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Help FZR250 2KR Water pump replacement + Clutch replacement

Discussion in 'Yamaha 250cc In-Line 4's' started by Brandon Otte, Apr 2, 2020.

  1. Brandon Otte

    Brandon Otte Active Member

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    Hello again,

    So this time round I'd like to know if anyone has a guide or photos or any information at all regarding replacing a FZR250 water pump and the same thing for replacing my clutch.

    The water pump is only a maybe after I've solved the temp gauge issue rising when headlights are on.

    The clutch will be after that too, but, I'm certain it's due for replacement - I have read some engine oils will prolong it's life, which is why I'm posting this for all the help I can get.

    Thanks in advance!!!
     
  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Is it running hot verging on overheating, or is it just the temperature gauge rising when the lights are turned on that has you worried?

    Only reason I ask is perhaps the thermostat is on the way out but hasn't yet failed - IIRC there's a thermostat out of something hyundai or Isuzu which fits and should be easily to find - I'll search my notes later

    As far as oil, you want an oil without friction modifiers as they can make motorcycle wet clutches slip
    Now with that said you can now use API SN oils in a motorcycle as the friction modifiers which could potentially lead to clutch slip were in API's SJ-SM

    https://totachi.com/news/api-rating-system-for-motorcycle-oils/

    Each new API specification is for the latest specifications as well as encompassing the prior specifications

    Many here are using Delo 400 Diesel oil with great results - it's mixed fleet, excellent base stock, no friction modifiers, good with transmissions and obviously good with the duty requirements of diesel, which is a harsher environment that a motorcycle. It's price is a reflection of the quantity produced, not low quality - change it regularly and be happy.

    Replacing clutch plates itself is a quick and easy job, good possibility that the gasket will tear when you remove the cover so have some gasket paper to hand to make another one.

    The trick with clutch plate replacement is remember the order of plates and the spring in amongst them and I believe it's recommended to soak the new friction plates overnight in oil. Metal plates are subject to measurement for warpage, thickness and any signs of burning, subject to less wear than the fibre plates

    You can use an ink pad to wet the entire gasket surface on the cover then make a stamp and cut the lines - a hole punch will assist enormously with the bolt holes

    Hope this helps
     
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  3. Brandon Otte

    Brandon Otte Active Member

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    So it's running hot verging on overheating with the lights on, with the lights off it will get to a max of around 2/3s to 3/4s. The lights on makes the gauge jump up considerably to the point it's just under the 'danger zone' (red zone). So this is after I've been running bike for 10-15 minutes, gradually gets up there - I have also noticed the gauge will rise suddenly with high rpm's and drop as rpm drops, not sure if this is anything worth noting.
    Also another member recommended the Nulon premix long life red coolant, I've heard only good things about it? Is that worth a go too? I'm running green stuff atm.

    Here's a video if you watch the gauge.

    (yes there's another video with out the muffler :))

    So that's with the lights off after a short ride and idling for 5-10 minutes you can see the gauge is higher than I would imagine it should be, if I flicked the lights on it'll get right up there.
    There's also a red button under the gauge which a previous owner installed to manually run the radiator fan.

    I replaced the thermostat housing a few weeks ago with a straight replacement one which is complete with sensors and thermostat to see if that would help, I didn't want to open the original up without knowing what thermostat and temp switch etc so got a spare for $20.

    Yup thanks alot for all your help it's super helpful! I'll be searching for some Delo 400 oil, just make sure I get the correct one.
     
    Last edited: Apr 3, 2020
  4. Linkin

    Linkin The Apprentice Premium Member Dirty Wheel Club Contributing Member

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    That red coolant is not meant for alloy engines. The FZR runs cast iron cylinder liners too, so you have dissimilar metals. Flush it with water and fill it with green stuff.
     
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  5. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK I can see what you mean about the needle deflecting when you rev the engine and it does look to be abnormally high after that amount of time running.

    So when you replaced the thermostat housing, thermostat and sensor, the coolant was drained, at least partially.
    What was the condition of the coolant like?

    I think it's sensible to check the water pump at any rate.

