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Zabrow187

09 YZ450f Overheating

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I have searched and found a few answers but nothing concrete.  My 09 YZ450f keeps overheating on single track trails, from what I can find it seems like a gearing change, rejetting and coolant change are what will fix my problem.  It has been suggested that I should swap out my water pump for an after market pump like a Boyesen , but do you all think that will fix my problem?

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Ultimately, since the problem is too little air flowing across the radiators, the best answer is fans, but on the YZ, these ahve to be driven by a battery.  Something as simple as computer chassis fans running off a couple of nine volts with an on/off switch can be a complete cure.

 

Fresh coolant at the correct dilution rate and a 1.6 bar cap will help, but it doesn't directly deal with the primary problem.  Likewise, expensive trinkets like the super cooler do help, but they won't cure the problem entirely because they don't address the cause.  They may nevertheless be enough to keep it from surfacing on your rides.

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Are you running stock pipe? If so take it apart and cut off the ice cream cone on one side, the full cone. I never had problems boiling unless it was with that pipe or too tall of gearing

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Ultimately, since the problem is too little air flowing across the radiators, the best answer is fans, but on the YZ, these ahve to be driven by a battery.  Something as simple as computer chassis fans running off a couple of nine volts with an on/off switch can be a complete cure.

 

Fresh coolant at the correct dilution rate and a 1.6 bar cap will help, but it doesn't directly deal with the primary problem.  Likewise, expensive trinkets like the super cooler do help, but they won't cure the problem entirely because they don't address the cause.  They may nevertheless be enough to keep it from surfacing on your rides.

 

This bike is my supermoto also, so it already has a battery.  

 

Are you running stock pipe? If so take it apart and cut off the ice cream cone on one side, the full cone. I never had problems boiling unless it was with that pipe or too tall of gearing

 

FMF Q4 and a Megabomb header.

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These are the conditions it over heats in.

 

 

Doesn't seem too slow of conditions. Although in the video angle it's impossible to see a trail through those trees.

 

Both of my built YZ'd WR450's one Supermoto and one dirt get straight coolant seems to act like Evans no boil over. At your speeds you might get away with a slightly higher cap pressure and a little less water and more coolant until there is no boil over. However as mentioned a fan is a great cure.

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Doesn't seem too slow of conditions. Although in the video angle it's impossible to see a trail through those trees.

 

Both of my built YZ'd WR450's one Supermoto and one dirt get straight coolant seems to act like Evans no boil over. At your speeds you might get away with a slightly higher cap pressure and a little less water and more coolant until there is no boil over. However as mentioned a fan is a great cure.

Can I get Evan's at a MC dealer?  I was directed to Engine Ice.  You almost can't see the trail at any vantage, it doesn't get a ton of traffic and with the leaves it's worse.

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Yeah, doesn't seem too slow... what is your gearing? do you have to ride the clutch the whole time? It didn't look like it, but the camera angle was hard to tell. What is your jetting???

 

I run regular auto coolant prediluted, with a 1.6bar tusk cap.. my fuel usually boils before my coolant. If I can putt along on this trail and not boil than you shouldn't have a problem where you are.

 

http://youtu.be/Z_RoZBTL5Yc?list=UU8YfHmaDC8Rp-YMafnuew6Q

Edited by n16ht5

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The Evans or any other straight coolant solution is a coverup, not a fix.  The way it work is that the Evans doesn't boil until around 400 ℉ someplace.  Now, there is something to be said for that, because in a liquid cooled engine, any liquid that is boiling from contact with the metal part isn't cooling anything, and of course, it is even less effective if it's out on the ground, or even in the recovery tank. 

 

However, all this approach does is allow your engine to run hotter than normal without boiling, and with Evans, the actual temperature of the head can go well past 400 degrees well ahead of boiling over.   I find this unacceptable.

 

Also, please note that almost all coolants are intended to be diluted, or like Engine Ice , already are diluted.  Straight ethylene or propylene glycol coolants, or oxalic acid coolants like Dexcool (which no one should ever use in their dirt bike) DO NOT transport heat as well as plain water, so the higher the percentage of coolant in the mix, the less capable it is of really cooling the engine.  Evans and Zip-Ty are reformulated to partially correct this, but are still not as good at actually carrying away heat straight water.

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Yeah, doesn't seem too slow... what is your gearing? do you have to ride the clutch the whole time? It didn't look like it, but the camera angle was hard to tell. What is your jetting???

I run regular auto coolant prediluted, with a 1.6bar tusk cap.. my fuel usually boils before my coolant. If I can putt along on this trail and not boil than you shouldn't have a problem where you are.

