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I have been researching off and on for the last couple of months of how to get my VFR to run cooler in stop and go traffic. The highest it reach was 239F on the gauge cluster. 

I have found a couple of options in the forum, 

 

1. run a reverse fan blade from an RC51

 

2. install a higher CFM SPAL fan, although I couldnt figure out what size fan to run

 

3. Install slight larger radiators from a 6th gen

 

4. Install a custom front mount radiator from a Suzuki TL1000R

 

Right now I am like options 2, as I have run spal fans in the past without any issues on both bikes and cars. Or maybe a combination of option 2 and 3. Does anyone know what size fan would fit, a spal 5.5" or so? Also any input on any of the other options is very much appreciated.

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I'll try to find a low watt second fan that pushes air from the inside or pulls from the outside, and a temp switch tuned for 90 to 95° celsius

 

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Nothing will stop the 5th gen running hot in traffic.

Some things help, but only mrginally.

I have the 6th gen right side radiator, and the fan overide switch.

Left side radiator is doable, but not without lots of mods.

TLR radiator, I can't see how you could get it to fit.

Same for right side radiator fan, not easy.

My opinion is best bang for buck was the overide switch.

I will try reverse fan blade if I find one, but not expecting much.

Last time I swapped with my mates CBR1100XX on a hot day, his bike was running just as hot as mine.

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I've done the tlr rad, and it works really well. No idea if it fits under fairings; mines a fighter.

The  VTR fan worked ok, but the TLR rad was much better.

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ok, so no one has tried the spal fan so far?

 

keef, do you happen to have the dimension of the TLR radiator, and do you have pictures of the finished install?

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The spal fan as far as I understand,  has been done along with a lot of other things.   Bottom line, with out a lot of redoing and fitment issues none are much help by the sounds of it.  just don't go slow. but something tells me it wasn't a big enough deal for Honda to re do this.  but ah,   they did on the 8th gen didn't they.

 

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I've been riding an F6B around all week. It's got side rads and fans that pull from the side and push the air out the front. Exactly like the 5th Gen, except for the second fan. Biggest difference is an analog temp gauge. I bet if your bike was showing the needle near the top of the "normal" range you wouldn't give it second thought, but seeing that exact readout on the display makes us focus on the temp. 

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1 hour ago, KevCarver said:

I've been riding an F6B around all week. It's got side rads and fans that pull from the side and push the air out the front. Exactly like the 5th Gen, except for the second fan. Biggest difference is an analog temp gauge. I bet if your bike was showing the needle near the top of the "normal" range you wouldn't give it second thought, but seeing that exact readout on the display makes us focus on the temp. 

 

while that may be true, 239 degrees F is hot for any gas engine.

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Yeah saw my 98 at 245 a couple times. Suspect it now has a cracked head. 

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If you're seeing 239, I think you need a major clean out/new thermostat. 

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15 hours ago, fonque said:

ok, so no one has tried the spal fan so far?

 

keef, do you happen to have the dimension of the TLR radiator, and do you have pictures of the finished install?

heres my thread

 

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On 5/19/2017 at 1:46 AM, VFROZ said:

Nothing will stop the 5th gen running hot in traffic.

Some things help, but only mrginally.

I have the 6th gen right side radiator, and the fan overide switch.

Left side radiator is doable, but not without lots of mods.

TLR radiator, I can't see how you could get it to fit.

Same for right side radiator fan, not easy.

My opinion is best bang for buck was the overide switch.

I will try reverse fan blade if I find one, but not expecting much.

Last time I swapped with my mates CBR1100XX on a hot day, his bike was running just as hot as mine.

 

Installation of a fan override switch solved most of my cooling issues.  It takes some presence of mind to be on top of it but if I am it prevents things from getting out of hand. 

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Installation of a fan override switch solved most of my cooling issues.  It takes some presence of mind to be on top of it but if I am it prevents things from getting out of hand. 

And is the cheapest mod to make about this.

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I believe it's the owners guide that says 250F and up is a problem. I've seen the low 230's.

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Yes the owner's manual states 122C as a maximum (252F) beyond which serious engine damage can occur.

 

Just a question (maybe a dumb one) regarding changing the airflow direction, why is a reverse blade required. Surely the fan is powered by a DC motor, and reversing  the rotation would be as easy as swapping the polarity of the wires?

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Surely the fan is powered by a DC motor, and reversing  the rotation would be as easy as swapping the polarity of the wires?

Yes but dc motors could be designed to rotate in one direction (better) than in reverse.
This was discussed on another thread, but i can't find it now.
I don't know if it was a bearing related issue, that could end on blades hitting the radiator or what, but there was a reason to swap blades instead of reversing the polarity

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The reason not to simply reverse DC polarity and thus reverse the direction of rotation of a fan blade is actually an aerodynamic one. The most important feature of most motorcycles' fanblades is their airfoil shape - the curve of the blade from leading edge to trailing edge. This curve achieves greater flow at a given rotation speed through Bernoulli effect. 'Lift' occurs with low pressure on the convex side of the blade and high pressure on the concave side. Rotating the fan in the opposite direction would actually reverse this gain in flow - even less lift than flat blades would be generated. Flat blades would function in a more Newtonian manner, like paddles rather than wings.

 

It's not directly related to flow, but it is interesting to note that the angle of attack also varies from the hub to the outer 'tip' of the blades. This is because the blade's linear speed is slower at the hub. The blades have greater pitch or angle of attack at the hub than they do at the outer end of the blade in order for the entire fan to flow air at nearly the same rate across its area.

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A 1998 VFR800 is 19 years old now.  Wondering about the condition of the water pump impeller?  Any loss in efficiency at the water pump would be a problem in the overall heat-rejection equation.  How quickly and how often each little molecule of coolant circulates through the engine and then through the cooling system make a big difference.

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I bought the spal 5.2" pusher fan from amazon. I am going to give my radiators a thorough cleaning and install the new fan. If that doesnt work, then I will look into replacing the water pump. As a last resort I will retrofit a front mount radiator.

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Make sure you post pictures.

I'm interested to see if its any better then the stock fan.

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On 5/21/2017 at 9:13 PM, MaxSwell said:

I believe it's the owners guide that says 250F and up is a problem. I've seen the low 230's.

It starts flashing and will even change from air temp to engine temp after 122C (just above 251F).

 

Any idea at what temperature the fans actually kick on?

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The fan should kick in around 215-220.

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Typically 104-106°C

You don't want it to get so high it's flashing. That is a critical warning. I believe the bike shuts down over 125°C but cannot confirm that is true.

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