    Here's my theory:
    There could be two gremlins, just putting it out there - wondering if the regulator rectifier is on the way out and the voltage is rising excessively when you rev AND there's potentially a problem with the water pump as you suspect.

    OK, I just did some revision reading as I recall getting this backwards many years ago - the temperature sensor resistance reduces as as the temperature rises - called negative temperature co-efficient NTC, which means that the voltage/current to the gauge increases with an increase in temperature - that make sense.

    If the Regulator/rectifier is on the way out it will likely be beginning to overcharge the battery - two reasons to suspect this - the temp gauge fluctuates with engine revs AND it the temperature gauge reading high.

    Do you have a multimeter that can just read DC volts to check how high the charge voltage goes when you rev the engine?

    Keep in mind that this doesn't make complete sense as when you switch the lights on the temp gauge rises, unless they are drawing enough current to take the top off excessive AC coming through the failing regulator/rectifier - that part I can't quite reconcile, unless having the lights on somehow give a better earth for one which isn't great otherwise and allows better conductivity for the gauge as a result.

    @GreyImport I think was the first member to recommend the red coolant because it's long life, designed for alloy engines and as a result doesn't become corrosive as it degrades over time.

    You can make a coolant flush out of distilled or demineralised water and cleaning vinegar 50/50 or lower, it will over time remove any scale which may have built up.

    I was doing this on my Subaru and it works a treat, actually left it in for over 1000kms - the car is dead, but not from that.

    OH and Delo 400 is Caltex, it isn't sold everywhere, but should be available at some service stations if you cannot find any other sources.
     
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  6. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    OK, this is interesting, I thought it was meant for alloy engines - my bad, I haven't personally used it which is why I tagged @GreyImport for comment
     
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  7. Andych

    Andych Senior Member Premium Member

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  8. Brandon Otte

    Brandon Otte Active Member

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    Yeah so the coolant was mint, looked like new. I completely drained the system before changing the thermostat housing so to save all the coolant.

    That's very interesting about the regulator/rectifier, I'll have to find where it is and test it?
    Yup I have a DC multi-meter, what voltage at the battery should I be expecting while revving it? 14 - 15 volts maybe?
    What would be a definite number that indicates a failing regulator/rectifier.
    Just a note I've never had any hard starting or slow cranking - from what I've read they either fail causing high charge or low charge.

    Yup temp sensor makes good sense.

    So with regard to the water pump does anyone have a photo of one open and where would I find a replacement?
    I originally suspected a bad earth near the temp gauge which could explain why it rose when the lights are flicked on, following that another member pointed out there should be an earthing wire from the thermostat housing to the loom which I don't have on mine. May be because it's a 2KR model but still worth an investigation, would explain alot.

    What I'm thinking is I'll start with searching for an earth wire on the thermostat housing - I did replace the housing not long ago so I'll also check the original thermostat for correct operation.

    I'll check the charge at the battery using DC only - if that checks out okay I'll then go onto opening the water pump.

    The oil I'll do after I've resolved the current issues.

    Thanks again for all your help it's really great so many people on here are so willing to take some time to share their experiences and knowledge! :)
     
  9. Brandon Otte

    Brandon Otte Active Member

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    Here's the image from another member showing the earthing wires:
    thermos3ln.jpeg
     
  10. Brandon Otte

    Brandon Otte Active Member

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    And here's my 2KR housings:
    IMG_3545.JPG
     
  11. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    I'd make an earth wire first thing because looking at it there may have been one originally - difficult to know for sure and given that the thermostat housing is insulated from everything else by rubber hoses it may account for something.

    You could take it from the housing and go straight to the main earth on the frame, tie it in with the loom.

    It doesn't make a while lot of sense without knowing which way the current runs, but it's simple to do and worth a shot.

    To test the regulator/rectifier just check the voltage at the battery, it should be mid to low 14 volts from memory - the actual spec is 14v @ 5000RPM - the reg/rectifier's no load voltage, i.e. when it's disconnected from the battery is 14.3v - 15.3v, BUT I wouldn't test that as the charging system doesn't like not having components connected - not sure where I remember that from, and I could be wrong, but just in case.

