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Manual Fan Switch


Manny98

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Been looking at adding a manual rad fan switch to my 98' for awhile.  I was able to find the instructions a couple of months back but can't seem to find them now.

I've done this to my RC51 but it is a much simpler process as the RC has a fan switch relay.  Has anyone done this on a fifth generation?

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Link below to a prior thread on the subject.  5G or 6G, it's the same - the fan is controlled in the same way.  The only difference is where you decide to locate the switch.  Your main decision is a 2 or 3 position switch.  The 2 obviously is "normal ops" and the other position = "fan on".  After some runs down the highway after leaving stalled traffic I realized that the fan continued running while going down the highway because it never got the chance to cool it down before I got moving.  Once on, it stalls the airflow over the left rad so it just doesn't cool off until slowing down - no matter how fast you ride.  That's where the 3rd position comes in - it allows the fan to be forced off while running down the road.  Which ever type of switch you have, you have to have situational awareness of its position.  You'll only forget a time or two (wondering "WTF - WHY is this thing getting so hot???") before staying on top of it.  I think there's a diagram running around someplace of how to do it if needed. 

 

https://www.vfrdiscussion.com/index.php?/forums/topic/80201-override-switch-for-cooling-fan/

 

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not to thread-jack, but... I think it's worth addressing the unavoidable, engineered-in weakness that naturally comes as part of a "side-radiator" design.

 

This is something I've been thinking about for a long time (whenever I find myself thinking about how hot the VFR800 runs).

 

The built-in problem with side-radiators is you have to move coolant from one side of the bike to the other.  You have no choice but to run a large diameter tube full of coolant right past the headers for cylinders #2 and #4 (less than about 1.5 inches).  I don't know what the math of this situation is like, but you know there has to be substantial radiant heat-energy transfer in this area.

 

I've been thinking of putting heat protection on this coolant tube since I first rode my 5th Gen in summer heat.

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Can you install a "pusher" fan like I did on my RC51? It made a big difference, as now the fan, as well as forced air while riding are both going the same direction.

 

I don't have the wiring diagrams for your generation, but on the 3rd gen, if you simply ground the wire that goes to the fan, it will come on. So you would just have to tap into that wire, run it to a switch, then to ground. Whenever you want the fan on, just hit the switch.  If you want the 3-way as above, there will of course be more wiring.

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Single pole on/off switch is all that is really required, providing an additional ground path to the fan appart from the normal switched ground path via the Thermo Switch (splice into the Back wire from the Thermo Switch to the Fan Motor). See attached drawing.

The Switch positions could be called Normal or Auto and Override or On.

 

Another option is to use a Double pole on/off switch. One pole wired per above and the other pole used to Illuminate a warning light for the On/Override position when selected, hopefully meaning you won't leave the switch in the On/Override state forever!

Fan Switch Mod.pdf

 

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The heat up issue is not to do with the size of the cooler but with the airflow (or a lack of it). Unless you have air flowing through a cooler/radiator then the heat will just build up in the fluid no matter how big the item is.

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3 hours ago, Terry said:

The heat up issue is not to do with the size of the cooler but with the airflow (or a lack of it). Unless you have air flowing through a cooler/radiator then the heat will just build up in the fluid no matter how big the item is.

Theoretically Cooler is just simple heat exchanger. To increase heat transfer, forced convection is just one part of equation, increase of active surface is another. Oil cooler already has high delta T, higher than water radiator so it is quite effective. There are liter bikes entirely cooled by oil. So question is, do we have enough room?

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An air scoop could help with air flow over the oil cooler but if you try and make the mouth of the scoop too wide it will impact the front wheel fender when the front suspension goes into max compression, especially if you have dropped the triple tree by 8-9 mm for better steering. I tried this when I fitted an RC51 oil cooler on my 6 Gen but found it bottomed out on the fender on hard braking. Would love to increase air flow over the cooler as it would increase cooling especially as the oil has a higher temp than the coolant.

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There was once talk about fitting a different fan blade to one side of a 5th gen (to reverse the flow).  I don't recall which bike donated it, unfortunately, though I did go to the trouble of buying one at the time.  Might help?

 

Ciao,

 

JZH

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1 hour ago, JZH said:

There was once talk about fitting a different fan blade to one side of a 5th gen (to reverse the flow).  I don't recall which bike donated it, unfortunately, though I did go to the trouble of buying one at the time.  Might help?

 

Ciao,

 

JZH

 

I think it was the VTR1000F Superhawk.

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1 hour ago, Captain 80s said:

 

I think it was the VTR1000F Superhawk.

Yes, it's the Superhawk fan, I'm running one.

 

Somewhere back in the threads, was a mod adding 6th gen radiators to 5th gens.....

I seem to remember that the 6ths are 13% larger was stated in the thread.

Here in Ohio it, doesn't get over 90 degrees that often, so I haven't really needed to screw with hot running that much. Mbe if I lived farther south, that would be something to consider.....

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