another 'am i running too hot' thread?

Honda coolant is pre-mixed 50/50 already, or so the bottle lead me to believe.

i only fill with premium, which in NC is 93 octane. i try to fill at the 'better' stations when i can, but when you get on some of these rides in BFE.......

as far as what i consider normal...... i dunno. i don't have a TON of experience with this bike yet, and i don't have a lot of experience with bikes in general. BUT, my previous bike was a SV650 that NEVER got this hot. i ride with a bunch of CBR and Gixxer riders whose eyes go WIDE when i tell them what temp i'm running at, especially when compared to what their bike is running at.

so, i ride on, i guess. i mean, FWIW, the bike runs just fine. power's good, no stumbling, nothing. it heats up the boys a little when those fans start kicking the air around, but other than that i'm good.

why did Honda have to give me that damn gage anyway? i'd be blissfully ignorant right now if i just had a craptastic needle gage or nothing at all like some other bikes. maybe my 'solution' should be a piece of electrical tape over the gage, lol.

Mike

 

Yeah Honda is premixed 50/50 but if you have had an evaporation of the water in your tank and you add more premix you will be increasing antifreeze to water ratio.
Also running premium 93 is not required in these bikes. They are tuned to run on 87. Your bike will compinsate for the increase in octane. I have found that running 93 will raise my engine temp. Also the addition of ethenaol makes the bike run lean raising engine temps. Granted only a couple degrees. But these bike do run hot. They run hotter in slow stop and go than just sitting still. also one they get up there nad the outside air temp is hot say up in the 90's then they do not cool off very quickly.

 

Your temps are very similar to my '02 VFR. It ran hot - especially on warmer days and in slow traffic. One day I was going over the Cuesta Grade (near SLO, CA) and due to a traffic accident we were crawling along. My temp hit 138 deg right as I crested the grade. I was pretty paranoid and coasted (with engine off) for a few miles to cool it down. I wish Honda would have set the fan to kick on at 200 or even 205 degrees....wouldn't get so hot then. I'd like to find a cooler sending unit (for my 2007 VFR) to accomplish this. Anyone know of Honda offers a cooler sending unit? Years ago at the bike races in Laguna Seca, someone told me he had used the sending unit from a SuperHawk as it kicked on the fan at a lower temp...never was able to find out if this was accurate or not.

 

definitely know the area. i'm Cal Poly alumni

Mike

 

OK, newb question time.
My 2000 boiled over the other day after hitting 252. So...I flushed the whole system checked hoses and cap, put in 50/50, then ran her up.
She rolled right past 220 with no fan. Shut her off and checked the fuse and connections-all good.
Is there something simple to check next before I buy a new fan?

 

In your checking of connections, did you test power to the fan itself? If you have power going through, I'd suspect a bad fan unit then.

 

Thermostat... in the service manual it shows you how to test it. IMO I would recommend just buying a whole new thermostat since they're not that expensive and they need to be replaced every 2-3 years anyway.

 

I have to say I'm skeptical on the superhawk fan mod for a 5th gen bike. The fan is a DC motor, so reversing direction is as simple as reversing the leads. No fan motor swap necessary. I tried it with poor results.

The change did require cutting some wires as there is no simple plug to reverse. Once done I found pretty much what you would expect. I trolled around in stop and go mode for a while and allowed the bike to get hot and the fan to kick on. Once the fan was running I kept going at stop and go type speeds. Instead of cooling down or stabilizing in the typical 217-235 range, it shot up and overheated. I pulled over, shut it down, and let it cool off. I then repeated the experiment but when the fan kicked on I jumped onto the nearest freeway (I did all of this in the middle of the night so traffic wouldn't interfere with my test speeds). At speeds over 60 or so the bike did cool down and the fan kicked off, seemingly faster than it normally would under the same conditions.

Here is what I deduced happened. At stop and go speeds with the fan on, the bike was blowing air that had already passed slowly over the pipes and engine, and hence heated, across the left radiator. So instead of drawing cool air from outside the bodywork across the radiator, I was instead blowing heated air across the radiator, heating the coolant up further or at best breaking even on heat transfer. At freeway+ speeds the bike is drawing in air fast enough that there is not significant heat transfer from the pipes and engine to the air that subsequently flows over the radiator, and you get enhanced cooling because the fan is blowing the same direction as the vehicle speed induced air flow.

