Upgrade radiator? (overheating issues)

[Hurricane]

I have to say that the Evans has worked for me. Ive never boiled with it but try to be careful of times when the bikes building heat. Ive done the neverending uphill rut when your stuck a gear high and cant get to the shifter or pushing the bike out of the swamp from hell. I dont let the bike idle for long either. It mat get hot but the coolant stays in the rad. Better than boiling it out and riding with no coolant. I was going to put a overflow tank on but it ended up being unecessary. I used it in my 08 from new so the cooling system was good to start with and air temperatures varied between freezing and 30 degrees Celsius. I could always tell when my bike was probably hot by when OTHER guys bikes were puking. The Hondas especially.

+1 on the Evans in my 2007 yz450. You can tell when it's getting hot and just shut it down but I don't have to worry about draining my drinking water into the radiators to make it back 25 miles to the truck!? Almost all 4 strokes overheat in tight conditions and they either puke the fluid into a catch tank or puke it onto the ground. I don't have a catch tank but the Evans acts like one. I can tell when my bike is too hot and know whether or not to shut it off or keep pushing.

[dalonar]

computer fan $10 or free......9 volt battery, rc pack, hell a cheap 12v drill battery.....for $50 or less you can make your bike never run "hot". Also masking the problem with super duper coolant dosn't fix the issue.

[Gunner354]

computer fan $10 or free......9 volt battery, rc pack, hell a cheap 12v drill battery.....for $50 or less you can make your bike never run "hot". Also masking the problem with super duper coolant dosn't fix the issue.

How long will the fan run on that 9v battery? How cool is your bike running with this setup?

[grayracer513]

Actually, a single 9v alkaline cell will run a 200ma computer case fan (about 35 cfm) for at least 4 hours. A fairly inexpensive rechargeable 12v NiMH pack would run it for well over 10 hours straight, and LiPO's will do much more. The temperature may not be specifically quantifiable, but it won't boil with a normal high quality EG or PG coolant mixed at 50/50 under a 16 psi cap running two such fans. Add a handlebar switch and turn it on only when called for, or get fancy and install a thermostatic switch.

There's nothing super secret about Evans (also sold as Zip-Ty) coolant. It is simply a mix of glycols, predominantly propylene glycol, and formulated to be run without water. You can, in fact, run most fairly ordinary coolants, PG's in particular without water and get a higher boiling point by doing so, but you run the engine hotter because of it, since the plain truth is that plain water with a surfactant added cools better than any glycol coolant, straight or mixed with water can. The only thing really different is the slightly lower viscosity that allows it to circulate more freely. It actually will not keep the engine as cool as a mixed coolant or water will as long as there is adequate air flow and coolant circulation, and boiling is controlled, and I saw nothing on their web site suggesting otherwise.

I did see kind of a "Captain Obvious" moment, to wit: "In a 100° F environment a radiator that is 250° F will dissipate 25% more heat than one at 220° F." Well yes, the greater the temperature difference between the radiator and the air, the more heat moves to the air, but so what? Is there then supposed to be an advantage to running the engine hotter in order to shed more waste thermal energy into the air? Understand that this is exactly the same as saying that a radiator at 220℉ in a 70℉ environment will shed 25% more heat than one in a 100℉ environment (with the same shaky thermodynamic math). Following that logic, it would be better, I suppose, in 100 degree weather, to run the coolant at 300℉, since that way the radiator could dissipate 67% more heat than it did at 220. Somehow, I don't feel inclined to do that, but maybe that's just me. Interesting sales pitch, though.

The YZ450 does not overheat when used as intended unless it has an addressable mechanical fault. But it is not intended to operate for extended periods at low speeds, and is therefore not equipped, as built, with the one thing it needs most in order to replace that which goes away when you slow to a crawl, and that is a way of providing air circulation over the radiators. Fans fix that while leaving the rest of the system and its designed temperature range intact.

[Wiz636]

I run my own mix of 20% PG coolant, 80% water, and a splash of surfactant (Water Wetter) and NEVER boil over.

