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Tired Of Having A Hot Vfr?

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Well the 2000 and 1997's use the same fan blade part #'s (67875-001)....Hmmm........? I wonder if it the VTR fan blade 19020-MBB-003 will help my Gen 4 / 97.......................?

Gen 4 Radiator

Gen 5 Radiator

I'm thinking no cause the fan on my 97 faces forward compared to the side on 2000. Anyone have two cents to offer on this?

The other part of that Joe is that on your 94 the correct all the time flow of air is in from the front, through the rad and out through the fan.

having your fan run in a sucker configuration there is in the same flow as if it was au natureal.

on the later versions using a sucker blade is counter to the natural flow and causes issues.

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Ya datz what I was thinkin. Or I could flip the VTR blades and they would work better then my originals is more my idea on this possible Gen4 mod. I'm just not sure if they will still fit or how much better the air flow is.

Edited by Joe Foe from Buffalo

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Warming an old thread ;)

I have the same problems with my RC36 I (3rd Gen?), has anyone tried if the fan fits 3rd Gen VFRs?

According to an online part catalogue, the 3rd Gen fan seems to be the same as most CBRs and later VFRs have.

But the RC51 fan seems to fit only SPs.

Can you help?

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Warming an old thread ;)

I have the same problems with my RC36 I (3rd Gen?), has anyone tried if the fan fits 3rd Gen VFRs?

According to an online part catalogue, the 3rd Gen fan seems to be the same as most CBRs and later VFRs have.

But the RC51 fan seems to fit only SPs.

Can you help?

The vtr fan works only on the side-mounted radiators on later VFRs. Stock set up pulls air in from the left side (only), which is insufficient, while the vtr fan REVERSES the air flow through the left-side radiator, PUSHING it out the left side after drawing it through the rest of the fairing/engine area.

If your bike's radiator is in FRONT rather than on the SIDE, then using the vtr fan will cause your bike to overheat.

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Warming an old thread ;)

I have the same problems with my RC36 I (3rd Gen?), has anyone tried if the fan fits 3rd Gen VFRs?

According to an online part catalogue, the 3rd Gen fan seems to be the same as most CBRs and later VFRs have.

But the RC51 fan seems to fit only SPs.

Can you help?

3rd gen running hot?? that's strange cause I thought 3rd and 4th gens actually run cool engine temp-wise.

There must be something else wrong with your cooling system.

Many wondered why Honda went with side radiators in the first place as ti seems like it would logically reulst in hotter runnging bikes, as the cooling airflow is not as direct as with cinventional front mounted radiators. Honda seems to have compunded the problem by reversing the way the cooling fans work by pulling in air from the side of the bike instead of out, which seems to result in heat saturation around the engine because the hot air in the fairing does not have an easy way out.. The earlier gen VFRs do not have this problem as they have conventional front mounted rads that pull the air through the front and out the sides of the bike easily. Only heat problems I know on the 3rd gen is how your right ankle can get very hot because of the pipes running next to the right rearset. but that's mostly with riding in slow speeds in very hot weather too.

Honda seems to have finally gotten the message on their side mounted radiator concept. Note that they had abandoned it with the 1200. I haven't heard of any hot running issues with the new bike yet.

Beck

95 VFR

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I have not read the entire post yet.

Which way does your car fan run? Does it pull cooler air toward the engine or does it blow hot air from the engine to the cooler ambient air outside of the car?

Bikes are not diesel trucks ,the small capacity of a bikes cooling system are not made to cope with the traffic conditions that we find ourselves in.

While running in St.Louis traffic last summer my temps got toward the 220-227 range before the fan kicked on and brought the temps down. I was freaked out!!! The bike had never gotten that hot before and I usually ride and live close to Mexico.

Long traffic jams(we got them) I find the shade of an overpass and shut her down or run down the shoulder to cool (myself).Austin and San Antonio have jams were you do not move for 30 minutes or more in a 100 *f.

In those conditions I do not keep my cool ,either.

