overheating, i need better coolant? maybe a fan?


74 replies to this topic
  • ThumperKid250F

Posted April 23, 2009 - 02:19 AM

#21

when does engine ice boil over and when does evans boil over..

i heard evans boils at 400 and engine ice is around 300? if thats true then wouldent you be hurting your motor by letting it run around 380 or 390 and it still wont boil over then oposed to engine ice running around 300..

only reason i asked this is that it seems like you would let your bike run hotter than is should by putting in a coolant that boils way over other coolants..

in short terms you would be over heating your motor and still not boil over right? does that make sense?

  • grayracer513

Posted April 23, 2009 - 09:38 AM

#22

I'm not a fan of running an engine quite that hot, but as I said before, sometimes keeping coolant in the system becomes more important than keeping the engine a few degrees cooler. Anyway, the fact that a coolant won't boil until 400 ℉ does not mean you have to run it that hot. In fact, not boiling the coolant is the whole idea. Once those bubbles start forming on the metal parts of the engine, they are no longer liquid cooled, and the actual head temperature will skyrocket.

As I mentioned earlier, water moves heat at a higher rate than any of the coolant mixes do, but if the water goes away, that doesn't help much. In answer to your question, under 16 psi (the standard 1.1 bar rad cap) Evans boils at something like 425 ℉, and Engine Ice or other 50/50 propylene glycol mixes at around 285. You can raise this temperature, or the boiling point of water, about 15~25 degrees farther by using a 1.6 bar cap.

  • x2468

Posted April 23, 2009 - 02:27 PM

#23

do any companies make a coolant temperature gauge? sounds like that would be a very useful addition. that plus evans coolant and the motion pro catch can and it sounds like an unbeatable combo. maybe even add the fan.

  • x2468

Posted April 23, 2009 - 02:30 PM

#24

Only by running it from a battery.


so it's not possible to run a fan on the YZ? or is there a way?

  • grayracer513

Posted April 23, 2009 - 02:56 PM

#25

so it's not possible to run a fan on the YZ? or is there a way?

Not if you try to power it off the YZ electricals. It's an ignition only system. You'd need a battery or an aftermarket stator with a lighting coil.

  • x2468

Posted April 23, 2009 - 03:10 PM

#26

perhaps maybe a lithium ion batter like the ones they use for helmet lights, hooked to a heat sensor so the fan only turns on above a certain temp (i saw one for sale in the same link as the fan). but i guess that'd be really going out of the way.

do you know of any coolant temp gauges that could be mounted somewhere on the bar? so that the rider could know when his bike is running dangerously hot with the coolant that doesn't boil over?

i have to say, the depth of knowledge in the yz450 forum, especially when pertaining to off-road riding, is actually steering me towards the yamaha. right now im between a used yamaha and a used kawi 450. (gray racer, you may remember the series of PMs i sent you around this time last year asking about the yz450f and what i should look for when looking for a used bike. I ended up getting a yz250 but it was stolen in the fall, so i find myself back in the same situation this season).

  • ThumperKid250F

Posted April 23, 2009 - 05:30 PM

#27

I'm not a fan of running an engine quite that hot, but as I said before, sometimes keeping coolant in the system becomes more important than keeping the engine a few degrees cooler. Anyway, the fact that a coolant won't boil until 400 ℉ does not mean you have to run it that hot. In fact, not boiling the coolant is the whole idea. Once those bubbles start forming on the metal parts of the engine, they are no longer liquid cooled, and the actual head temperature will skyrocket.