[Gunner354]

Is there actual evidence of before and after data regarding the fans and battery life?

[eflyguy]

Any pics of where to mount the fan(s)? Worried about it getting soaked when cleaning the bike.

I searched and browsed back thru several pages of results with no luck..

..a

[grayracer513]

Is there actual evidence of before and after data regarding the fans and battery life?

Yes. The spec sheets of the batteries and the fans.

Any pics of where to mount the fan(s)? Worried about it getting soaked when cleaning the bike.

I searched and browsed back thru several pages of results with no luck..

..a

The easiest place to mount the fans is usually on the back side of the radiators, since that doesn't involve cutting away any of the louvers from the front. The are best mounted as close as possible to the radiators, and some will simply zip tie them directly to the core, using foam tape to protect the radiators. I would prefer something a bit more robust than that, bolted to something other than the core. Some radiator cages/braces offer several places to anchor to, but the radiator frame should be strong enough, too.

Most of the fans are reasonably well sealed, and the motors are brushless, so there aren't any sensitive contacts to be concerned with. They're also usually dirt cheap (under $10), so if one fails, it's not the end of the world.

[Hurricane]

The YZ450 does not overheat when used as intended unless it has an addressable mechanical fault. But it is not intended to operate for extended periods at low speeds, and is therefore not equipped, as built, with the one thing it needs most in order to replace that which goes away when you slow to a crawl, and that is a way of providing air circulation over the radiators. Fans fix that while leaving the rest of the system and its designed temperature range intact.

I agree that yz450 was not really designed for the slow speed but wasn't the the WR450 designed for trail riding which ussually involves alot of slow speed riding? If so I wonder why Yamaha doesn't install a fan on them from the factory. As a former WR owner I think my WR overheated easier than my yz does in the same riding conditions and all Yamaha really did was a put a catch tank on it. Seems like the engineers at Yamaha would have thought about a fan over a catch tank.

[Gunner354]

I agree that yz450 was not really designed for the slow speed but wasn't the the WR450 designed for trail riding which ussually involves alot of slow speed riding? If so I wonder why Yamaha doesn't install a fan on them from the factory. As a former WR owner I think my WR overheated easier than my yz does in the same riding conditions and all Yamaha really did was a put a catch tank on it. Seems like the engineers at Yamaha would have thought about a fan over a catch tank.

Agree! Most people know when they are in boiler over conditions so just be aware of that and run Evans. The motor is NOT going to explode from being to hot if you just use plain ole common sense. Simpler is just easier in this scenario.

[grayracer513]

It seems that way to me, too, and if you look at most quads, even the "racing" models, you see they have fans from the factory. But even KTM, whose bikes are arguably much more targeted to competitive off-road use than the WR, also omits fans from their line.

[Hurricane]

Agree! Most people know when they are in boiler over conditions so just be aware of that and run Evans. The motor is NOT going to explode from being to hot if you just use plain ole common sense. Simpler is just easier in this scenario.

I agree if I think the bike is running too hot I shut it down. When I had my WR if it overheated, guess what I shut down. So to me the evans is like a catch tank in that you don't lose your coolant if the bike does get to hot.

[Hurricane]

It seems that way to me, too, and if you look at most quads, even the "racing" models, you see they have fans from the factory. But even KTM, whose bikes are arguably much more targeted to competitive off-road use than the WR, also omits fans from their line.

KTM does sell an aftermarket fan kit in their hard parts catalog, does Yamaha?

[eflyguy]

Nothing on the accessory site.

Thanks for the info. I can figure stuff out, but if it's been done and people have run into issues, I'd rather learn from their experiences!?

..a

[grayracer513]

KTM does sell an aftermarket fan kit in their hard parts catalog, does Yamaha?

KTM is mighty proud of that kit, too ($$$). I don't recall seeing one marketed by GYT-R, no.

[Hurricane]

KTM is mighty proud of that kit, too ($$$). I don't recall seeing one marketed by GYT-R, no.

Yes I've heard, my friend saw the price of theirs and built one using a computer fan for his ktm300.