Just saying it seems to me that your cooling system seems to have something not functioning properly rather than the direction of your fan blades.

Sorry if this has already been covered.

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The fan is dsigned to keep the heat off the rider, it works really well if the bike is working as it should. If your sitting in 100 degree traffic, at 223 degrees, the fan should kick in and take temp to the lower 200.s . I find the fan very effective sitting in traffic in its ability to drop the heat. But 100 degree in san antone or Austin will be hot no matter.

Turn the fan the other way, the Hot air will be hitting you in the face

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I have not read the entire post yet.

Which way does your car fan run? Does it pull cooler air toward the engine or does it blow hot air from the engine to the cooler ambient air outside of the car?

Bikes are not diesel trucks ,the small capacity of a bikes cooling system are not made to cope with the traffic conditions that we find ourselves in.

Actually it matters not if the fan moves the air over the engine or not. What matters is that it draws the coolest air it can find across the fins of the radiator.

In you cars case the coolest air it can find is at the front of the vehicle.

The coolest air that both radiators can find on the VFR is still at the front of the bike. What happens when the oem sucker fan runs is that it pulls air from the left side of the bike, heats it with the left rad and then heats it again with the engine & header then pushes it out the front of the bike. The right side rad gets next to no flow and what it does get is already much hotter than ambient so the right rad just becomes a heat mass, not a heat sink.

The fan is dsigned to keep the heat off the rider, it works really well if the bike is working as it should. If your sitting in 100 degree traffic, at 223 degrees, the fan should kick in and take temp to the lower 200.s . I find the fan very effective sitting in traffic in its ability to drop the heat. But 100 degree in san antone or Austin will be hot no matter.

Turn the fan the other way, the Hot air will be hitting you in the face

I don't find it hitting me in the face. It used to rise up around the triples and bake both my hands, but now only my left calf and my left elbow get warm. I'd rather put up with that instead of overheating my motor.

In fact the only issue I still have with the heat on the VFR is that if I'm really stuck in hot traffic, the bike will go into the state where the fan constantly runs.

I think I may make some sort of extractor duct to make sure that all the heated air from the rads is ejected to the atmosphere and none can find a stagnant spot behind the fairing.

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Cool deal on the Fan mods, but its not the problem. The stock fan is adequate, but the coolant isnt. The problem you it is the temp suddenly surges p and won come down till you get some serious air and water moving in there.

Ok, so what you really have ( and there is an old thread around here somewhere we hashed it out)is a localized boiling issue in the head area. Whe the water boils on the metal it stops cooln well as the forming steam insulates it from the water. Think of a really hot fry pan, drop water on, the drop just glides around for a long time. If the pan is a bit less hot, the drop of water sticks, tansfers heat efficiently andnthen evaporates.

My last landlord is an old indy racer and sells automotive chemicals. Red line, justice brothers, etc... I tell him about it and he hands me two bottles.

One was a cooling system protectant, so no corrosion issues. The other was a wetting agent, calld JB Cool. I added them into an empty coolin sys with bottled water.

Solved. The 99% water mix is better than with coolant, the protectant you just need, the cool helps increase the heatbtransfer from metal to liquid and does a good enough job thathe meal never gets critical hot in there.

If anybody wants some (their fuel injection cleaner is the bestnive ever used as well) you can look for a local JB guy or if nothing else i could help in shipping some out to you.

I can sit at idle now in the summer and the stock fan keeps it cool. Im sure the lack of a weird hot spot in the head has got to help the head in the long run.

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I have not read the entire post yet.

Which way does your car fan run? Does it pull cooler air toward the engine or does it blow hot air from the engine to the cooler ambient air outside of the car?

Bikes are not diesel trucks ,the small capacity of a bikes cooling system are not made to cope with the traffic conditions that we find ourselves in.

Actually it matters not if the fan moves the air over the engine or not. What matters is that it draws the coolest air it can find across the fins of the radiator.

