Radiator Fan

[TurdEngineer99]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

[SEBSPEED]

1. Not sure if you'll have the space needed behind the rad to fit the fan(maybe, maybe not, as the front/rear cylinder banks are offset)

2. If you do have room, try to wire the 2nd fan so it doesn't kick on at the same time as the original, to cut the load demand

3. Good luck with it!

[CandyRedRC46]

sounds like a good idea in theory, (just like side mounted radiators). good luck finding room. id personally rather look into air ducts to better route air into the radiators...

[JES_VFR]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

First off I try doing the superhawk fan blade swap on the left side fan for a few reasons.

1. it really does work, keeping the temps under control.

2. there really isn't much room up in there for another fan. I had a small automotive one and it wouldn't fit. And even if it had fit, it would not have been very effective since it would end up blocking most of the air path with its bulk.

3. those fans draw a lot of amps (something like 50 amps to over come the stalled armature) when they kick in and continue to draw significant amps even after the fan is spun up (like 30 amps). do you really think that you can afford a second continuous 30 amp load, along with the second big startup spike???.

If that did not deter you, then I can only say this. Go out and source two good Pulse width modulating fan controllers with variable speed control, a thermo sensor and ramp-up function. Then when you install them both, Set the left side fan to some low value like 210 and the right hand fan at say 230. That way the second fan will only run when you get really hot and desperate.

to be honest, about the only changes I'd make to my VFR's setup if I could right now would be;

install one of those fan controllers and set the ramp up temperature for about 215 (that would start the fan spinning a little earlier and ramp up to full speed by 225),

install some stainless steel ducting to help keep fresh air from the front passing over the radiators, stopping heat soak from the cylinders,

Maybe add an extractor duct to give real seal from the outside of the radiator to the fairing.

those last two things would help with overall flow of the air across the radiators and make them more effective all the time.

[Serenity_VFR]

The Superhawk fan swap is the "hot" setup. Works for me. The thing just cools off regardless. No more watching the temps climb up when in walking-speed and stop&go traffic.

[serranot]

The Superhawk fan swap is the "hot" setup. Works for me. The thing just cools off regardless. No more watching the temps climb up when in walking-speed and stop&go traffic.

Do you swap the whole fan assembly or just the fan itself?

[kaldek]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

Be aware that the fan on the 6th-gen blows INWARDS, not outwards. This is because the fan is mainly required when you are in stop-go traffic, and sucking air from where it's hot (i.e. the engine) through the radiator would be bad, so it sucks it from the outside air to the inside. When you get moving, the airflow through the bike blows from the inside to the outside.

If you fit a second fan, you'll be wanting it to blow inwards too. Otherwise, you'll be adding heat to your cooling system, not taking it away.

And anyway, I've had my '02 for 8 years and done 130,000KM. I ride all year round in Australia, land of the 110 degree summer. My bike's never overheated. Why the desire for a 2nd fan?

[marid2apterbilt]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

Be aware that the fan on the 6th-gen blows INWARDS, not outwards.

They must have changed this for the newer 6th gens as I do belive mine blows outward (2006)

[JES_VFR]

The Superhawk fan swap is the "hot" setup. Works for me. The thing just cools off regardless. No more watching the temps climb up when in walking-speed and stop&go traffic.

Do you swap the whole fan assembly or just the fan itself?

Just the blade, that changes the fan from a tractor (that pulls the air inward through the rad core) to a pusher (that pushes the air our through the core).

[JES_VFR]

Be aware that the fan on the 6th-gen blows INWARDS, not outwards. This is because the fan is mainly required when you are in stop-go traffic, and sucking air from where it's hot (i.e. the engine) through the radiator would be bad, so it sucks it from the outside air to the inside. When you get moving, the airflow through the bike blows from the inside to the outside.

If you fit a second fan, you'll be wanting it to blow inwards too. Otherwise, you'll be adding heat to your cooling system, not taking it away.

And anyway, I've had my '02 for 8 years and done 130,000KM. I ride all year round in Australia, land of the 110 degree summer. My bike's never overheated. Why the desire for a 2nd fan?

Honda's lets suck the heat back in fans have proven to be crap.

I currently have two honda's that came with tractor fans on the side mounted radiators. Both bikes would just bake in stop and go traffic. The fans were worse than useless on hot days (95F and 90%+ plus humidity) as once the kicked on in traffic, they pretty much ran until you got out of the traffic and back up to speed or bailed out with the bike nearly overheating (i saw 255 a couple of times in philadelphia traffic). Even when you got moving again, the bike had to get moving up over 35mph or the fans just screwed things up worse.

