Yz450f radiator cap thoughts?!?

What's a good non-stock radiator cap? I have a 2006 yz450f with oversized radiators. I've read many different forums and no one has really gave valued info on the subject so looking for a little help..

I mainly trail ride with the occasional track ride, bike gets hot pretty quick and overheats quite often, looking for a way to alleviate that as much as I can (I know it'll still get hot and sometime overheat).

So I guess here's my two questions

1. What size radiator cap would be best?

2. What coolant is good or best to use?

Thanks in advance

Search the word "coolant"


Add a fan to your bike.

Edited by boney95

The source of the overheating issue in this case is a lack of air over the radiators, so the best fix for it is to provide more air flow through the use of radiator fans. Small, light computer chassis fans can be mounted one on each side, and can be run from one or two 9v batteries with a switch for 3-4 hours of run time.  This cures the actual problem.


Radiator caps control the cooling system pressure, and the higher the pressure, the higher the boil over point.  The stock cap holds 1.1 bar (16 psi).  You can get a cap to fit a 2000 Toyota Corolla, or Honda Accord that holds 1.6 bar (21psi), and that will raise the boil temp from about 265 to about 280.  Raising the system pressure carries with it the obvious risk of blowing a hose, and if you've never been scalded, well...


Any good propylene glycol coolant can be used to improve the boil over point by about 5+ degrees over ethylene glycol (the green stuff).  Engine Ice is premixed and ready to use, but it's pricey compared to generic automotive PG's.  Zip-Ty and Evans market a waterless coolant that won't boil until 400+ degrees, but running your engine that hot is hardly advisable. 

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