In you cars case the coolest air it can find is at the front of the vehicle.

The coolest air that both radiators can find on the VFR is still at the front of the bike. What happens when the oem sucker fan runs is that it pulls air from the left side of the bike, heats it with the left rad and then heats it again with the engine & header then pushes it out the front of the bike. The right side rad gets next to no flow and what it does get is already much hotter than ambient so the right rad just becomes a heat mass, not a heat sink.

The fan is dsigned to keep the heat off the rider, it works really well if the bike is working as it should. If your sitting in 100 degree traffic, at 223 degrees, the fan should kick in and take temp to the lower 200.s . I find the fan very effective sitting in traffic in its ability to drop the heat. But 100 degree in san antone or Austin will be hot no matter.

Turn the fan the other way, the Hot air will be hitting you in the face

I don't find it hitting me in the face. It used to rise up around the triples and bake both my hands, but now only my left calf and my left elbow get warm. I'd rather put up with that instead of overheating my motor.

In fact the only issue I still have with the heat on the VFR is that if I'm really stuck in hot traffic, the bike will go into the state where the fan constantly runs.

I think I may make some sort of extractor duct to make sure that all the heated air from the rads is ejected to the atmosphere and none can find a stagnant spot behind the fairing.

Let's see here now... there is no problem when the bike's stationary... that's the whole point of this thread... the original hypothesis doesn't pose a stationary bike as a problem... nor the hot air being projected onto some part of the rider's anatomy.

The issue being dealt with is the unfortunate fact that when in motion, the stock configuration creates a flow of air in direct opposition to the natural air flowing in the front of the bike in such a way that the cooling system is unable to perform its function effectively... so much so that eventually, if these conditions continue (for example traffic or road conditions that do not allow one to ride at more than approx. 80 km/h, or stop and go traffic, etc), the cooling system enters into a loop whereby the bike slowly gets hotter and hotter, the fan stays on for longer and longer... and this puts the charging system (battery, R/R, stator and wiring harness), and the fan's motor, under continuing stress.

This tends to be a problem moreso in areas with relatively high ambient temps... or city riding (not something the VFR was really meant for I guess).

The fan is efficient enough when the bike is stopped... but who tends to only have the fan click into operation when they're stopped??

I have done some serious testing of both OEM fan blades and VTR fan blades in varying conditions to see what effects are achieved in the real world application.

The stock blades are much more efficient when stopped or at such slow speeds that the naturally incoming air from the foreward movement of the bike doesn't overwhelm the force of the fan. Considerably more efficient. Apparently this has something to do with it being more effective to pull a load than to push it, against some resistence like friction (in this case the radiator fins).

When in motion between say, 20 km/h to 80 km/h... the OEM fan is rendered useless... and this is possibly when one most needs the fan to be effective.

At speeds above 80 km/h... the force of the naturally incoming air overcomes the stock fan's airflow and the bike starts to cool down... this can take considerable time if the bike has already heated up big time with the fan constantly coming on... it also will not do much good for the fan's motor... fighting against this antagonistic force...

The VTR's fan blades are less efficient with the bike stationary. At least on my 5th gen, after several cycles of heating and cooling (104 - 96 - 104 - 96 - 104ºC), the fan was no longer able to cool the bike to below the cut-off temp... (96ºC)... and the fan would just stay on... after several more cycles, the fan would cut out without having managed to drop the temp... as if it had just given up.

I have seen the temp display start to blink (121ºC) only once. Apparently the bike shuts down at 125ºC.

This was with the stock fan with some very spirited riding in a very hot climate. I of course immediately pulled over and turned off the bike.

The VTR blades are infinitely more efficient when in foreward motion as the airflow they create is complemented by the naturally incoming air from up front...

You will only notice the hot air when your stopped (at the lights for example)... just as you do with the stock fan... but on a different part of your body.

If you tend to spend a lot of time with the motor running but the bike stationary, then don't do this mod!!

