Thinking about fans for my 07 yz450


16 replies to this topic
  • 559stan

Posted April 18, 2012 - 06:05 PM

#1

Has anyone installed radiator fans on there yz? How about header tape on the first foot of pipe?

  • Octanee

Posted April 18, 2012 - 07:05 PM

#2

Has anyone installed radiator fans on there yz? How about header tape on the first foot of pipe?


fans, well i slightly do question on the fans just in the sense of, would it impede cooling while actually going faster?, but i also assume something like some computer fans to use? 120 or 140mm?, and the wrap stuff for the header you can do but i would think the stuff might not like water/dirt and may fall apart after some time?

  • cereal killer

Posted April 21, 2012 - 05:44 AM

#3

Other people have used computer fans before, but I think on your bike the trick would be powering it. You would probably have to look into using a battery that you recharge before every ride. I currently use a 12-volt nmih I soldered together from the cells from an RC-car battery to power my LED headlight. I can take some pics for you to check out if that approach might interest you.

I'm curious if anyone wraps the beginning of the header too. I've heard of it being used on a KLR650 and ending up destroying the cylinder and header from excessive heat, so I wouldn't want to be the guinea pig.

  • grayracer513

Posted April 21, 2012 - 08:15 AM

#4

Wrapping the header in heat tape has one identifiable benefit: It keeps you from burning your leg on it. Other than that, anything it "does" is purely imaginary. With regard to the cooling system, the amount of heat transferred to the radiator by convention from a bare header is miniscule even in still air, and the least bit of air movement over the pipe essentially eliminates that.

The only real benefit of it is in applications where the engine is in a closed compartment where keeping the heat from the headers away from the intake system may be of value. Otherwise it has no performance benefit of any kind.

Some steel headers have been cosmetically damaged by header wrap retaining excessive heat (particularly chrome plated ones) but apart from that, it won't hurt the engine.

  • LILBIT

Posted April 22, 2012 - 11:35 AM

#5

grayracer-My KTMs header was within a 3/8 " of the radiator. After wraping from the head to just past the rads my fan ran 1/2 as much. On certain bikes it absolutely does work.

Wrap did no damge to the header in over a years use and no special treatment.

Edited by LILBIT, April 22, 2012 - 11:37 AM.


  • Aka.Goose

Posted April 22, 2012 - 11:47 AM

#6

I've eliminated overheating issues on my 07 by using a Boyeson water pump and Zip-Ty racing coolant...Before those two products, I used those temp strips (one on the radiator, one on the cylinder) to keep an eye on temp as I would boil over from time to time...Now I've removed the strips as I no longer need to worry about it...

  • Gunner354

Posted April 22, 2012 - 01:05 PM

#7

I've eliminated overheating issues on my 07 by using a Boyeson water pump and Zip-Ty racing coolant...Before those two products, I used those temp strips (one on the radiator, one on the cylinder) to keep an eye on temp as I would boil over from time to time...Now I've removed the strips as I no longer need to worry about it...

Don't want to bust your bubble but Zip-Ty racing coolant is Evans coolant renamed and at a higher price. The Boysen water pump is NOT needed with Evans or Zip-Ty coolant. How do I know? I run Evans in 2 09 YZ 450's and have never boiled over.

  • Aka.Goose

Posted April 22, 2012 - 05:01 PM

#8

Don't want to bust your bubble but Zip-Ty racing coolant is Evans coolant renamed and at a higher price. The Boysen water pump is NOT needed with Evans or Zip-Ty coolant. How do I know? I run Evans in 2 09 YZ 450's and have never boiled over.

No bubble burst, I've heard about the ZipTy coolant being repackaged from another brand, but whatever, it seems to work great, and very rarely needs changed, so I really don't care that it cost me only a few extra dollars over the past few years...ZipTy has been very helpful, with very reasonable prices, to me and a few friends I've refered to them...
And you may be right about the pump not being necessary, but I did that at the same time I started using the race coolant, and haven't had the slightest issue with overheating since (even in 100 degree plus dune riding, or slow woodsy family putt putts), so was just relaying the experience...

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  • Gunner354

Posted April 24, 2012 - 02:27 PM

#9

Wrapping the header in heat tape has one identifiable benefit: It keeps you from burning your leg on it. Other than that, anything it "does" is purely imaginary. With regard to the cooling system, the amount of heat transferred to the radiator by convention from a bare header is miniscule even in still air, and the least bit of air movement over the pipe essentially eliminates that.


The only real benefit of it is in applications where the engine is in a closed compartment where keeping the heat from the headers away from the intake system may be of value. Otherwise it has no performance benefit of any kind.

Some steel headers have been cosmetically damaged by header wrap retaining excessive heat (particularly chrome plated ones) but apart from that, it won't hurt the engine.

Wrapping the header does change the bottom end power. I wrapped a yfz450 header and noticed a slight change in bottom end power. I confirmed this with test equipment.

Edited by Gunner354, April 24, 2012 - 02:30 PM.


  • grayracer513

Posted April 24, 2012 - 02:58 PM

#10

grayracer-My KTMs header was within a 3/8 " of the radiator. After wraping from the head to just past the rads my fan ran 1/2 as much. On certain bikes it absolutely does work.

