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XR250R engine oil temperature when running?

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Thanks but the chart doesn't seem to be displaying.

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Went on a ride this weekend and found that it was getting up to 275*F when working through the sand on uphills.

 

Also found that the bike kick starts first kick when the temperature is between 100 - 200*F, but over 200*F becomes hard to start and I often had to resort to roll starting.

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Yeah, that's too high IMO. Did you ever sense an odor of hot/burning oil? You'll often smell it coming from the crankcase vent line. When the oil gets too hot it will often foam. When that happens, all you have is a film of tiny bubbles coating and trying to lubricate your internals. That condition doesn't conduct heat away from internals very well. And I don't imagine the oil pump handles foamy oil very well either.

 

I started adding a product called Two2Cool to my oil several years ago to combat this issue after I did my 440 big bore kit. The stuff works. Brought my oil temps down 20*.

 

With the 250 having no oil cooler, couldn't hurt to try it. Run a good full synth oil too.

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Uphill in sand is a tall order for a 250.  Is this a stock engine or built up with a high compression piston?  Are you running a paddle tire?

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OK, cool.  Your bike is a high compression XR284R.  Calling it an XR250 is a bit misleading.  Now I can see why you would want to add more cooling capacity.  

 

Baja trail rider has built some XR300s from the late model XR250s.  They have the frame reservoir, XR400 cooler, and XRS Only big fin heads, but stock compression for reliability.  Those heads may not be available anymore.  

 

You can shave the piston down to stock compression.  That will reduce some heat and, of course, power.

 

I installed a 250 oil cooler on my stock XR250L.  It has made a world of difference on a bike that had no external reservoir or cooler. 

 

Here are photos of the aluminum side mounts and steel tab mount.  They are glued on but I have a lot of expertise in that area.  The side mounts are sized for an XR400 cooler upgrade if needed.  

 

Oilcoolersidemount0592.jpgOilcoolertabmount0595.jpg

 

 

 

 

 

 

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OK, cool.  Your bike is a high compression XR284R.  Calling it an XR250 is a bit misleading.  Now I can see why you would want to add more cooling capacity.  

 

 

For sure, no wonder its running hot. A stock 250 would get pretty warm pulling sand hills, let alone a high comp big bore. Tho, you really didn't go up that much more over the stock 10.2:1. Every little bit contributes.

Edited by Trailryder42

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Two other thoughts:

 

1. Do you have a XR front fender? A fender from a water cooled bike will block air flow to the engine.

 

2. Use a high quality synthetic oil of at least xx-50, some Harley oils are available in that range. 

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Two other thoughts:

 

1. Do you have a XR front fender? A fender from a water cooled bike will block air flow to the engine.

 

2. Use a high quality synthetic oil of at least xx-50, some Harley oils are available in that range. 

 

1. No, I have an aftermarket front fender, but it's got slots in the back to allow the air to flow through.

 

2. I think I do need to use a better engine oil. At present I think it is a 15W-50, but not synthetic.

Edited by twr7cx

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That's true about the front fender. Get as much airflow over those fins mate.

I have had good results from semi synthetic and mineral oil in my own xr250.

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Two other thoughts:

 

1. Do you have a XR front fender? A fender from a water cooled bike will block air flow to the engine.

 

2. Use a high quality synthetic oil of at least xx-50, some Harley oils are available in that range. 

 

I too am a bit worried about my big bore 250 once summer comes.  I have a Wiseco 277 kit, 10.5:1 compression.  I was considering the big fin conversion, apparently XRs Onlys still does them.  Who has the conversion and is it worth it?  Cost?  And I am already running Amsoil 10W50 Dirt Bike Synthetic.  I was also considering one of the XRs Only dipsticks with a temp gauge integral.

Edited by cjjeepercreeper

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 I was also considering one of the XRs Only dipsticks with a temp gauge integral.

 

That's a good idea. I also recommend the Two2Cool oil additive.

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That's a good idea. I also recommend the Two2Cool oil additive.

 

I wonder how that would be since I am already using 10W50 Amsoil.  Are you using a synthetic oil with it.

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I wonder how that would be since I am already using 10W50 Amsoil.  Are you using a synthetic oil with it.

 

Yes. I've always run a full synth in my big bore 440. But I would still get the smell of hot, burning oil coming from the crankcase vent. After some research, I found it was from oil film that is coating the internals developing tiny bubbles/foam due to extreme heat. A film of bubbles/foam on your engine internals isn't lubricating and it's not conducting away heat to be carried away to the oil cooler. The Two2Cool prevents the oil from bubbling/foaming due to extreme heat.

 

I'd say it also sort of acts like a surfactant for oil, much like Dawn does for dishwater and Redline Water Wetter does for a bikes liquid cooling system. They all break the surface tension of the liquid they're added to, so they coat the surfaces they contact better, instead of having a tendancy to bead up.

 

It has been a major contributor in dropping my oil temps back to pre 440 kit levels.

 

If you're still running the stock spark plug with your big bore, you might also consider running a 1 step cooler plug.

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Besides running a JASO-MA compatable synthetic I suggest installing a XRsOnly oil temp dipstick, then you will know if you have a high oil temp issue.

I have one on my XR and I was disappointed on the cool oil temps.   :banghead: 

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On my 440 in the summer, my temps were hitting 250* and over. Too hot. I've got it back down to 225*. These readings are with the XRsOnly oil temp dipstick.

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