5th gen fan mod

Discussion in 'Mechanics Garage' started by windunderhawk, Dec 21, 2019.

  1. windunderhawk

    windunderhawk New Member

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    Hi all, Got a 5th gen. Looking to make cooling fan blow out rather than in. Have been informed that a fan blade off a VTR 250 P/N 19009-KM3-003 will work.Any one with experience with this?
     
  2. Norse

    Norse New Member

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    Why?
    Would you rather have hot air from the engine going through the radiator, than cool air from the outside?
     
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  3. windunderhawk

    windunderhawk New Member

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    Last time i checked motorcycles are meant to move. sometimes one cannot be at speed(over 20mph) when moving the VFR uses air flow when moving to push cool air thru radiator and the fan may be running pushing against natural air flow.
     
  4. Norse

    Norse New Member

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    The only "natural airflow" on a motorcycle, is front to back.
    My point is that when little or no air is moving over the radiator, due to low speed, the air under the faring gets really hot. That is why it is set up to draw in fresh, cool air from the outside.

    If what you are worried about is the fan pulling rather than pushing air through the radiator, you will be happy to know that it makes no difference.
    In the custom computer water cooling "community", the push/pull question is a old one. It has been tested to death and every time, it has been shown to make no difference.
    To be clear, a water cooled computer is the perfect analogue for a motorcycle. An enclosed space filled with part the produce a lot of heat, cooled by water circulating through radiators with fans mounted on them.

    If, for whatever reason, you absolutely want more cooling, the way you are going to get it is putting a fan on the right side radiator as well. Or you can fit a manual fan switch. It won't give you more cooling, but it will give you earlier cooling.

    But if you are having cooling issues, you really should find the real problem. The stock system is enough to keep it from overheating.
    Even in very warm weather this summer, mine could be sitting in stopped city traffic with zero problems. The temperature would climb until the fan kicked in and hen start to quickly drop back down. It never goes higher than it should and the fan can actually make the temperature drop rather than just keep it from getting higher.

    If yours can't do that, there is something wrong. Could be a faulty thermostat, bad plumbing or any number of other things. Figure that part out first. Unless you are starting with something in perfect order, an "upgrade" is just a patch.
     
  5. windunderhawk

    windunderhawk New Member

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    Ok I understand. I would think where you tend to ride is a lot cooler and wetter. I usually ride in the pacific northwest and in the summer it can get in the 90s with low humidity. My concern is when moving at 30 to 40 mph my 98 with 26000 miles and a manual fan switch can get 220F and not cool back down until 50 mph with 90F thermostat replaced. Thanks for the input ill check other possible issues first. Do you know what temperature the stock thermostat opens.
     
    Last edited: Dec 22, 2019
  6. windunderhawk

    windunderhawk New Member

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  7. RllwJoe

    RllwJoe Member

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    My '98, as best as I can determine, will reach 170*F when the themostat will begin to open.

    If the ambent temp is less than 75*, and my ground speed is above 40MPH, the coolant temp indicated on the dash will bounce between 168* and 174*. That being said, if I'm at a full stop long enough the temp will rise to 220* when the fan kicks in and will lower the temp quickly to around 185* where it kicks off.

    In 90*F weather, other conditions being the same, while moving the coolant temp will bounce around 180* +/-.

    When was the last time the cooling system was flushed? Has the themostat been replaced? It may not be opening all the way when it needs to.
     
  8. windunderhawk

    windunderhawk New Member

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    Thanks for the input.gives me a basis of what to determine comparing my 98 to yours.mine has 26000 and the thermostat was changed at 12000 by the previous owner.Now thinking did they bleed the air out easy fix? is the thermostat sticking not so easy? most wouldn't worry but im one of those that know too much heat is not good.gonna replace thermostat flush coolant and air bleed.
     
  9. Norse

    Norse New Member

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    About the same for my 2000. In hot weather and slow/stopped traffic, it will get to 103C, the fan will start and the temperature will drop back down. The highest temperature I have ever seen was 104C and that was during a heatwave and while stuck in traffic.
    That is pretty much the temperatures you are seeing and that is completely normal and within spec.