I end with an enigma: Isn't it funny how stators and R/R's fry in the hot months of the year???

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Your exactly right, im not argueing that thats whats happening, and you dd a really nice job of explaining and documenting it as well.

To simplify it, you have a reduced dumping of thermal energy at low forward speeds due to the fan 'fighting' the air moving across the bike. So the coolant has to be at a higher temp to dump heat. It does dump some heat or the engine would go into runaway overheat, just not enough.

When the coolant gets that extra bit hot though is when you start getting hot spots in the head.

So it does still cool the motor under that condition but not enough. My answer is simply to add a bit of increased efficiency to the whole cooling system ( maybe 10%?) and then it has sufficient capacity to deal with the condition of reduced air flow. I can ride slow speeds up steep hills for long periods of tme now in the dead of summer. I live on a mountain served by a 2 lane road that ALSO leads to a damn tourist destination, so i encounter this a lot.

Answers like more air fliw over the radiator increases its efficiency, a higher pressure cap raises the boiling point and the higher delta temp relative to ambiant also increases its efficiency in dumping btu's. I just thought about tbe problem in a lazy way as i wanted to be riding and not reinventing my fan ( i did think about it, it was my next option if the chemicals weren enough of an increase) as in " whats the easiest way to get a bit more efficiency in the cooling system"

Its just a much cheaper easier mod. The runaway head temp thing i used to get at idle too. It ould get to about 195f, then spike to 225 and not come down untill i rode 5 min over 30 mph or shut the bike down for 2 minutes. Both were annoying.

When i finally get my torocharger, ill probably do the fan mod too...

Now no longer need to worry about my cooling system, it just works like it should have from the factory.

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The stock blades are much more efficient when stopped or at such slow speeds that the naturally incoming air from the foreward movement of the bike doesn't overwhelm the force of the fan. Considerably more efficient. Apparently this has something to do with it being more effective to pull a load than to push it, against some resistence like friction (in this case the radiator fins).

I think what you're seeing is due to the temperature of the air being forced over the radiator not whether that air is pushed or pulled. In stock configuration the fan pulls cool (relatively speaking) air from outside over the radiator and exhausts it into the engine compartment. The VTR reverses the direction of airflow, forcing superheated air from inside the engine compartment through the radiator. The delta T between engine compartment air and the radiator is much narrower than that between outside air and the radiator. Therefore, the VTR arrangement results in less heat transfered from the water to the air and less efficient cooling than the stock set up. I suspect that's exactly the reason the engineers designed it as they did.

Once you're rolling all this changes. Now you have a supply of cooler air being introduced from the front and the fan is an active impediment to that air getting through the left radiator and while at the same time the fan is unable to draw air from the outside. The right radiator is unaffected, so the engine's still able to shed heat, but not enough because you've lost 40 to 50% of your cooling capacity. Some time back, some folks had success with a manual override to turn on the fan and also turn it OFF in exactly the situation we're talking about.

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The stock blades are much more efficient when stopped or at such slow speeds that the naturally incoming air from the foreward movement of the bike doesn't overwhelm the force of the fan. Considerably more efficient. Apparently this has something to do with it being more effective to pull a load than to push it, against some resistence like friction (in this case the radiator fins).

I think what you're seeing is due to the temperature of the air being forced over the radiator not whether that air is pushed or pulled. In stock configuration the fan pulls cool (relatively speaking) air from outside over the radiator and exhausts it into the engine compartment. The VTR reverses the direction of airflow, forcing superheated air from inside the engine compartment through the radiator. The delta T between engine compartment air and the radiator is much narrower than that between outside air and the radiator. Therefore, the VTR arrangement results in less heat transfered from the water to the air and less efficient cooling than the stock set up. I suspect that's exactly the reason the engineers designed it as they did.

