Cooling fan-push or pull?

Hello fellow VFR’s

I recently replaced the plastics on my 99when I was hit and sent sliding while lane splitting ourt here in NorCal. But since she’s been put back together I noticed she fern warm (190-200)when in stop and go traffic on rm days. So, I checked the fan and she blows air very well. But oddly (at least to me) the air is drawn in from the outside and pulled through the radiator towards the engine. While yes. This men’s cooler outside air is dram inset of hot exhaust engine ir. Would this fan be fighting the natural wind flow cooling that the bike inherinegtly has. ? So the questions is are these fans suppose to push air or pull air??

Thank you,
You guys are always a great help.

Jim D

 

190-200 in traffic is much cooler than my 98 and 00 run.

 

I believe I read elsewhere that Honda is okay with up to 240F before one needs to be concerned with cooling system.
Ambient heat, slow moving and the like have pushed mine to the 220’s on occasion.
Apparently that’s within the normal range.

 

The stock VFR fan pulls air in from the outside.

If you read the owners manual it states that if the temp reaches 122C, its time to switch off and let the poor thing cool off. That is 252F.

The basic values for a VFR are;
1. Thermostat open (i.e. the minimm running temperature) 78C or 173F
2. Fan on 102C / off 98C 216F/208F
3. Red zone 122C / 252F

My opinion is that the digital gauge and the numbers cause unecessary anxiety; back in the day of a needle gauge, if you hit the red zone you knew there was trouble, but everywhere else was OK. The values above would correspond to roughly 1/4, 1/2 and 3/4 on a gauge.

Interesting that more recent bikes (my VFR1200 for example) use a digital bar gauge with no numbers displayed.

 

Ok, so I wont panic bout the temp being around 200. But I still find it odd how the fan is pulling air in while the natural air flow is trying to push it out. They’re fighting each other.
Thx for your input guys.

Jim D


Sent from my iPad using Tapatalk

 

I think you are right to a point but there is probably method to Honda's madness.

At a complete standstill, the air on the inside of the radiator will be gathering heat radiated off the header pipes, so that air is likely to be much hotter than the air around the outside of the fairing. From a cooling standpoint, pulling air in from outside is logical, and the same happens with a regular forward facing radiator.

When you are moving you are correct that the air pressure on the inside of the radiator will be higher than outside and will oppose the fan, but there is the right radiator participating in cooling then, and the single cooling fan is probably only affecting 50% of the left radiator in any case.

 

There is a reason why you don't see this radiator location anymore.

 

It's in Honda's DNA! Don't fight it!

 

I'm pretty sure neither one of those vehicles was ever in stop and go traffic or seen sitting at a traffic control light, and yes, I've seen it too ;-)



But they did quickly learn and correct the errors of their earlier mistakes





Only to bring back the abortion and foist it onto an unsuspecting public.

 

Well I think the NR500 was in stop and go traffic (as in it stopped, and then wouldn't go).

I believe what we are observing is called "marketing". When Bold New Graphics aren't enough, INNOVATE! Add those side-mounted radiators! Make a really complicated brake system! VTEC Yo!

Other manufacturers are not immune to this, remember the rotary damper on the TL1000S?

 

I actually have a framed photo of the only time Suzuki took a factory TL to Laguna for WSBK. It was ridden by Steve Crevier. I had the photo blown up and Steve signed it for me at a later race. It is tucked away in storage now.

 

Do you have any idea how many modern engines employ VVT? My 2006 Tacoma 4x4 has VVT actually. I happen to have built a 6g engine (top end only) with an engine builder friend of mine and I can tell you this, that thing would stomp the shit out of any 5g and it was smooth as silk.

 

Yes I'm well aware of VVT engines but the key there is in the first V i.e. variable. Even my daughter's sh1tbox 2000 1300cc Toyota Duet had an intake cam phaser! And I believe the VTEC cars use something more akin to the Shiftcam system that moves valves to a saucier cam as the revs rise.

AFAIK Honda VTEC is unique in the 2V / 4V operation. As a current owner of both a 5th gen and a 6th gen you can't persuade me that VTEC is a game changer for power in stock form. About all it adds is some "character" (it's a feature, not a bug!) at the cost of some horrific maintenance costs when it is time for valve clearance checks (unless you DIY). My 09 runs really sweetly without a horrid step, but the power is not linear like my 99.

But you have me interested in the built 6th gen. What was done to it, and what was the result?

 

Hahahaha, you weren't here in the mid aughts, I don't believe. This place was dominated by 5g riders going on about VTEC sucks, VTEC is slow, VTEC does not make sounds like a small block 350 with a gear drive, there was no end to the craziness. So, I had just bought a 6g and went about turning it into something that would chew up 5g's and spit out the gear driven cams. I thought it sounded even better than gear driven cams when it spooled up. It eventually turned into a friendly rivalry between the 5g and 6g guys. Us 6g guys got together and we formed the 6g Milita, Randy even had patches made, there were quite a few 6g guys that joined the ranks. Over a couple hundred, if I remember right. The best part was when I would let 5g guys take a little spin on my 6g.....the attitude change was hilarious. Good times, but we were always VFR brothers, no matter what.

 

Nope I missed all that. I was out of the VFR loop for a few years until a bought my 99 in 2014.

Are you saying the VTEC is better than a 5th gen as long as you rebuild the motor with hot-up parts?

I do like my 6th gen a lot BTW. I just don't subscribe to the VTEC Kool-Aid.

 

I actually felt the overall chassis was more refined and I liked VTEC. Reminded me a little of my 2 stroke days growing up. I always laughed when people were scared of the VTEC, it was fairly obvious they didn't grow up riding 70's RD's and 70's and 80's 2 stroke mx machines. All the 5g's I rode seemed clunky and outdated compared to the 6g. But that's just me and I really don't want to start this whole stupid argument again. If you like 5g, so be it. I'm not going to shit on your personal choice.

 

Actually I agree with your assessment, the chassis is better/steadier on the 6G (probably due to the 43mm forks and longer swing-arm) and the VTEC step does give it character; I also started in the early 80s and remember riding RD350LCs occasionally. I also find the engine to be smoother and (keep this quiet) free of the occasionally annoying gear whine. And the styling is one of Honda's best eforts, especially the back end.

But...couldn't we have had the same result but without VTEC, just through improvements to cylinder head design and injection?