WR250R Engine Heat

[scottmac]

I've got almost a 1000 miles in on mine and I'm seeing

a trend of lot's of heat buildup in the motor on slow,

tight singletrack riding.

I've had the cooler fan kick on like mad on about 5

different rides now. Most of these have been up

under the trees or early mornings.

I'm starting to think the single side radiator just

isn't up to the task, hate to think what it would

do down in the desert.

I kinda wish that Yamaha would just have gone

with a second radiator wing and lost the high

tech sensor/fan setup.

If you're ever out lugging it in the heat and that fan dies

you're screwed.

[JasonfromMN]

I've got almost a 1000 miles in on mine and I'm seeing

a trend of lot's of heat buildup in the motor on slow,

tight singletrack riding.

I've had the cooler fan kick on like mad on about 5

different rides now. Most of these have been up

under the trees or early mornings.

I'm starting to think the single side radiator just

isn't up to the task, hate to think what it would

do down in the desert.

I kinda wish that Yamaha would just have gone

with a second radiator wing and lost the high

tech sensor/fan setup.

If you're ever out lugging it in the heat and that fan dies

you're screwed.

I've experienced the same on the slow stuff... Fan runs ALOT!

[nocturnal]

I bet the FI is mapped to run very lean from the factory so the bike can pass EPA standards. A lean condition will make a bike run hot.

[2wheelterra]

I've experienced heat on my lower right leg when I get stuck in traffic, much the same speed as you describe. I'm considering putting some WaterWetter into the coolant to drop the temps a bit. It helped on my road bike, so I'm hoping for some benefit here. I also agree with the lean condition statement, getting the FI mapped properly couldn't hurt.

[reconranger]

Lean was my first impression.

The Redline Water Wetter is a good suggestion as well. In hot weather where there is no chance temperatures will ever reach freezing, your best cooling will be distilled water with Water Wetter. It contains corrosion inhibitors, so that isn't an issue. Go back to antifreeze for winter.

[hunkybizkit]

"Compression ratio 11.8:1"

i'm assuming that you are using super unleaded gasoline 92/93 octane. i'm not positive, but if you happen to be running 87 octane i think it can cause precombustion/engine heat problems.

[SjSabre]

Lean was my first impression. The Redline Water Wetter is a good suggestion as well. In hot weather where there is no chance temperatures will ever reach freezing, your best cooling will be distilled water with Water Wetter. It contains corrosion inhibitors, so that isn't an issue. Go back to antifreeze for winter.

Is that the same stuff as "engine ice"? Somebody reccomended engine ice for my wr250r....

Direct Quote from their web site:

"Engine Ice Hi-Performance Coolant is biodegradable, phosphate free & non-toxic; while reducing operating race temperatures by as much as 50°F and effectively keeping boil over temperatures to 256 °F or less and freeze-up protection to -27° F."

http://www.engineice.cc/

[2wheelterra]

Is that the same stuff as "engine ice"?

It's very similar:

"WaterWetter® is a unique wetting agent for cooling systems which reduces coolant temperatures by as much as 30ºF. This liquid product can be used to provide rust and corrosion protection in plain water for racing engines, which provides much better heat transfer properties than glycol-based antifreeze. Or it can be added to new or used antifreeze to improve the heat transfer of ethylene and propylene glycol systems. Designed for modern aluminum, cast iron, copper, brass and bronze systems. Compatible with all antifreezes, including the latest long-life variations."

Redline WaterWetter

[scottmac]

I've been running Premium, 92 octane in mine as per

factory recommendations.

Another thing that may be a factor is the new aluminum

skidplate. It's covering a large portion of the case and

has no ventilation holes drilled in it.

[ro7939]

"Compression ratio 11.8:1"

i'm assuming that you are using super unleaded gasoline 92/93 octane. i'm not positive, but if you happen to be running 87 octane i think it can cause precombustion/engine heat problems.

IMO, negative. Modern FI & computer controll systems include anti-knock sensors. Lower fuel octane (within an operational range) should simply cause less ignition advance & lower power/efficiency but should NOT pre-ignite &/or cause excess heat.

One of my vehicles had noticably less power running on regular vs. premium but the regular caused no pre-ignition.

All bets may be off w/ carburetors. FI is one of the several feathers in the WR250R's cap.

[Jim01]

Sorry for bringing up a old thread. I was searching on wr250r running hot. I haven't rode mine enough to fine out ,only had it a few months. Is this going to be an issue putting around in the hot humid Alabama summer say Aug threw trails (1st,2nd maybe 3rd gear)?The reason i ask i have seen people say they see 4t puke coolant on slow single tracks.