I have reversed the fan air flow on both my VFR and my RC51. Now either bike will handle even seam sealer melting heat AND wet blanket smothering Humidity without overheating.

If I was serious about fitting a second fan on the VFR, I fit one that blows out and install the superhawk fan blade on the original fan.

Then the heat will blow out of the engine bay, not just keep circulating around getting hotter and hotter.

[JES_VFR]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

Be aware that the fan on the 6th-gen blows INWARDS, not outwards.

They must have changed this for the newer 6th gens as I do belive mine blows outward (2006)

I'd check as Ron Ayers lists the same fan blade for both 2002 and 2006 bikes.

And these blades are not very efficient if you just reverse the polarity of the motor leads.

you need to change the blade to make it work as a pusher fan.

Check you fan direction with a piece of paper.

run the bike until the fan kicks on, the paper will cling to the radiator that you can reach through the vent then it is a tractor. If the paper keeps tying to blow out of the vent, then its a pusher.

[kaldek]

Honda's lets suck the heat back in fans have proven to be crap.

I currently have two honda's that came with tractor fans on the side mounted radiators. Both bikes would just bake in stop and go traffic. The fans were worse than useless on hot days (95F and 90%+ plus humidity) as once the kicked on in traffic, they pretty much ran until you got out of the traffic and back up to speed or bailed out with the bike nearly overheating (i saw 255 a couple of times in philadelphia traffic). Even when you got moving again, the bike had to get moving up over 35mph or the fans just screwed things up worse.

I have reversed the fan air flow on both my VFR and my RC51. Now either bike will handle even seam sealer melting heat AND wet blanket smothering Humidity without overheating.

I've never had an overheating problem. We had a 47 degree day here recently (117 degrees fahrenheit) and the bike coped fine. Stop-go traffic too.

If it's so crap, why did Honda do it in first place. Please, no comparisons to flapper valves, VTEC, or cam chains. Gimme something better than THAT, puh-leeez!

[spud786]

We all know about side mounted radiators not being very efficient with exchanging heat. The left side rad. has a fan and the right side doesnt. As I am parting out my old Ducati, I have another radiator fan on hand and was thinking of fabricating a bracket and modifying the wiring so that 2 fans can run in parallel when commanded on/off.

Anyone ever try this or have ideas or advice to share? Was also thinking also the R/R wouldn't mind the extra amperage load.

The vfr design is to keep heat off the rider, works great to me. You mean averaging 210 degree water temps in the heat?

I would like to see an avege of no more than 200 degree avegage on water temp in high heat. I will be running a test in the next 30 days.

The normal range for a vfr is from 170 degree to 225 and no boil over issues, thats the way a vfr is supposed to work, and thats been my result.

[JES_VFR]

I've never had an overheating problem. We had a 47 degree day here recently (117 degrees fahrenheit) and the bike coped fine. Stop-go traffic too.

If it's so crap, why did Honda do it in first place. Please, no comparisons to flapper valves, VTEC, or cam chains. Gimme something better than THAT, puh-leeez!

Well I have a couple of questions for you on your hot day.

1. What was the humidity? As the heat index effects the engines ability to cool as well. If you look at this table NOAA heat index, you can see how much the humidity effects things. Around here through June/July/August and into September the humidity and temperature regularly push us into the extreme danger zone past where they even list an equivalent temperature. Especially in stop and go traffic in the afternoon. I've seen huge thunderstorms blow up and dump everything on stopped traffic and you can just watch the steam rise off the pavement, while the rain is still falling.

2. How long were standing dead still? How long did it take you to move a Km at the slowest point?

The answers around here are stopped dead in traffic for twenty minutes or more sometimes and Half an hour to go roughly a KM.

Its all clutch just about out, back to the bar and wait crap.. Now no bike or car likes this kind of operating conditions, but other bikes I've ridden in these conditions get hot, the fan comes on and the temperature stabilizes until I can get moving again. The VFR before the fan swap, would come on and the temps would just keep going, I'd frequently end up cutting the motor at 245 and paddling the bike along with my feet, until it cooled off a bit. I'd even gotten pretty good at bumping the bike, so that the fan wouldn't kill the battery before I could start the hot engine with its heat soaked starter. These oem's should forget doing heat durability testing in the open desert, they should have to do it in some downtown area (Baltimore MD, Wilmington DE, Philadelphia PA, the rt42 & RT 55 interchange in NJ). All these spots are parking lots in the summer heat and humidity just about every rush hour all summer long (and forget friday nights).

