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GrumpyDog

05' 450X Radiator Temp & Pressure questions.

18 posts in this topic

I bought a Trail Tech Vapor , and can set warning lights for both "Warning Temp" and "Dangerous Temp". I am trying to figure what temp to enter for these lights to come on. The bike is an 05' CRF450X. Golden Rule: Keep the CRF450's moving or they will over-heat very quickly. Anyone have an idea what the temp ranges are for these bikes, and are they pretty much the same for every year of the 450X (helpful for other users)? I have rad-guards, so this even restricts air-flow that much more. Also, any insight on the pressure ratings for the radiator caps? If I change out for a different rating, how does that affect the bike, both positive and negatively? Are there any caps or set-ups that recommended?

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I bought a Trail Tech Vapor , and can set warning lights for both "Warning Temp" and "Dangerous Temp". I am trying to figure what temp to enter for these lights to come on. The bike is an 05' CRF450X. Golden Rule: Keep the CRF450's moving or they will over-heat very quickly. Anyone have an idea what the temp ranges are for these bikes, and are they pretty much the same for every year of the 450X (helpful for other users)? Also, any insight on the pressure ratings for the radiator caps? If I change out for a different rating, how does that affect the bike, both positive and negatively? Are there any caps or set-ups that recommended?

Unfortunately, I won't be able to help too much here, but I'm also interested in the subject. I just put one on, and after a nasty little ride here down by Tucson, my max temp for the day was 238.

No indication of overheating.

I left the warnings at factory default.

Looking forward to seeing some more responses.

JC

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The owners manual for the X gives absolutely no indication of ideal operating temp and overheating temp.

A lot of people use engine ice in their rads which will prevent boil over up to 260 degrees. Chances are, ideal operating temp is around 200. That's just based on the experiences of working with lots of liquid cooled bikes in general, mostly street bikes, but all the same rules should still apply.

On my Vapor, I set my warning at 215 and overheat at 250. When the yellow light comes on, I pick up the speed to get some more airflow or I drop a gear. For me, the yellow light is simply a warning to me to get my butt in gear. When the red comes on, I pick up the speed or I pull over and take a break for a while.

The only time I see red is when I do a lot of successive steep, slippery hill climbs where I'm crawling up and slipping the clutch a lot rather than spinning my tire by trying to use pure HP.

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I just saw a note on CRF's Only that says "High Temp: 210 Dangerous Temp: 230" I am going to keep looking though to see what else I can find.

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I just saw a note on CRF's Only that says "High Temp: 210 Dangerous Temp: 230" I am going to keep looking though to see what else I can find.

That sounds "about right" from what I remember (I no longer have a TTVapor on my bike). I ran 220 for high and 230 as dangerous. Never really got into anything too hot, and I didn't want yellow coming on all the time. All it does if set too low is annoy you, or scare you into going faster when it's truly not needed.

I think the hottest was in 108°F heat and it still didn't get "up there" unless I was winding it out in sand (and not going anywhere), or in a severely rocky section and too heavy on the clutch abuse... errr, I mean "use". :lol:

... even with my flatland rad guards , never in the red.

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Thanks JAT, I agree that playing with temps is going to be the key. The all-out important temp is the "dangerous" temp at 230. A lot of our trail riding are on single-track and pretty tight, so unfortunately we are crawling along in 1st and 2nd a lot, so the bike starts spitting out steam from it's vent-line all through-out the day.

On a side note, someone had mentioned that I may want to re-jet to a richer set-up to help keep the bike cooler. Ever heard of doing this or if there is any truth in it? I'll rebuild forks and electrical systems all day long, but I have no clue about the *!$% carb! I wish I could sit down and take a class on how an FCR carb works.

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A lot of people use engine ice in their rads which will prevent boil over up to 260 degrees. Chances are, ideal operating temp is around 200. That's just based on the experiences of working with lots of liquid cooled bikes in general, mostly street bikes, but all the same rules should still apply.

On my Vapor, I set my warning at 215 and overheat at 250. When the yellow light comes on, I pick up the speed to get some more airflow or I drop a gear. For me, the yellow light is simply a warning to me to get my butt in gear. When the red comes on, I pick up the speed or I pull over and take a break for a while.

The only time I see red is when I do a lot of successive steep, slippery hill climbs where I'm crawling up and slipping the clutch a lot rather than spinning my tire by trying to use pure HP.

Do you use the Engine Ice? And if so, did you set the 215 and 250 temps after you were using it? Thanks X1glider for informative write-up.

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And if so, did you set the 215 and 250 temps after you were using it? Thanks X1glider for informative write-up.

i believe x1glider set those the temps in his vapor based upon boiling points and chose temps right before boiling as warning indicators. water alone boils at 212 degrees farenheit. a 50/50 mixture of water and ethylene glycol antifreeze in the cooling system will boil at 225 degrees if the cap is open. But as long as the system is sealed and holds pressure, a radiator cap rated at 15 psi will increase the boiling temperature of a 50/50 coolant blend up to 265 degrees. If the concentration of antifreeze to water is upped to 70/30, the boiling temperature under 15 psi of pressure goes up to 276 degrees.