This makes sense if you consider what honda did with the 6th generation fans, that is they added a reversing relay to the fan. At low speeds where induced airflow is slow the fan blows from the outside in, at some speed the fan relay reverses and the fan blows from the inside out, the same direction as the induced airflow. Honda also did this with the goldwings.

I put the fan direction back to the original. For my next project I am adding a switch to force on/off the fan. I plan on doing it with a relay and a holding circuit. That way I won't be able to accidentally leave the fan off after stopping and restarting the bike. Since my biggest peave is getting the fan stuck on, say 45-65 mph, the fan kicks on but never off, I would like to be able to temporarily turn the fan of. If I can find a timing relay small enough I would like to set it up such that I hit a button and the fan stops for a programmed time, say 2 minutes. That is long enough to allow speed forced airflow at 60+ mph to cool the bike.

 

OK, so it's not the fan or the switch causing my particular issue.
I cracked open the fan switch and bled some air out of it.
Started her up and ran her to 220--fan turned on and cooled her down to 207-just like it should. So next step is road test her to see how she does on the asphalt.
The coolant I drained out was nasty/milky green. I have replaced it with 50/50.

 

Road Test Results:
40 minutes
about 15 miles
100 degrees outside
various speeds
in and out of traffic
max temp=238 for the last 5-10 minutes
fan-on at 220

well, what do you all think?

 

I might have everyone beat. Once again the expressway turns into a parking lot here in Atlanta the other day. Barely moving at all. 95 degress out side. I hit 249. I was like "holy crap" and turned it off for a second; the bike only got hotter. I cranked it back up and it starting cooling off a little. Guess cause it's water cooled. Came real close to lane splitting to get out of traffic. But didn't. Hung in there and sweated it out. Once I got going It ran about 233-237.

 

252 is when it boils over

from experience

 

Yeah see I don't know about the 5th gen, but on the 6th gen I have an indicator light. It should flash when the bike is running too hot and I need to shut off the engine then. I had my eye on it yesterday.

 

Muzzy makes a replacement fan for the 90-97 VFR's that supossedly cool the bikes faster.

I saw them advertized in dennis-kirk catalouge.

I have no idea if they will fit newer model VFR's, but just a thought.

BZ

 

The temp guage on the 2000 blinks above 250
Not much you can do in construstion traffic for over 10 miles at 5mph.
No where to stop, can't slow down, can't speed up...

 

Personally, if the fan is coming on when it should, the coolant is not boiling over, and the warning light is not coming on, I don't worry about it. Although 235 sounds like it is too hot, it is probably because of what we are used to historically.

For comparison, the old "F" series air cooled Hondas (CB750F, 900, 1100) were known to cook non-synthetic oil on moderately hot days while cruising down the highway at 65MPH, which meant that the oil was reaching at least 265 F (I think 265 was/is the oil breakdown number). My point is that although 235 sounds hot, it is within the expected operating range, and the only time that the warning light will come on is when it is outside of the safe operating range.

I live at the end of a hilly road with a 15MPH speed limit. It's a little less than a mile in length, and even when it is 35F outside, the VFR and the SV have their cooling fans running by the time I get home. It used to bother me, but I just got over it.

Now I let other things bother me instead. :smile: :smile: :vader:

 

While I do understand where you are coming from...I still would like to find a way for it to run cooler. As when it's 220+ degrees, the engine is hot and you can feel the heat on your legs...not to mention that running that hot can't be good for the engines longevity. I really think Honda sets that fan switch so high due to emissions - hotter engine/catalytic converter = less emissions, but we suffer with engines that don't need to be running so hot all the time. Add to that the fact that side mounted radiators are some of the worst for cooling and you have a hot running bike that gets hot too quickly...I wonder if we could mount a second fan on the other radiator:unsure: I still say the best way would be to install a replacement temp sensor switch that would kick the fan on at 190 or 195 deg.