My gearing is 14/48 since this is my SM also, I run something close to my street gearing so I can run the same chain. I'm not riding the clutch but These are 2nd gear trails if you know the trails. My jetting is a 45 pilot and a 168 Main needle is 4th notch from the bottom.

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The Evans or any other straight coolant solution is a coverup, not a fix.  The way it work is that the Evans doesn't boil until around 400 ℉ someplace.  Now, there is something to be said for that, because in a liquid cooled engine, any liquid that is boiling from contact with the metal part isn't cooling anything, and of course, it is even less effective if it's out on the ground, or even in the recovery tank. 

 

However, all this approach does is allow your engine to run hotter than normal without boiling, and with Evans, the actual temperature of the head can go well past 400 degrees well ahead of boiling over.   I find this unacceptable.

 

Also, please note that almost all coolants are intended to be diluted, or like Engine Ice , already are diluted.  Straight ethylene or propylene glycol coolants, or oxalic acid coolants like Dexcool (which no one should ever use in their dirt bike) DO NOT transport heat as well as plain water, so the higher the percentage of coolant in the mix, the less capable it is of really cooling the engine.  Evans and Zip-Ty are reformulated to partially correct this, but are still not as good at actually carrying away heat straight water.

Agree with all that was said another thing to add to your disclaimer if you will, is Evans I know any ways is extremely flammable.

 

Unfortunately as you said Evens is capable of extreme temperatures and on some dirt bikes I.E. a ktm 50 they have plastic/phenolic Y pipes in the cooling system. At a youth National Hare and hound this year my buddies young son experienced first hand what can happen when the Evans gets to the point of melting plastic/phenolic parts. It melted right threw the Y pipe on his little bike and sprayed a fine mist all over him and the bike, then the evans proceed to hit the hot header pipe and ignited. Lets put it this way no one knows how long he was on fire for but when a sweep rider found him there were still flames on legs and the sweep rider actually was treated for burns on his hands from trying to extinguish him. He has mad a full recovery and nothing life altering just some cool scars. 

 

The point to all this is the manufactures have designed our cooling systems to work water based coolant. Adding a waterless coolant that has a drastically higher boiling point will just cause failures els where rather than just boiling over. You may as well stop using engine oil and use another product with better lubricity properties than engine oil and see how that works out. 

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Agree with all that was said another thing to add to your disclaimer if you will, is Evans I know any ways is extremely flammable.

Unfortunately as you said Evens is capable of extreme temperatures and on some dirt bikes I.E. a ktm 50 they have plastic/phenolic Y pipes in the cooling system. At a youth National Hare and hound this year my buddies young son experienced first hand what can happen when the Evans gets to the point of melting plastic/phenolic parts. It melted right threw the Y pipe on his little bike and sprayed a fine mist all over him and the bike, then the evans proceed to hit the hot header pipe and ignited. Lets put it this way no one knows how long he was on fire for but when a sweep rider found him there were still flames on legs and the sweep rider actually was treated for burns on his hands from trying to extinguish him. He has mad a full recovery and nothing life altering just some cool scars.

The point to all this is the manufactures have designed our cooling systems to work water based coolant. Adding a waterless coolant that has a drastically higher boiling point will just cause failures els where rather than just boiling over. You may as well stop using engine oil and use another product with better lubricity properties than engine oil and see how that works out.

There you go and sorry to hear about something like that.

But many in our group run straight antifreeze though not recommended.

I have two built 450's and they have been run very hard and on extreme slow trails and large hill climbs since 07 straight coolant. Still running no ill effects noted.

Edited by stevethe
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There you go and sorry to hear about something like that.

But many in our group run straight antifreeze though not recommended.

I have two built 450's and they have been run very hard and on extreme slow trails and large hill climbs since 07 straight coolant. Still running no ill effects noted.

Straight coolant meaning no water?

I am changing my gearing back to stock to see if it helps and putting a high pressure rad cap on.

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Straight coolant meaning no water?

I am changing my gearing back to stock to see if it helps and putting a high pressure rad cap on.

Yup I run straight coolant no water.

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If one were to monitor the temperature of the cylinder head during operation, he would see similar head temperatures with straight water at 200 degrees and with straight EG coolant at 240-250 or higher.  Straight coolant might be a solution for short runs in terms of coolant retention, but overall it simply does not transfer heat as well as water, and coolant mixtures loose the ability to cool parts directly as the percentage of coolant in the mix increases. 

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