Need help identifying ways to improve my VFR800's cooling

I came here with this question and not my prefered VFR forum because I like the out of box thinking that goes on here. I also think that you folks are good at sourcing components from sources that others may not think of. Here's what's going on.

On long trips my VFR will reliably not run the fan at the intented turn-on point. The single cooling fan uses a fan switch that screws into the left radiator (as seen from above the bike, the one next to the rider's left knee, etc) that is supposed to provide a ground path to the fan at 220 degrees F. Short trips, like a couple hours or less, and the fan comes on at 221 or 220 per the display very reliably. Long runs, like multi-day trips, the fan has a tendency to come on late, cut out early, and generally act wonky. I've changed the coolant a couple times on this motorcycle using drain & fill techniques and no chemicals or anything harsh. I've seen temps as high as 235. The motorcycle ECU kills the motor at 240 and I don't like seeing the temps that high anyway.

Another issue; Honda, for whatever reason, thought that hanging a puller fan on the inside/back of the left hand rad would be sufficient. Air is blown across the front cylinder head and strikes the backside of the right side rad. Air is felt coming out of the right side radiator when the fan is running. There's some shroud to this single fan but it isn't extensive. The fan is starting to feel a little 'tight', like the bearings are wearing, at 55k miles.

Here's what I'd like to do; get a controller for a pair of fans, have a left side pusher fan come on at some temp closer to 200, and if temps continue to rise, have a second fan on the backside of the right rad push air out that side. This would stagger the turn-on current spike so they don't hit the bike at once and may reduce unneeded cooling power required. Challenges; I don't know what kind of controller would make sense here. I don't know what to do to stop this long-trip bad action with the fan switch. Honda put the ride side of the bike together differently from the left and there's much less space for this new fan. 7 or 8 inches square for a footprint and about an inch of thickness is all I have available. Computer fans would actually work but there's not a ton of air off a computer fan. And they aren't really built for this kind of environment.

The reason I want to change how the fans blow is what happens if the bike is moving forward; ram air flowing through the bodywork effectively stops the airflow in certain conditions. This system works decently when sitting still. It can be overcome over 55 or 60 mph and the bike will slowly cool. 40 mph is a great way to watch the temp hang at 220. There's a fan blade swap from the fan for a Superhawk that turns the stock VFR fan into a pusher and some guys seem to like that solution but it hurts cooling at a stop.

GRM, what have you got for ideas or questions? The bike is down for a bunch of maintenance including replacement of some cooling hoses and this seems like a great time to make some improvements to the cooling system.

What about improving the airflow so that the bike cools more effectively when moving? How many "long trips" have a lot of stop and go, are you usually on the move?

Ducting into and out of the radiators sounds like a simpler solution to me, but I would need to see the area/bodywork in question to better understand what's going on.

EDIT- looking at pictures, are the radiator inlets in a low pressure zone? The whole thing looks backwards to me...

In reply to NONACK:

You're asking me to add an inlet scoop facing forward to the left side of my motorcycle and an outlet scoop facing rearward on the right side of my motorcycle. This also doesn't address the fan cutting in and out only after long trips, which seems like either a connector issue (seems doubtful) or a switch that is wearing out somehow AND doesn't come on at a temp I like.

I'm usually on the move but city traffic can cause issues. The worst I've experienced was stop and go into Milwaukee this past summer where 235 was seen and the bike obviously heat soaked pretty badly per the way it was running.

The temp switch issue is probably the switch itself- can it be changed easily? I was asking for clarification- is it supposed to flow in through the left side and out through the right? It looks like, from an aero standpoint, it should flow in through the front of the bike and out through both sides, in which case giving it a colder air source from the front/inside somewhere seems like the ticket. Like adding NACA ducts elsewhere and running ducting to the inner sides of the radiators.

