makes the bike run even hotter. My Supermoto runs straight as well. No issues whatsoever.
The big problem is when you loose your fluid you will fry your top end. So short of boil over just ride it.

  • 700rScott

Posted December 10, 2015 - 08:39 AM

#12

As long as there is fluid in the radiators you have nothing to worry about. We do some of the worst hill climbing and technical riding imaginable. All or almost every rider is using straight antifreeze which makes the bike run even hotter. My Supermoto runs straight as well. No issues whatsoever.
The big problem is when you loose your fluid you will fry your top end. So short of boil over just ride it.

Ok thanks and I have the catch can on it to be able to suck it back in when she cools down cause my one buddy was loosing a little from the expansion. Then when it got cooler it wouldn't have anything to suck back in so it was overheating bad.



  • grayracer513

Posted December 10, 2015 - 09:52 AM

#13

Ok thanks and I have the catch can on it to be able to suck it back in when she cools down cause my one buddy was loosing a little from the expansion. Then when it got cooler it wouldn't have anything to suck back in so it was overheating bad.

 

Normal expansion and contraction of the coolant volume should not result in a net loss beyond the amount that is pushed out as the coolant reaches it's max liquid temperature.  If it doesn't boil, you won't loose coolant unless the system, including the cap, leaks.  Basically, if you filled the radiators, what you should find at the end of cooling down for the day is coolant standing just at or slightly over the tops of the core tubes, and you should be able to ride the next day without filling and have no further loss.



  • stevethe

Posted December 10, 2015 - 12:13 PM

#14

Grayracer is right.

Also don't be confused with just having a catch tank. You can still boil out too much fluid and cause damage to a motor. So the signs are if its boiling. You can first do what the other posts are saying to do. If all else fails and you don't want to bother with fans more coolant added works.

  • 700rScott

Posted December 10, 2015 - 01:25 PM

#15

The catch can is just there to keep it topped off and that's what I was hoping with the bigger rads to give it more volume to work with and try to allow as much heat to get out as possible.



  • Wiz636

Posted December 14, 2015 - 09:16 PM

#16

I've learned to keep the rpms up a little more to keep the pump going a little faster

I wouldn't do that. You are creating more heat by revving the motor than the radiators will be able to dissipate without a fan.

 

I make my own coolant out of 80% water, 20% ethyl glycol coolant, and a little bit of a surfactant (Redline Water Wetter) to help the mixture transfer heat from the water jacket wall better. It works as good as, if not better than the ridiculously expensive Engine Ice.



  • GHILL28

Posted December 14, 2015 - 10:07 PM

#17

I wouldn't do that. You are creating more heat by revving the motor than the radiators will be able to dissipate without a fan.

 

I make my own coolant out of 80% water, 20% ethyl glycol coolant, and a little bit of a surfactant (Redline Water Wetter) to help the mixture transfer heat from the water jacket wall better. It works as good as, if not better than the ridiculously expensive Engine Ice.

 

The $10 or whatever it is the Engine Ice costs also is the price of not having to do some bathtub methlab-level shit to get decent coolant...



  • 700rScott

Posted December 15, 2015 - 09:29 AM

#18

I wouldn't do that. You are creating more heat by revving the motor than the radiators will be able to dissipate without a fan.

 

I make my own coolant out of 80% water, 20% ethyl glycol coolant, and a little bit of a surfactant (Redline Water Wetter) to help the mixture transfer heat from the water jacket wall better. It works as good as, if not better than the ridiculously expensive Engine Ice.

A motor is an air pump so the more air you get the cooler it can run if the cooling system is working properly on liquid cooled motors. The higher the rpms get the more coolant you can pump through the system to try to get the heat out of the motor.

 

I solved this problem by selling the bike so thank you to the guys helping me out with the question. I was looking at the money I can get for the bike and what it would cost to do a few things so I figured it would be better to put the money into something a little newer and more the style I'm riding right now.



  • grayracer513

Posted December 15, 2015 - 09:53 AM

#19

A motor is an air pump so the more air you get the cooler it can run if the cooling system is working properly on liquid cooled motors. The higher the rpms get the more coolant you can pump through the system to try to get the heat out of the motor.

 

The first sentence contains two unrelated statements and draws a conclusion not linked to either one by logic.  The engine is an air pump, on one level anyway, but that fact is totally unrelated to the cooling system, whether air or liquid cooled.  None of the air "pumped" by the engine goes anywhere near the cooling system, and all of it ends up hotter for it.   In fact, the more air that runs through the combustion chamber, the hotter the engine will be.

 

Moving coolant rapidly through the system does nothing beneficial if there is no corresponding increase in convective cooling at the radiators ("radiators" don't actually radiate heat well at all, they rely on convection).  Since there is no air moving over a stationary motorcycle, absent a fan, removing more heat from the engine to the coolant does nothing but heat the coolant, since the heat has nowhere else to go.  Raising the RPM simply increases the rate at which heat is created and how fast the coolant receives heat from the engine. Take two identical bikes at a standstill, the one with the higher idle speed will overheat first. 



  • OUTERLIMITS

Posted December 15, 2015 - 04:14 PM

#20

The first sentence contains two unrelated statements and draws a conclusion not linked to either one by logic.  The engine is an air pump, on one level anyway, but that fact is totally unrelated to the cooling system, whether air or liquid cooled.  None of the air "pumped" by the engine goes anywhere near the cooling system, and all of it ends up hotter for it.   In fact, the more air that runs through the combustion chamber, the hotter the engine will be.

 

Moving coolant rapidly through the system does nothing beneficial if there is no corresponding increase in convective cooling at the radiators ("radiators" don't actually radiate heat well at all, they rely on convection).  Since there is no air moving over a stationary motorcycle, absent a fan, removing more heat from the engine to the coolant does nothing but heat the coolant, since the heat has nowhere else to go.  Raising the RPM simply increases the rate at which heat is created and how fast the coolant receives heat from the engine. Take two identical bikes at a standstill, the one with the higher idle speed will overheat first. 

Your last paragraph.....this is why sometimes I wonder how/if those aftermarket water pumps are always able to back up their claims.  I understand the pumps with more or bigger blades on them can move more coolant, but can it not also move more coolant through and out of the radiator before the radiator has the chance to do it's thing?  Along the same lines, the coolant lines from my and most bikes goes from the head/cylinder to the top of one radiator where there is a crossover tube to the other radiator and then the bottom of both radiators plumb back to the pump.  It would probably be a hassle due to the extra plumbing, but seems like it would be more efficient if it went from the head/cylinder to the top of one radiator with no crossover tube then to the bottom of that radiator, then to the top of the other radiator and then out the bottom of that one to the pump.  Maybe it wouldn't make enough difference.







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