Once you're rolling all this changes. Now you have a supply of cooler air being introduced from the front and the fan is an active impediment to that air getting through the left radiator and while at the same time the fan is unable to draw air from the outside. The right radiator is unaffected, so the engine's still able to shed heat, but not enough because you've lost 40 to 50% of your cooling capacity. Some time back, some folks had success with a manual override to turn on the fan and also turn it OFF in exactly the situation we're talking about.

Exactly... forgot to mention that point... of course it ahs a big influence on the lower effectiveness of the VTR blades when the bike is stationary... it's forcing much hotter air through the rad...

And yes... the option to turn the fan off manually when forward motion coincides with the fan coming on is an excellent idea, except for those who tend to leave tings like irons or ovens on... :laughing6-hehe:

Wouldn't be a bad idea to be able to manually force the fan ON for certain situations as well!!

and if I could just find a 8x8 cm fan that produced a decent airflow for the RHS rad... there ain't room for much more... :happy:

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Your exactly right, im not argueing that thats whats happening, and you dd a really nice job of explaining and documenting it as well.

To simplify it, you have a reduced dumping of thermal energy at low forward speeds due to the fan 'fighting' the air moving across the bike. So the coolant has to be at a higher temp to dump heat. It does dump some heat or the engine would go into runaway overheat, just not enough.

When the coolant gets that extra bit hot though is when you start getting hot spots in the head.

So it does still cool the motor under that condition but not enough. My answer is simply to add a bit of increased efficiency to the whole cooling system ( maybe 10%?) and then it has sufficient capacity to deal with the condition of reduced air flow. I can ride slow speeds up steep hills for long periods of tme now in the dead of summer. I live on a mountain served by a 2 lane road that ALSO leads to a damn tourist destination, so i encounter this a lot.

Answers like more air fliw over the radiator increases its efficiency, a higher pressure cap raises the boiling point and the higher delta temp relative to ambiant also increases its efficiency in dumping btu's. I just thought about tbe problem in a lazy way as i wanted to be riding and not reinventing my fan ( i did think about it, it was my next option if the chemicals weren enough of an increase) as in " whats the easiest way to get a bit more efficiency in the cooling system"

Its just a much cheaper easier mod. The runaway head temp thing i used to get at idle too. It ould get to about 195f, then spike to 225 and not come down untill i rode 5 min over 30 mph or shut the bike down for 2 minutes. Both were annoying.

When i finally get my torocharger, ill probably do the fan mod too...

Now no longer need to worry about my cooling system, it just works like it should have from the factory.

I'm sure you have no commercial interest in promoting these products so I'm sure it must be true... maybe I should seriously consider trying them out..

did a quick search on the net for JB Cool and no go... (I'm in Spain so there won't be a local JB guy)

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So how does one tell just by looking at the read-out that the bike is overheating? My Y2K with 38K has never had any warning light come on or flash even when temps reached 235 F. What I did notice before I installed a new thermostat was that the temp values seldom returned to below 200 regardless of how fast I was running. Even with a new thermostat, temperatures still reach the 230's when I'm climbing very twisty grades in 1st or 2nd gear. Once over the top of the grade and on the downside, temps drop back in the 180's. May take a while but it happens. However, the VTR fan replacement does sound like a good idea. Thanks for the info.

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Have to agree with Auspanol - my experience with the stock fan and VTR fan is:

Stock fan

- stationary - ok, pass

- low speed moving - fail

VTR fan

- stationary - fail

- low speed and up moving - strong pass

Bleah, pick your poison.... :comp13:

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I just spent a bunch of time in traffic with the mod. It was about 75 derees f ambient.

It was hot having that air blowing on me. I may go back to stock. It was that bad.

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I'm waiting for Tightwad to come up with an rig that will tap into the speed sensor and turn the fan off when road speed gets above 15-20 mph.:comp13:

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I'm waiting for Tightwad to come up with an rig that will tap into the speed sensor and turn the fan off when road speed gets above 15-20 mph.:comp13:

Careful on that one, with the fan diabled and a tailwind ( happened to me in vegas) you get a zero airflow condition.