Anyway, those are the conditions that my vehicles have to survive some do it well right from the factory, some can't hack it without help. Lately most newer vehicles have all needed help with the cooling in traffic issues.

Now why did Honda design so many of their bikes with suck fans instead of blow ones?

Well I don't know what the biggest reasons were, but I have heard a few reasons.

1. Pulling the air inward keeps the exhausted heat from baking the riders leg (and possibly arms). Instead it makes the whole bike hot enough to roast all of the riders anatomy.

2. Its supposedly quieter, which it might just be. But I would think that three or four minutes of a slightly louder fan running would be better for everyone's health, than the constant running fan and the heat altered emissions (the NOx emissions that everyone is paranoid about around here can be easily cut back by just cooling the intake air and exhaust).

3. Supposedly its more efficient since the fans in suck mode draw cooler external air through the radiator core and push it out the right side. Unfortunately that doesn't work when moving slowly or stopped. The fan sucks air in one side, them pushes it in to the heated space around the engine and it never gets out, the right hand side. Even on the RC51 with its two fans, the heat just built up, since the only place it had to go is up around the frame, triples and tank. The bars would reach, burn you hands hot quickly in traffic before I reversed the airflow.

I just get the feeling that Mother Honda did not do enough real world testing of the fan designs for handling traffic induced heat soak conditions.

I can tell you this, the GL1800 debuted with a tractor fan, but after a couple of years and lots of complaints from owners all over the world, Honda changed the fan blade to a pusher style unit to cure the cooling issues. It was drop in retrofit to earlier 1800's and a lot of dealers did them.

Heat management and control of air flow through the engine bay has not been one of Honda's great achievements in the past. So I'm kind of curious to see how the new layered fairings on the new VFR1200 really work.

[Rice]

I've had my 02 through many 100F + days "riding" in a stop-and-stop traffic for extended periods. The temp would creep up to 223, the fan would go on and cool things down to 219 or so every time.

Because of the lack of space and mostly the AMP draw of the two fans running simultaneously, I would suggest taking a look at your coolant and maybe diluting it with more distilled water to get a better heat transfer. More importantly, burp the system to get all the air out of it.

The thinking is that other bikes seem to be cooling fine (for a VFR) and yours doesn't, which means that you may have an issue caused by something other than faulty design.

[ronimalvfr]

I put the Superhawk blade on mine over the winter.Cools off a lot faster when moving now and basically wil hold at about 218 in traffic or stopped.

[Jovinski]

I have to agree with Rice and others. My bike, an '04, has no problem cooling down. The fan kicks on at 220, the temp may get up to about 224 or so before it starts going back down. I have never paid attention to when it turns off, but it's never been a problem. I live in Florida where 99 degrees and 90% humidity is pretty common from late May to late September. Stop and go traffic, mostly stop is also the norm in the afternoon, depending on where you are going. I've never had a problem with my bike overheating. Hell, I don't think I have ever seen a temp above 230.

Also, based on the noticeable draw on the bikes electrical system when the fan kicks in, I don't know that a second fan would do the system any good. That's a lot of amps. Maybe do like Seb said and stagger them turning on, but that's still a lot of power draw to the system.

If you are sitting in traffic and your fan doesn't get the temperature under control, I would think that there is something wrong with your antifreeze ratio or potentially there is something else amiss, like air or a bad radiator cap....

But if you do it, take lots of pictures to show us! :fing02:

[JES_VFR]

I've had my 02 through many 100F + days "riding" in a stop-and-stop traffic for extended periods. The temp would creep up to 223, the fan would go on and cool things down to 219 or so every time.

Because of the lack of space and mostly the AMP draw of the two fans running simultaneously, I would suggest taking a look at your coolant and maybe diluting it with more distilled water to get a better heat transfer. More importantly, burp the system to get all the air out of it.

The thinking is that other bikes seem to be cooling fine (for a VFR) and yours doesn't, which means that you may have an issue caused by something other than faulty design.

Oops, I did something kind of dumb. I automatically discounted that you had already checked your coolant's condition, level and concentration as well as things like your thermostat.

Still, if those things are fine and your bike does try to overheat when not moving, your not alone.

I'd still suggest the VTR fan first and then second ducting before you try third fan.