Wrap did no damge to the header in over a years use and no special treatment.


I don't doubt that the header was unharmed by the tape, since it's not chrome plated or steel (stainless steel is not steel). However, I invite you to place a 1 3/4" metal tube at that same distance from the radiators, unprotected by anything, and heat it to 650 degrees with the engine off and observe how long it takes to raise the temperature of the coolant in the radiators with no air flow.

Wrapping the header does change the bottom end power. I wrapped a yfz450 header and noticed a slight change in bottom end power. I confirmed this with test equipment.


I've established with "test equipment", including a dynamometer in at least one instance, more than once that header wrap makes no difference whatsoever in the performance of an exhaust system beyond isolating the intake tract from heat as noted earlier.

Believe what you like.

  • Gunner354

Posted April 24, 2012 - 09:10 PM

#11

I don't doubt that the header was unharmed by the tape, since it's not chrome plated or steel (stainless steel is not steel). However, I invite you to place a 1 3/4" metal tube at that same distance from the radiators, unprotected by anything, and heat it to 650 degrees with the engine off and observe how long it takes to raise the temperature of the coolant in the radiators with no air flow.



I've established with "test equipment", including a dynamometer in at least one instance, more than once that header wrap makes no difference whatsoever in the performance of an exhaust system beyond isolating the intake tract from heat as noted earlier.

Believe what you like.

I'm raising the BS flag!

  • grayracer513

Posted April 25, 2012 - 08:31 AM

#12

Wave it proudly.

  • RiderX

Posted April 25, 2012 - 08:38 AM

#13

Wrapping the header does change the bottom end power. I wrapped a yfz450 header and noticed a slight change in bottom end power. I confirmed this with test equipment.


What kind of test equipment did you use?

  • LILBIT

Posted April 25, 2012 - 01:23 PM

#14

I don't doubt that the header was unharmed by the tape, since it's not chrome plated or steel (stainless steel is not steel). However, I invite you to place a 1 3/4" metal tube at that same distance from the radiators, unprotected by anything, and heat it to 650 degrees with the engine off and observe how long it takes to raise the temperature of the coolant in the radiators with no air flow.

My test was not nearly as scientific as yours but i am convinced it helped. I could touch the bottom of the rads at operating temps with the tape on for a second. No way in hell to do so without. I have only the fans run time to go by and it was contolled by a thermostat. Run time did go down-not maybe.

That bike had cooling issues and even a small change made a difference.

I've seen headers glow at a stand still. Isn't that hotter than 650?

  • grayracer513

Posted April 25, 2012 - 02:52 PM

#15

I've seen headers glow at a stand still. Isn't that hotter than 650?


Yes it is. Red heat that's visible in the dark is about 750 ℉. Visible in low light like in a poorly lit garage, twilight, etc. is around 875. Visible in daylight is around 1000.

650 is a pretty typical running temp for "most" bikes, but a lot of that depends on cam timing, ignition timing, etc.

It's an interesting test to try, though, at any temperature. The heat has to cross the air barrier by convection. The next most probable path it will take is to disperse into the aluminum, which is fantastically good at that. On its own, it wants to eliminate hot and cold zones by dispersing the heat evenly throughout the entire mass as rapidly as it can. If the tank is sealed and crimped to the core assembly, there will be a thermal barrier at the joint, but not if the core is welded top the tanks. And yes, of course the coolant will pick up heat from the tank, but it takes it quite a while to do so.

My preference, if I wanted to address that issue, would be to build an stainless heat shield and stand it off of either the pipe or radiator tank, but the tape is simpler.

  • RiderX

Posted April 25, 2012 - 04:12 PM

#16

My test was not nearly as scientific as yours but i am convinced it helped. I could touch the bottom of the rads at operating temps with the tape on for a second. No way in hell to do so without. I have only the fans run time to go by and it was contolled by a thermostat. Run time did go down-not maybe.

That bike had cooling issues and even a small change made a difference.

I've seen headers glow at a stand still. Isn't that hotter than 650?


Depends on the amount of light around the exhaust, obviously, but it will start to glow in daylight at about 900-1000 degrees F. Most of the time when you see your head pipe glowing there is less light (as in near dark or in the garage, etc), which occurs at around 500-600 degrees F.

I'm with Gray on this one. Look at the laws of convection and work out the math/physics. Consider the small surace area of the head pipe directly under the bottom of the radiator, and since you are moving most of the time while riding you need to take into consideration air flowing all around the head pipe and radiator. The heating effect is negligible. If it where an issue the engineers behind the designs would have done something about it a long time ago. Even at a stand still your bike would boil over from the combustion heat before the head pipe would have a chance to make any difference.

  • LILBIT

Posted April 26, 2012 - 01:05 PM

#17

My preference, if I wanted to address that issue, would be to build an stainless heat shield and stand it off of either the pipe or radiator tank, but the tape is simpler.

On the second wrap job i covered it with an aluminum shield. Much easier to shape for a perfect fit than SS. More for wrap protection than anything else but it looked much better than mud/sand caked wrap.

I had forgotton more wrap on the same bike. With the oversize tank it would boil the fuel. You could hear it bubbling like an aquarium after a hard run in sand in the summer. 6" more wrap and cured.





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