I used to sell the JB stuff, i can still get it but they have agreements about you van only sell your assigned area. Mailing it out is a no no, but i dont work for them anymore. They are popular in hot rod stuff, and thats theyre main market. Hot rod magazine has done a bunch of heads up testing on a dyno and it always wins.

Redline Water Wetter is similiar, but you still need an anti corrosive and lubricant to go with it. Getting rid of the antifreeze alone gives you more cooling power, adding a proper surfactant like the redline or jb cool is even better. Do worry about freezing though, you lose that protection. If i remeber right, a 50/50 mix of ethelyne glycol is like 80% of the cooling power of straight water, propalyne glycol is a bit worse again.

I used to fix check engine lights in GM cars with it when they couldnt figure out the problem. Short version, your coolant goes acidic eventually and the dissimiliar metals in your cooling system turn into a slight battery. Stick your multimeter to ground and in your radiator fluid and see if you read dc voltage. The anti corrosive turns it to neutral PH, no voltage generated, and your sensors on your engine stop reading false voltages.

http://justicebrothers.com/pages/products/products_carcare_radiator_additives.htm

All their stuff is really better than 99% of everything else out there, they had a genius chemist years ago who formulated everything they have.

Is there room on the second radiator to run a fan blowing opposite the first? Then therenis always airflow over a radiator under any condition... I dont remember how much room is in there, ,its been a while since i unwrapped the plastics off it.

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I'm waiting for Tightwad to come up with an rig that will tap into the speed sensor and turn the fan off when road speed gets above 15-20 mph.:comp13:

Careful on that one, with the fan diabled and a tailwind ( happened to me in vegas) you get a zero airflow condition.

Is there room on the second radiator to run a fan blowing opposite the first? Then therenis always airflow over a radiator under any condition... I dont remember how much room is in there, ,its been a while since i unwrapped the plastics off it.

I'm sure there is no room on the right side radiator for an extra fan, if there was there are at least 50 of us geek fooles who would have tried to fit one.

- I think on the 5th gen, if you are in hot climates, going to a 3 row oil cooler from the stocker 2 row is a good idea and would help. Veefer800Canuck has done it.

- I was once in Arizona on a fly n ride and we were in the high plains with a strong tailwind. It was totally bizarre running at about 120 and feeling a wind like 40 mph in the face. Very eerie.....

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did a quick search on the net for JB Cool and no go... (I'm in Spain so there won't be a local JB guy)

Don't be so sure...JB says they have an "international distribution network", and JB is surprisingly big in the speedway and grass track world (Northern/Eastern Europe), so I'm sure there is a European distributor (if not a Spanish one). Never used their stuff myself, though.

Ciao,

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I dunno what you blokes are all on about. It can get mighty hot here in Australia, and the most I've ever seen on my temp gauge was 112 degrees sitting in traffic. When that stock fan comes on, it works - the temperature drops. Also, the engine does not pink when under load even in these hot temperatures.

Ergo, why bother changing? You should see the fan on a CBR1000RR - it's about 1/10th the size of the radiator, sitting in the top right corner. Guess what - it works too!

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There are all sorts of ways to raise the boiling temp of the coolant, but that doesn't solve the issue of running hot and eventually overheating.

There are coolants that can get way up past 300F without boiling, but that is not okay for a bike's engine.

That is why I'm investigating the cooling air flow and a fan blade to change it from the original plan.

By the way, the GL1800 have a similar "backwards" flowing fan and their owners all complained to Mother Honda about it. The GL1800's would overheat in parades and traffic.

Honda did something to resolve this but I don't remember what it was (except that it was not to change the fan design).

So the rc51, the VFR and GL1800's have these draw in fan designs and they also have low speed cooling issues.

coincidence???

You tell me.

Today was cooler than last week and I did not encounter much creeping traffic, so I cannot offer much useful test data. All I can say is that when I stopped the bike after commuting home and the temp rose to 224, the fan kicked in and the temp very quickly (compared to other times) started to come back down.

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