In reply to NONACK:

Yes, the fan setup is factory; this is how Honda sold these bikes and continues to today. It's not a bad solution if the bike never moved forward and ram air wrecked the situation. Very specific circumstances with forward motion + sidewind has rendered the fan useless with temps hanging above 200 for a long time. If the bike on a roll can drop the temps below 200, the fan will switch off, and the temps then drop a lot faster at that point until it gets close to the thermostat close temp. It's a really dumb solution.

Ducting behind the rads would be hard as there's frame spars in the way on both side. The motor is actually not centered in the frame with a larger gap on the left side for a thick radiator fan. I can take pictures when I get home to better show this setup.

I would do a combination of/or all of:

• Buy a new fan/temp switch if the one you have is wonky
• Clean and lubricate the fan itself
• Backflush the radiator fins to make sure dirt isn't contributing to heat
• Seal any air gaps you can between the fan and the radiator
• Use a bottle of Water Wetter in the cooling system
• Wire a manual over-ride switch to turn on the fan (or off during side-wind issue)
• Use good synthetic oil that won't break down at 240F

Personally, 55k miles is far beyond what I'd expect an oem fan to last. I'd just order an oem replacement and flush the cooling system out with engine ice. The smurfs blood works, I rarely see above 200F with the raptor...and it doesn't have a cooling fan due to the size of the turbo/associated bits.

It looks like some RC51 guys run something like what I was talking about:

The alternative might be to put big nasty scoops on the outside to force air in, helping it go the way the fan intends now. That's pretty much how my 1125CR works, and it cools down FAST once moving. Of course, it also looks like an angry crustacean

Nonack: So that's internal to the bodywork and frame, these scoops? I think it'd be easier to just have two fans pushing air out the bodywork instead of having custom scoops made or put together. And I'd have to if I had these, I think, as the right rad wouldn't get fan air flow with just the stock fan on the left rad installed, as the scoop would block that air movement from across the bike.

GPS: Manual override switch does make some sense and would be easy to add. Probably mount it on the "dash" next to the voltage indicator light. I wish I could get a custom switch that came on around 210 and dropped off at 195 or similar. 220 just seems kind of hot as a starting point to try and cool from when sitting still. But without some add-on controller or different measuring method I don't know how I'd accomplish that.

In reply to pres589:

Yes, and the guys who run those convert to dual pushers to take advantage of that design. Just pushing air out from the inside might not be a good solution without ducting, depends on the ambient temp in there.

Is this what you're looking for controller wise?

Nonack: Oh, snap! That's nice. I wonder what would be a good bolt to use since I wouldn't want something that's in the air stream coming through the bike, so something further back than the front cam cover perhaps.

Finding a thin enough pusher fan for the right side is the next big challenge. Would kind of like to change out the factory fan for a unit that pulls a little less amperage since I'm adding a second fan and it'd be nice to have a null sum change to the charge circuit if possible.

Installing a manual fan switch on my old Honda Magna took care of it's worse heat-up problems.

I'd change out the switch and possibly the fan first.

In reply to BoxheadTim:

Which doesn't really fix issues inherent in the design of this system. I can get by, obviously, if the system is restored to like-new as-new condition. But I figured it would be nice to improve things a little.

Giant Purple Snorklewacker wrote: I would do a combination of/or all of: - Buy a new fan/temp switch if the one you have is wonky - Clean and lubricate the fan itself - Backflush the radiator fins to make sure dirt isn't contributing to heat - Seal any air gaps you can between the fan and the radiator - Use a bottle of Water Wetter in the cooling system - Wire a manual over-ride switch to turn on the fan (or off during side-wind issue) - Use good synthetic oil that won't break down at 240F

This. And if you really wanted to be tricky you could add a little spray nozzle with a water reservoir to spray on the radiator and really maximize cooling! That's all I can think of that doesn't require figuring out new fans and making use of likely very costly ducting.

At 55k I'll bet your rads are a bit clogged. I'd flush those.

I'd use some high quality oils and some water wetter to help once you flush the rads.