Thanks

Jim

[derangedhermit]

I've got almost a 1000 miles in on mine and I'm seeing a trend of lot's of heat buildup in the motor on slow, tight singletrack riding.

I've had the cooler fan kick on like mad on about 5 different rides now. Most of these have been up under the trees or early mornings.

I'm starting to think the single side radiator just isn't up to the task, hate to think what it would do down in the desert.

I kinda wish that Yamaha would just have gone with a second radiator wing and lost the high tech sensor/fan setup.

If you're ever out lugging it in the heat and that fan dies you're screwed.

It's working like it is supposed to. Try to learn to appreciate the sound of the fan. Fans are not particularly likely to fail. That one radiator with fan can dump more heat that the WR250F 2-radiator setup.

Is that the same stuff as "engine ice"? Somebody reccomended engine ice for my wr250r....

Watter wetter and engine ice aren't the same thing at all.

Watter wetter is simply the "additives" found in regular coolant, without the coolant. Stuff to protect aluminum parts, reduce surface tension, etc. Running straight water in the cooling system isn't a great idea for long term use, so adding a little watter wetter to straight water helps keep the cooling system in good shape.

Engine Ice is a complete coolant, based on propylene glycol (like Sierra and some others for cars), and marketed towards motorcycles. Safer than ethylene glycol, especially if dogs are around. It's just an alternative coolant.

IMO, negative. Modern FI & computer controll systems include anti-knock sensors. Lower fuel octane (within an operational range) should simply cause less ignition advance & lower power/efficiency but should NOT pre-ignite &/or cause excess heat.

One of my vehicles had noticably less power running on regular vs. premium but the regular caused no pre-ignition.

FI is one of the several feathers in the WR250R's cap.

The WR250R/X engine does not have a knock sensor.

[Longview]

Thanks for posting DH - I was left wondering why people were concerned that it was running too hot just because the fan comes on...

[Jim01]

Thanks guys.I'm not worried about the fan running. I was just reading about guys loosing coolant ,not necessarily on wr250r's but 4strokes. And was worried about putting around following my wife until she gets more experience.

Thanks again

Jim

[derangedhermit]

Thanks guys.I'm not worried about the fan running. I was just reading about guys loosing coolant ,not necessarily on wr250r's but 4strokes. And was worried about putting around following my wife until she gets more experience.

Thanks again

Jim

People have ridden them for at least one summer in a lot of conditions now, on and off road. Daily commuting in SoCal traffic, California and Oklahoma offroad hard rides, etc.

It doesn't seem to be an issue with this machine.

I *have* read of other (offroad) water-cooled 4 strokes belching coolant. IIRC, some of the Euro models were the worst, but I seem to recall a few Yamaha models would do it also.

I honestly wouldn't worry about it at all. It doesn't get that hot in Alabama, and ambient temp is the biggest factor in efficiency of fan-cooled radiators. You also have a decent sized expansion bottle for when things heat up. If you want, for peace of mind, you might cast an eye on the level in that bottle on your first few trips.

[Jim01]

Thanks

Jim

[JasonfromMN]

I ride alot of single track and have heard the fan alot, but never seen the temp light come on. Furthermore when this thread was new, and I really paid attention to the fan, even though I heard it turn on alot, I heard it turn off alot. That means its getting back down to normal operating temp well.

[scottmac]

Since I started this thread I've gone over to using Engine

Ice and it's helped a lot. Guess I'm just Old School but

the sound of that fan kicking on and buzzing away

makes me start thinking that things are getting too hot.

I just recently put on that new aluminum Force Radiator

guard and have removed the stock black plastic cover

that goes over the fan. From what I've heard this also will

improve airflow to the radiator and help to reduce heat buildup.

We'll see how it all adds up when summer and hotter

weather roll back around again this year.

[jecottrell]

scottmac brought up the point that I was thinking as I read the entire thread...

I noticed fan running a lot less after trimming the air deflector on the rear of the radiator fan shroud... and even less after installing the Force radiator guard. However, my right shin is now the heat sink for the hot air as opposed to the head, where the heat used to be pointed.

.

[Thumpthing Old]

I've had my temp warning light come on a couple of times riding in the desert. Both times I was cruising along steadily at about 1/2 throttle with a steady tailwind. The tailwind killed the airflow through the radiator and the fan wasn't enough to keep the engine cool. Turning into the wind, or or outrunning the tailwind made the light go out.