As I mentioned earlier, water moves heat at a higher rate than any of the coolant mixes do, but if the water goes away, that doesn't help much. In answer to your question, under 16 psi (the standard 1.1 bar rad cap) Evans boils at something like 425 ℉, and Engine Ice or other 50/50 propylene glycol mixes at around 285. You can raise this temperature, or the boiling point of water, about 15~25 degrees farther by using a 1.6 bar cap.


wow thats a big diff between when it boils.. the thing is when my bike over heats with engine ice i shut it off and let it cool down a little.. if i run evans coolant my bike is going to be running way hot untill it starts to puke it out.. i dont like that idea of my bike running 400degrees and not puking..

you think ill be ok if i run a diff cap, and a overflow tank the boyson water pump impeller and cover? with engine ice


i just really dont like the idea of my motor running that hot and not letting me no its running that hot by puking the coolant out, i got way to much money in my motor for me to cook it by running that hot

  • swatdoc

Posted April 23, 2009 - 09:56 PM

#28

2468 - the Trail Tech Vapor has a coolant temp sensor that mounts inline in one of your radiator hoses - that's what I use on my street legal YZ

  • ThumperKid250F

Posted April 24, 2009 - 03:12 AM

#29

yea my buddy had that on his wr and it was always reading a low temp for somereason

  • tcuda499

Posted April 24, 2009 - 02:21 PM

#30

Gray, if I was going to try to run a single fan off a batt, which would be the better side radiator to use as far as better cooling? Or do you think I would have to run 2 fans,one on each radiator?

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  • grayracer513

Posted April 24, 2009 - 02:29 PM

#31

I doubt it would matter which side to put it on. It would pull off the same amount of heat either way.

  • tcuda499

Posted April 24, 2009 - 02:43 PM

#32

Before i try it I will use my lazer heat probe to actually see if one side does get hotter. I dont know why I didn't think of that earlier....:banghead:

  • grayracer513

Posted April 24, 2009 - 03:05 PM

#33

The left side will be hotter than the right because the hot water from the engine enters on that side, but that still doesn't mean that positioning the fan there will have more of an effect that positioning it on the right.

  • swatdoc

Posted April 24, 2009 - 03:09 PM

#34

I'd try one fan first. if you go with the Spal fan, whichis the one ktm uses in their aftermarket fan kits, it pulls about 30 watts. So with 2 fans, you're lookin at 60 watts, which is gonna suck down a battery fast!
Gray - correct me here if my thinking is wrong, but wouldn't a puller fan be the correct model when mounting on the rear side of a radiator, since that's the normal direction of airflow?

  • grayracer513

Posted April 24, 2009 - 03:13 PM

#35

Gray - correct me here if my thinking is wrong, but wouldn't a puller fan be the correct model when mounting on the rear side of a radiator, since that's the normal direction of airflow?

That's right. If it were me, I'd crawl through an electronics surplus house and find a suitable 12v, low draw fan for under $10 and adapt it.

If you're running an oversized tank, there may not be enough space to place a fan on the back side of the radiator.

  • tcuda499

Posted April 24, 2009 - 03:27 PM

#36

I was looking at Spal fans,$75 for a trial is alittle high. I'll look for a cheap one first.

  • swatdoc

Posted April 24, 2009 - 04:22 PM

#37

the cheaper fans are something to try i guess - but how waterproof are they? and i just can't see how they'd pull as much cfm's as a fan like the spal would. price is a lot better though!
if you think the $75 is pricey - check the price of the kit from ktm - over $100

  • grayracer513

Posted April 24, 2009 - 08:19 PM

#38

The waterproofing question is one to consider. As to the air volume moved by the fan, first, small electric fans come in all manner of capacities. It's something to look at when buying, certainly. The second question that comes up is whether one needs the volume delivered by the Spal fan or not. The Spal could well be worth every penny in the end, but what I'm saying is that on an experimental basis, there are cheaper alternatives that could tell you if you're on the right track.

  • swatdoc

Posted April 24, 2009 - 08:45 PM

#39

OK i see what you mean - cheaper to experiment with an inexpensive fan, then if it works well, upgrade to a reliable/waterproof fan.

  • tcuda499

Posted April 26, 2009 - 05:43 PM

#40

well I do have a clarke 2.6 tank.....it might be tight,very tight. Would you say using a pusher fan and move the rad louvers out a couple inches would be out of the question???? It now seems that a simple fan will turn into a little project.:banghead: thats what I like.:banghead:





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