    The but the fan should be able to make the temperature drop. If you are in a REALLY hot climate, I would not be surprised if the fan is only enough to keep it from going higher than that. But those temperatures are still within normal and safe operating spec and reversing the direction of the fan will do absolutely nothing.

    The only thing you can really do to get better cooling, is adding a second fan on the right side radiator. Or installing a manual fan switch to turn the fan on earlier.

    But it still makes sense to check the cooling system. Figuring out IF there is a problem is always the first step.
    Air in the system can cause problems, but even if the previous owner didn't bleed the system properly, any little air bubbles generally will work themselves out relatively quickly. If not, bleeding the system is easy and since changing the coolant and flushing the system is a good idea no matter what, You will be doing that anyway.

    Checking the thermostat can be easy. If it doesn't close, the radiators will heat up before the engine reaches operating temperature. If it doesn't open, the radiators won't heat up after the engine reaches temperature.
    But in your case it doesn't seem to be stuck full open or closed. If for example it "works" but won't open all the way, it could be very hard to check without taking it out. If that is the case, you won't be happy. Getting that little bastard out is not a simple 5 minute job.
     
  10. windunderhawk

    windunderhawk New Member

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    Ill just flush and bleed and call it good, Thanks for the information.
     
  11. RllwJoe

    RllwJoe Member

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    The thermostat is hard to get to. But not impossible.
    You're welcome. When I flushed mine I had a lot of sediment that came out so I flushed it two more times and had less each time. I used a 50/50 mix of water and vinegar. It seemed to work very well. I also swapped out the themostat because it was stuck open and would not get up to operating temp in cooler weather.
     
    Last edited: Jan 20, 2020
  12. windunderhawk

    windunderhawk New Member

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    Cool, gonna do a flush and use Engine Ice.
     
  13. Sirdoh

    Sirdoh New Member

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    I just flushed changed the coolant in my new to me 2011. No improvement in low speed cooling. I was studying it on my way home tonight. At 20mph just not enough air going into the front so at 97°C (206°F) the temperature keeps rising. If the fan comes on it just won't cool down until I either stop completely or drive above 28mph. I don't spend much time stationary except at the lights. The VTR blades mod is starting to look sweet. I'm searching for pictures.

    What happens to engine oil at these temperatures? No one ever mentions the oil cooler. I wonder if that could use some help.
     
  14. windunderhawk

    windunderhawk New Member

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    Greetings from across the pond, There is another forum called VFRDiscussion.com there are posts on there with good information and photos. I did a coolant flush and used Engine Ice, its spendy but works,with my 98 seems to solve problem.I also did the VTR fan just cause it makes sense. I do not believe oil cooler mods will make a difference. Most important to make sure thermostat is functioning properly. Good Luck.
     
  15. Sirdoh

    Sirdoh New Member

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    I can't get registered. First time It didn't like my user name and the second time it didn't send me a confirmation link. They won't reply to my messages.
     
  16. Sirdoh

    Sirdoh New Member

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    I wanted to perform this mod myself and test it in traffic before I responded. Its important to understand that BOTH radiators and the engine are part of a system. If you are pushing hot air through the radiator you must have pulled that heat from the engine, so that is still a win. Secondly, emptying the hot air from that area means that the other area has cool air to work with.
    Well, I did it and it works. Stationary seems to be about the same but when moving at 10 - 25 MPH I could watch the temperature ticking down. Earlier this week I had been riding at 28 and seeing no change. As you take heat out of the system you reduce the average temperature of the engine block and the number of fan activations.
    You need to drain the coolant and disconnect the bottom hose, so that's an excuse to change the coolant anyway. For me it was a bonus because the bottom of the radiator had some plastic film in it. perhaps the inner coating. Anyway you really don't want that breaking up and clogging up the small pipes.
    I also did the PAIR mod, flapper and snorkel. This bike is as well behaved as my old CBR500R now.
     
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