CRF 150R Overheating

Perk

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#1
My cousin recently got a CRF 150R and this weekend while trailriding with his father and myself his bike started to boil over on several occasions. We were riding pretty tight, low speed terrain. While stopped and idling waiting on a slower rider, his bike started to idle pretty high and we noticed coolant spewing out from beneath the bike. After we got moving again it seemed to cool down and idle improved, but it started happening again later on in ride. Bike is bone stock and just came back from dealer after a cam recall. He is a pretty experienced rider for his age, but does not race or ride MX. Is this bike just not going to be happy trailriding in tight terrain?

Thanks,

Perk
 
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#2
I see it all the time at MX schools here in Fl. when kids are waiting their turn to hit an obstacle. Most all have said they're running engine ice too, so yes don't keep the bike still too long.
 
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#3
Yeah I have seen it with my son's 150 when riding some tight trails and having to sit and wait on someone to get going. But its never caused a problem. 2 or 3 oz of coolant is the most I've ever had to add and thats not been often. He races HS and does alot of trail riding.I have always used honda coolant since I got the bike new. But any good coolant should be fine.
 

KelvinKDX

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#4
I ended up using EVANS NPG COOLANT in a KX100 that was overheating in the woods when riden slow and climbing hills. Solved the problem completely. The stuff is a non-aqueous propylene glycol concoction with a boiling point of 370 degrees F. You have to get all of the water out of the bikes system before you use the coolant.

http://www.evanscooling.com/main27.htm
 
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#5
redline water wetter and water ro is the best because it is the cleanest. ro meaning reverse osmosis the way it is filtered like how dasani does theres. make sure you drain it before winter at least I have to because of good ol minnesota winters. oh yeah make it a 50/50 mix
 

Perk

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#6
So this bike should be ok in a hare scrambles type environment, just try and limit the still idling?
 

KelvinKDX

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#7
hot125mod said:
redline water wetter and water ro is the best because it is the cleanest. ro meaning reverse osmosis the way it is filtered like how dasani does theres. make sure you drain it before winter at least I have to because of good ol minnesota winters. oh yeah make it a 50/50 mix
The Redline should be an improvement over regular coolant but I do not think it will be as effiecient at cooling and reducing boil-over as the Evans NPG. The boiling point of the Redline is about 265F compared to 375F w/ the Evans. That being said the Redline should be much less expensive so I would try it first and if you still have the problems try the Evans. I had to use the Evans based upon the style of riding my wife was doing ... slow w/ lots of stopping and hill climbing.
 

KelvinKDX

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#8
You know ... that's something to think of. What is the jetting on the bike? I have heard the the 450's come pretty lean from the factory ... not sure about the 150R's.