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i believe x1glider set those the temps in his vapor based upon boiling points and chose temps right before boiling as warning indicators. water alone boils at 212 degrees farenheit. a 50/50 mixture of water and ethylene glycol antifreeze in the cooling system will boil at 225 degrees if the cap is open. But as long as the system is sealed and holds pressure, a radiator cap rated at 15 psi will increase the boiling temperature of a 50/50 coolant blend up to 265 degrees.

You did good in following my logic, Ivan. What you say is true. Also, I go by some years of experience as a guy who did some wrenching as a ASE certified mechanic in addition to my engineering job.

I know for certain that you can intermittently hit 260 degree coolant temperatures and not damage an all aluminum engine. The combustion chamber is tremendously hotter than that and it will take a lot of time at high coolant temperatures to make the materials expand any more than they already have. For the most part, combustion chamber temperatures stay constant. All coolant does is help the engine maintain a somewhat stable temperature and material state. It will, however, take less time to bring the total engine temps down once you start moving again and get the coolant temps down.

If the concentration of antifreeze to water is upped to 70/30, the boiling temperature under 15 psi of pressure goes up to 276 degrees.

Yes the boiling point goes up, but the ability to remove heat goes down. Coolant is actually not very good at removing heat.

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Do you use the Engine Ice? And if so, did you set the 215 and 250 temps after you were using it? Thanks X1glider for informative write-up.

Yes, I use engine ice. I originally set the temps even when using regular coolant. I noticed a slight difference in lower temps with the engine ice. Keep in mind, a radiator needs to be properly "burped." Air in the closed system will cause overheating. I think this is a lot of people's problem.

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Yes more fuel will cool down a engine. More important to have everything up to spec and the engine jetted for best running. If your to lean it can cause the coolant system to work harder.

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Keep in mind, a radiator needs to be properly "burped." Air in the closed system will cause overheating. I think this is a lot of people's problem.

"Burping" the rads! Now there's a saying that will stick in my head. I probably do have some air in the system. Other than the obvious "topping it off" routine, what's the best way to get most of the air out of the system?

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More important to have everything up to spec and the engine jetted for best running. If your to lean it can cause the coolant system to work harder.

I think you are on to something with the jetting. I still have the factory set-up, which I heard comes pretty lean. I've read that by making it richer, will make it run cooler? I have no idea why though. I think I am going to have research some suggested jetting sizes for this carb. I've openned and/or rebuilt just about everything on the bike, except for the carb. I've honestly got to say that I have no idea how the damn thing works!

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"Burping" the rads! Now there's a saying that will stick in my head. I probably do have some air in the system. Other than the obvious "topping it off" routine, what's the best way to get most of the air out of the system?

Fill, run, fill, run... cap off. Watching the water pump push water over the top of the radiator.

I think you are on to something with the jetting. I still have the factory set-up, which I heard comes pretty lean. I've read that by making it richer, will make it run cooler? I have no idea why though. I think I am going to have research some suggested jetting sizes for this carb. I've openned and/or rebuilt just about everything on the bike, except for the carb. I've honestly got to say that I have no idea how the damn thing works!

More rich = cooler operating temp

... same with higher octane fuels. It too changes the jetting spec, and operating temp of the bike.

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I run my vapor at 210 and 225, maybe Ill change it to 230 on the red light, I do tend to hit the yellow light when Im crawling around in slow stuff beating the crap out of the clutch. Since going up two teeth on the rear it has seemed to help the over heating. Do be to intimidated buy the carb, get a service manual from honda (i know they are expensive but worth there weight) and take your time, it really isnt hard. Id hardly ever been in a carb let alone rejeting and whatnot, the s/m made it cake.

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On a side note, someone had mentioned that I may want to re-jet to a richer set-up to help keep the bike cooler. Ever heard of doing this or if there is any truth in it?

Yes, rich en the fuel mixture and cool the engine temp:prof:

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Alrighty, well I put in a JD Jet Kit, did the O-Ring modification to the pump on the FCR carb, opened the air-box, switched to Engine Ice , put in a stainless oil filter , new air-fuel misxture screw, checked valve clearances (ggod) along with countless other modifications............Holy Crap!!!! This things runs beautifully for the first time ever! Took me a while to really dial it all in (also completely rebuilt the forks), but thing definiltey runs cooler now and has no bog what-so-ever now. One weekend of just work and the machine is nasty responsive now. Thanks everyone for the help and the suggestions!

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Prety amazing to see the difference between what the MFR/EPA/CARB thinks is acceptable performance and what the end user sees as acceptable performance.

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