5th Gen - Overheating, Thermoswitch Replacement?

Discussion in 'Mechanics Garage' started by duder, Sep 22, 2009.

  1. duder

    duder New Member

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    I have a 98 VFR, 21K miles. I've owned the bike for almost 2 years and absolutely love this "1998 bike of the year."

    I'm turning to the gurus of all that is 2 wheeled for some help...

    During the last few months, I've been chipping away getting the standard work on the bike done that almost any vehicle should have performed. Meaning I have done the oil every 3K mi or so, changed the spark plugs, air cleaner (had a mouse nest in it. nice. thanks for taking care of it previous owner!), a valve adjustment needing 2 shims, clutch/brake fluid, chain and sprockets, brake pads, tires, and coolant.

    The coolant is a more recent check, I had a bike repair guy do it a couple months ago along with the valve inspection. After the coolant was changed, I noticed that the new green stuff he put in made the bike seem to run a bit hotter. I've never gotten the overheat warning, but I've gotten as high as 240 F while sitting in city traffic. Usually when I'm moving in the city for extended time period, my temp will still sit around 200 - 220F range on a 90 degree day. On the highway on a hot day for an extended time, I'll be running around 190 - 200 F. I've had it boil over a couple of times after shutting the bike off.

    Well, the high temperatures did not sit well with me, so I read the write ups on here and switched to engine ice (after flushing twice with distilled, of course). The engine is still getting hot enough in the city that I hear the coolant boiling after I shut the bike off. Not good. Again, never topped 240 F, but still concerning. I read up on the forums here for overheating problems. Could be the thermostat, air in the system, the thermoswitch, radiator cap, an obstruction in the lines, among other causes. Oh yeah. Forgot to mention. The radiator fan never kicks on! In fact, I don't think I've ever heard the fan kick on before... sounds like the thermoswitch or the fan to me.

    I don't have much in the way of testing tools for why the radiator fan doesn't come on, so I bit the bullet and took the bike to the dealer. Dealer looks over it, says its the thermoswitch and the radiator cap that need replaced. $250 parts and labor. Sounds about right. The dealer usually does pretty good by me... But in the attempt to save some $, does anyone know how to replace the thermoswitch ($50 part on bike bandit) or where I could find a write up? I like pictures. How difficult would it be? Haha... I think I can handle the radiator cap...

    Any advice given is appreciated, thank you!
     
  2. Joey_Dude

    Joey_Dude Member

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  3. Pliskin

    Pliskin New Member

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    I'm not mechanically inclined enough to help you out, but I did have a problem with the fan on my 5th Gen as well. As it turns out, the fan had gotten "stuck" for whatever reason (debris, etc.). Since it wouldn't turn, it blew the fuse. Stuck my hand down there one day (bike off) and was trying to spin the fan, which it eventually broke loose. Now spins smooth as can be. Obviously had to change the fuse.
     
  4. Meatloaf

    Meatloaf New Member

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    It sounds like more than anything you could use the service manual so that you know what you are looking at and where to find things. Seems like you are mechanically inclined enough to handle just about anything that needs to be done as well.

    Check out this thread: http://vfrworld.com/forums/parts-se...nloadable-parts-catalogs-service-manuals.html

    Download the 1998-2001 Service Manual and it should provide you with all the details that you need to do this and more. Be warned that it is a large file... about 180MB.

    I can't speak for how difficult it is but I doubt it can be too bad. Especially if you take your time and read the manual, it will probably be a piece of cake and the most specialized tool you will probably need is a six pack for completion of the replacement.
     
  5. dino71

    dino71 New Member

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    A few things I did to lower operating temps was to remove the pair valve system, there might be a how-to on this board on how to do this and your bike will loose about 5 pounds in the process, it takes about 1.5 hours to do and you only need to buy minimal parts, all of which I got at a local Napa. Second it to replace the thermostat, if its stuck then you are screwed and its a pain in the ass to change, make sure you own a long phillips #2 screw driver to loosen then throttle body boots because you guessed it the theromostat in under it . Another thing I did was add 12oz of Red Line water wetter to my antifreeze, you can get this from any autozone or any good auto parts store. All this has made significant improvements to keeping my water temp down. What happened now it that it takes a little longer to warm up to 95 deg.
     
  6. duder

    duder New Member

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    service manual download link, thanks very much! I'll just have the dealer get it done for now... I've got some weekend riding coming up and I don't want to screw around with it. appreciate all the responses!
     
  7. mello dude

    mello dude Member

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    If you can change a sparkplug, you can change the fan switch...
    Also, you might want to "burp" the hoses and add antifreeze. Its best done while the bike is on the side stand.