    So over 15.3 volts @ 5000 RPM, checked at the battery terminals, I think is suspicious - the usual gotcha for a failed reg/rectifier is a boiled battery from being overcharged and by that time it's too late, it's either that or a completely flat battery, which I've had, it depends on the failure mode of the reg/rectifier

    You're on the right track with all of your troubleshooting, start with simple ideas before moving onto more complicated ones
     
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    Last edited: Apr 3, 2020
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    BTW - you can test a thermostat, open the housing and take the thermostat hang it on some wire and immerse it in some water which is on the stove coming to the boil - that's just in case you've got the original which is failing and the gods of spare parts have not smiled upon you and you've happened to get another one which is failing - very unlikely
     
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  13. Brandon Otte

    Brandon Otte Active Member

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    Can I go from the thermostat housing straight to the frame or do I need to tie it into the loom?
    Thanks again I'll have to wait for the lockdown to be end before I can do anything though but at least I can hit the ground running.
     
  14. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    The earth can be hooked up anywhere, to the engine or to the frame, best off on the frame, and use some dielectric grease in between the ring terminal and frame to stop corrosion
     
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  15. Brandon Otte

    Brandon Otte Active Member

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    Yup will do, was my thinking when I bought it too - just didn't want to open the housing without having a spare one handy.
    I'm sure it's unlikely both are faulty but worth a try.
    Just thought would the radiator cap have any play in this - it doesn't push water into the overflow excessively or anything though so probably shouldn't complicate things.
     
  16. Brandon Otte

    Brandon Otte Active Member

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    Awesome thank you! All these ideas to play with just wish I had my bike here with me. It's only 5 minutes up the road but lockdown says I'm not allowed too :(
     
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  17. Brandon Otte

    Brandon Otte Active Member

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    @GreyImport @ruckusman @my67xr

    Hi again guys hope you're all well!

    So I've had a stroke of genius and bought myself a 'budget' coolant temp sensor, with which I plan to test what temp my bike is actually getting to independently of the stock gauge.

    Today I opened my spare(original) thermostat housing with the plan of testing the operation of the thermostat and to fit the new temp sensor for the gauge I've purchased.

    So interestingly enough, as shown by the photos below, the previous owner had removed the moving/sealing part of the thermostat so as to have it open all the time. That indicates to me he's had previous issues - he did mention that ''the temp would rise in sitting traffic''.

    Any how I've fitted the sensor and re-assembled the housing just keeping the open thermostat for now.
    I plan to wire the gauge in properly, temporarily, to test the operating temperature.

    A few questions if I may: What temp should I be expecting?
    Is anything between 85'C-100'c a normal operating range? The gauge is numbered.
    And do you know what the high or red zone of the stock gauge would be in degrees celsius?
    I'm expecting the gauge to not be affected by the lights being turned on and off as the stock one does.

    So if the temp is confirmed to be too high, would that indicate a bad or poor flowing water pump?

    IMG_4204.JPG
    IMG_4205.JPG
    IMG_4206.JPG
    IMG_4208.JPG
    IMG_4209.JPG

    Thanks a lot, hope you don't mind me tagging you in my posts.
     
    Last edited: Apr 12, 2020
  18. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    The water pump is a very simple device and is not likely to be the cause of problems unless the bearings are completely destroyed or air is leaking into the pump. The radiator itself is the most obvious culprit. It may be 30 years old. Temperatures are not shown in the service manual?
     
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  19. Brandon Otte

    Brandon Otte Active Member

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    Ahh okay, yeah I was wondering after posting that I've watched a few videos on water pump replacement and doesn't seem like something that will 'slow its flow'.

    What would you recommend?

    Shall I remove the radiator and flush it out or flush the whole system, how would you go about flushing it?

    Cheers
     
  20. Andych

    Andych Senior Member Premium Member

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    It may not be the water pump... generally a faulty water pump would be noisy or leaking... Other potential issues are blockages in the water passages, corroded and or partially blocked radiator, blown head gasket etc.
    Generally removing the internal of a thermostat only creates more issues, like excessive wear when cold or even running too cool.
    These bikes really need to have all the air bled from them or they will be a real PITA with overheating...

    Dont get too hung up on a particular item being the cause... you may end up chasing your tail... try to be methodical in all your tests etc.
     
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