Overheating Issue

Hey guys, i have a YZ450F and ride mainly woods/trail. The bike overheats and starts losing coolant after 5mins of riding. Is there anything i can do to fix this problem? Im currently using basic Prestone Coolant.

These are race bikes and need to be ridden fast enough to move air through the radiator for them to cool. They don't like to be ridden slow. If that is not the case the carb might need richened up a little.

How fast would you say you are going when it overheats?

Do a search for the pc fan mod. Basically you put a 90mm computer fan behind one of the radiator so even in tight single track you get sufficient airflow if you get a fan that pushes enough air. I had your same problem until I put on a pc fan. I did that and Engine Ice coolant, no more over heating!

Don't use coolant for diesel engines. It doesn't help it run cooler, it only raises the boiling point.

My 426 was over heating on me, I flushed the system and used engine ice. After 2 solid hours of woods riding it didn't over heat.

I'm going to try that fan mod anyway.

Thanks for the replies. I honestly cant get much past 1st gear, i hit 2nd for maybe 100feet then back to first. The track is too tight for high speed. Ad for the fan, where would you wire it into the bike seeing as there is no electrical system?

Ad for the fan, where would you wire it into the bike seeing as there is no electrical system?

Battery.

I would forego the fan and do what I did ....add the WR catch tank and use this instead of Engine Ice. http://www.evanscooling.com/

I still had issues on tight trails and on hot days with Engine Ice.... I was still losing coolant ....after switching to the Evans coolant I haven't had to add a drop to my catch tank.

I would forego the fan and do what I did ....add the WR catch tank and use this instead of Engine Ice. http://www.evanscooling.com/

I still had issues on tight trails and on hot days with Engine Ice.... I was still losing coolant ....after switching to the Evans coolant I haven't had to add a drop to my catch tank.

Depends on how you want to address the problem. The fan actually lowers the temperature of the coolant. Going with the Evans or Zip-Ty coolants just raises the boiling point to an extreme level so the cooling system can tolerate being hotter.

On the one hand, preventing boil over and coolant loss is a good thing regardless of how it's achieved. Coolant that is boiling is not cooling anything at the spot within the system where the boiling occurs, and coolant that is lost can't do anything to help. But Evans boils at close to 400 ℉, and even if it could transfer heat as well as water (which no coolant can), the parts being cooled have to be hotter than that to move heat from the source to the coolant. Look up the flash point of most good engine oils and you'll see that there's a potential problem in that alone.

In the extreme, where the only way to keep coolant in the engine through the ride is to use such stuff, then you pretty much have to do it, but it's far better to find a way to bring the temperature back into a more realistic range. Fans directly address the primary cause of the problem.

Would there be anyway to tie a fan into the factory stator? or would this aftermarket stator work to power a fan? http://www.electrosport.com/dirt-bikes/yamaha/yz450f-03-05/lighting-stator-yz250426450f-4-pole-35w.html

The stock stator has no provision to power anything other than the ignition. The Electrosport would do it for as long as it actually runs the bike, but they don't have a good record.

Contact Ricky Stator and see what they have for you. Remember that you have a YZ450F, NOT a YFZ450.

If you're concerned about the battery weight; The battery i use weighs about the same as my cell phone, far less than .5 pounds. A fully charged battery lasts me about 3 hours or more.

my 400 has holes drilled in the number plate with a steel mesh screen riveted to the back side to keep large debris and rocks out. its even adjusted a little on the lean side too. bike hasn't over heated in 13 years and it gets ridden pretty darn slow at times.

What does holes in the number plate have to do with cooling?

Okay so if i were to splice a small low wattage fans power and ground into the ignition systems power and ground this would not work?

negative

Okay so if i were to splice a small low wattage fans power and ground into the ignition systems power and ground this would not work?
Definitely not.
What does holes in the number plate have to do with cooling?

more air flowing to the radiators.

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