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01 650R Auxillary cooling question

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Looking for any ideas out there in Thumper land on how to keep my bike on the cooler side.  I really don't believe that my bike has a cooling issue when riding fast, but I am tending to slow it down a little and that means less airflow through the radiators. Its a dual sport setup and I will be going on multiple day rides.  I have looked into coolant additives, in line cooling fin things, and was even thinking  I could add a small electric fan on each radiator and just run them manually or with a t-stat set up???

 

Any ideas would be appreciated.

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Hi bigdawg

I ran a 650r for many miles as a dualsport, some gnarly off road stuff thrown in, I weigh 240lbs and never had overheating issues.

Are you jetted correctly, are the radiators clear and are you running 50% coolant mix? All of these are much easier than a fan, if you do choose a fan(not easy) you only need one on the right side, the radiator even has useful tabs to mount the fan.

Great bike!

Cheers

Steven

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Add a fan and they make kits for that bike. I had a supermoto 650r and never had an issue with overheating. Even sitting at stop lights for a couple of minutes in city traffic on 90f+ days.

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Hey Steven,

yes all those items are checked and good.

The only time I experienced an overheating issue was riding with my son up a pretty long uphill rutty grade and I wanted to stay close by. It ended up that my top end was worn out, rings, piston, intake valves, and the motor is being rebuilt as I write this. So why only a fan on the right side?

Hey kan3,

Do you have a lead on where to purchase a fan kit or any other info?

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"Why the right side only?" A good question, that's the only side you see them on when installed on dirt bikes, it may have something to do with space or the fact that the water pump sucks from this side? Maybe someone knows for real?

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I found a great article on 4 strokes.com under Technical,Honda,xr650r radiator fan installation, cant seem to paste a link here but check it out.

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As far as the right side only goes... That's the one with the mounting tabs for the OEM accessory cooling fan. Because the two radiators are joined with top and bottom hoses they act as one. I'm assuming that your 650 is similar to my 250x in that the engine dumps into the left, and then the right feeds back to the water pump, causing the left to be slightly hotter. Thermal transfer becomes more efficient with a greater difference in temperature, so the left radiator will naturally cool better. The fan has a greater impact on the right because the differential is slightly lower.

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As far as the right side only goes... That's the one with the mounting tabs for the OEM accessory cooling fan. Because the two radiators are joined with top and bottom hoses they act as one. I'm assuming that your 650 is similar to my 250x in that the engine dumps into the left, and then the right feeds back to the water pump, causing the left to be slightly hotter. Thermal transfer becomes more efficient with a greater difference in temperature, so the left radiator will naturally cool better. The fan has a greater impact on the right because the differential is slightly lower.

 

The fan would have a greater effect on the left side because it is in fact hotter and does in fact transfer heat faster.  Don't forget, temperature and heat are not the same thing.  You are trying to remove heat from the engine in order to maintain temperature.  It does not matter the temperature of the water entering the engine as long as you are in control of the temperature leaving the engine.

Edited by 1987CR250R

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