    Good luck,
    MD
     
  8. CandyRedRC46

    CandyRedRC46 Member

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    +1 i think ive changed the switch about 5 times, playing around with different temp settings. it really isnt that hard...
    also with your coolant boiling over a few times you could have air in your lines.
    if you wanted to concur this i would say:
    1st check the fan blade and make sure it can freely spin, no interference with fairings, radiator or engine block.
    2nd check the fuses
    3rd knock that switch out, if the first two steps are fine.
    4th if your still having problems, burp it, which you would need to do after pulling the switch anyways...
     
  9. duder

    duder New Member

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    thanks for the good advice. I'll read up on how to change the switch. the spark plugs weren't bad so that gives me some confidence.

    I have to admit, I've seen the term "burp it" in other threads, but not sure entirely what that entails. I mean, I'm a strong guy, but I don't think I can pick up the bike like a baby, throw it on my shoulder, and then repeatedly smack the heck out of its back! *buuurp*
     
  10. CandyRedRC46

    CandyRedRC46 Member

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    lol too funny bro! :pound:
     
  11. mello dude

    mello dude Member

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    Burping is a goofy term thats come up -- how to? Run bike and warm it up - 180 - 190 is good. Shut down, wait and cool down. Set bike on side stand and crack open the radiator cap. See fluid? Grab and squeze hoses, cross hose in the front and water pump hose on the side. It should force any air bubbles out to the filler opening. Then top off the fluid. -- 2 or 3 times is a good idea. That's what it took on mine when I changed the fluid to get all the air out of the system.

    The fan switch is on the left radiator. It sticks out like a sore thumb on the front edge of the radiator, you cant miss it. Its ez - just pull the connector wire off, unbolt old, bolt in new, stick the connector wire back on. Then fill up the radiator fluid and do the burp routine. As candyred said - reach behind the left radiator and see if you can spin the fan blade by hand. If not you got other sticky wickets to screw with.

    Good luck,
    MD
     
  12. pyrofitr1368

    pyrofitr1368 New Member

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    I went to Fire Blade .org this morning for the same concern.One of the members there found a fan switch with the same thread and depth.It turns out our fan switch is used widely in Honda bikes,his being an '01 RC51. I went to Advanced Auto and ordered the new switch. If anyone is interested, I'll post my results.Remember I am using the idea from a thread on Fire Blade ( I don't take credit for other people's work).
     
  13. CandyRedRC46

    CandyRedRC46 Member

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    bro why are you trying to take credit for other people's work!
    j/k lol :tongue:
     
  14. pyrofitr1368

    pyrofitr1368 New Member

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    I noticed you have the pc usb3 but why do we need to get rid of the o2 sensors?What are the benefits? I am new(two weeks ) to the VFR.
     
  15. CandyRedRC46

    CandyRedRC46 Member

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    they are not true o2 sensors (wide band o2 sensors) like the ones used in an automobile and some motorcycles... they are narrow band o2 sensors, which are only used during light, steady throttle (like idling and cruising). the bike's ecu takes in the data gathered by o2 sensors and compares it to the air/fuel map, then determines how much further it can safely lean out the air/fuel ratio to lessen exhaust emissions and promote higher fuel millage.
    this causes a lot of surging and lurching etc.
    o2 eliminators alone will make the bike perform much better.
    adding a properly tuned power commander to the o2 eliminators makes it perform almost flawlessly.
    i have heard that the bike can not be tuned correctly with out o2 eliminators and the power commander and ecu will not get along with out the o2 eliminators either.
     
  16. pyrofitr1368

    pyrofitr1368 New Member

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    Is this for all vfrs?I have a fifth gen w/ pc2 and Micron can...
     
  17. CandyRedRC46

    CandyRedRC46 Member

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    yup from 2000 and up they were equipped with o2 sensors.
    hopefully who ever put the pc2 on yours was kind enough to do the eliminators too. if not you can always get the 99 cent 330 ohm resistors from radio shack, if you don't feel like paying 30 bucks...
     
  18. duder

    duder New Member

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    ahh sweet sweet thermoswitch replacement, the fan now kicks on at 215 deg F.

    now the dealer is saying I have a sticky/worn stearing bearing in my triple tree or something like that? sounds suspicious. sucker steers and stops like a champ.
     
  19. CandyRedRC46

    CandyRedRC46 Member

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    whats it like with the bike on the center stand?
    front tire in the air, how does it steer? freely?
     
  20. duder

    duder New Member

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    yeah, i have no issues with how it steers. the front tire turns freely from side to side, don't feel any odd resistance or difficulty in turning.

    sounds like they want my $$$
     
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