Next step would be to replace the fans. I'll bet their bearings are shot or at least less than optimal and that would lower their speed and efficiency.

It isn't uncommon to have some sportbikes that will get hot if ridden at a low speed for extended times.

In reply to clutchsmoke:

Which do you think is harder; figuring out the addition of a fan and mounting a controller, or mounting a water tank + pump + hoses & nozzles. Oh, and keep in mind that any water I spray on the backside of the radiator will probably make it's way out and spit on my legs as I ride. Rider's knees are next to the rads on this thing.

In reply to Xceler8x:

I'm considering fan replacement. Remember that's there's only one fan on this bike. A second fan would be an addition by me.

Not sure on Hondas but many others ducati included use two temperature reading devices on in each head. one tells the ECU the temp the other sends the dash the temp. They often don't read the same. Double check your fan relay socket as well as they tend to act up in higher heat driven under long trips the heat has time to soak the relay and its socket.

pres589 wrote: In reply to BoxheadTim: Which doesn't really fix issues inherent in the design of this system. I can get by, obviously, if the system is restored to like-new as-new condition. But I figured it would be nice to improve things a little.

I understand that part, but personally, I don't like to start out from an unknown baseline. That's why I suggested to bring the cooling system back up to factory spec and then start improving it so you don't end up masking a defect.

44Dwarf: Didn't think about a relay becoming heat soaked. I need to study the wiring diagram and see if one is in the circuit or not. I thought this thing was ground side switched with switched power from the motorcycle going to the fan and the switch in the rad providing a ground path. Hrm.

BoxheadTim: I understand your point. I'm not sure what would be the best path forward, though, and I want to have something in mind before I go replacing anything that actually has cost to it; a new switch is cheap, a new fan isn't.

My Triumph SpeedTriple fan was setup to come on at 218F, so 220 isn't that far off. Does the VFR ecu allow you to modify maps? My Triumph, I'm able to change the temp it come on. I dropped it to 212F.

Do you have room to angle the radiators without cutting the bodywork? Or is there a way to space out your farings and fan on your right side to create more space for a fan?

So many potential options.

Onto the fan, a manual override will allow you to control the fan when you want, but keep the stock setting just in case you forget. I went this route on my old Ninja.

In reply to escort1991:

The fan turn on and off point is set by an old school screw-in switch that goes in the bottom of the left-hand radiator. To change the on and off temps you have to change the switch. Oddly, the fan doesn't quite find a ground through the switch, if this factory wiring schematic is to be believed. It's common with a number of other items. There is no relay for this fan, either, so that theory is out. The ECU has nothing to do with any of this. Really simple system from an electrical standpoint. Manual switch would be a walk through industrial catalogs looking for a two position switch to give me normal operation or a path to ground for the fan separate from the switch. Pretty easy really.

There isn't room behind stock bodywork to kick the radiator on the right side out. If the bike wasn't already apart I'd get a clamp-on ammeter and let the bike get hot and note a few fan on/off cycles to better emulate a real situation. Get some power numbers for normal spin and turn-on then go shopping for a couple pushers that together don't add much more load...

I'm still confused as to why the thing acts up on long trips. The system is so simple that I'm not sure where the problem is. I'm going to assume heat is part of this and maybe an intermittent ground caused by connection issues somewhere.

In reply to pres589:

RE: the long trips... could be heat soak, could be a weak field in the relay or it could be dirty grounds causing a low voltage condition. Maybe a combination of them. Maybe the vreg fluctuating as the alt. gets hot. Check all the base line stuff. Put a voltmeter on it and go for a long ride.

In reply to Giant Purple Snorklewacker:

Let me repeat; no relays in this circuit. There's hardly any relays on the entire bike. And when this has happened the voltage indicating LED I've added showed good voltage conditions. Corrosion or similar issue at a contact or a dying temp switch are about all that makes sense here. The fan itself spins up good and hard when it first comes on.