KLR250 thread

Discussion in 'Thumpers' started by Bad Company, May 10, 2008.

  1. rossoe

    rossoe Adventurer

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    I agree don't take yours off! I might have to try an extractor bit I guess.

    Interestingly similar sensor is mentioned here - they mention many hack it to be manual as they don't trust it as when if fails the fan stays off.
  2. XDragRacer

    XDragRacer Long timer Supporter

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    "Not exactly," I think. Fan is controlled by the thermal switch mounted in the lower radiator. No connection with temperature gauge or sensor.
  3. rossoe

    rossoe Adventurer

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    Ah I see, so this sensor just trips a light on the speedo unit?
  4. greasyfatman

    greasyfatman Long timer

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    I have a temp gauge, you have a light? Is the Euro dash different?
  5. rossoe

    rossoe Adventurer

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    no your right - just checked we only have temp gauge. still learning about this bike! having never ridden her I'm not used to looking at the dash.
  6. XDragRacer

    XDragRacer Long timer Supporter

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    Clarifying (even for myself!), the KLR250 as-built has two (2) temperature "sensors," one might say. A water temperature sending unit is mounted in the cylinder head, connected to the temperature gauge. A thermal switch is mounted in the lower radiator, connected to the fan motor relay. Never do these twain meet; independent and separate circuitry.
    greasyfatman likes this.
  7. rossoe

    rossoe Adventurer

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    So I could technically ignore the fact I have no temp reading and rely upon the radiator thermal switch to kick in if it get's too hot, but it's risky in case that fails too and I boil the poor thing!
  8. XDragRacer

    XDragRacer Long timer Supporter

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    If you're concerned about the operational automatic functioning of your thermal radiator switch, you can connect a single-pole single-throw (normally off) switch between the lead to the switch and ground, affording you manual control of your fan. A parallel indicator light (if you choose to install one) will let you know your fan is on.

    Don't think you'll need a temperature gauge to tell you your radiator is boiling.
  9. nails1

    nails1 Been here awhile

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    Maybe sorta-kinda related: on my road bike, I installed a dash light to say when my fan is on. (Yeah, usually I can just hear it, but not always.) I don't know whether the KLR fan is more obvious because my KLR still isn't running. But I have been making (slow) headway on my shop!
  10. XDragRacer

    XDragRacer Long timer Supporter

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    Here's an image of my KLR250 manual fan switch and fan activation light:

    [​IMG]

    Totally superfluous, IMHO, with functioning fan thermal switch.
  11. CliffElam

    CliffElam OldN00b

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    I had a dead thermal switch *and* a dead relay, so $100+ to replace them. I pulled the power/ground wires up into the dashboard wiring harness and attached them to, IIRC, the headlight circuit. Anything past the key will turn the fan on when the key is turned. I live in Florida, so no idea if this would be a bad idea in the great frozen north. Honestly, I want a second fan that also always runs!

    Also, if the thermal sensor on the head is dead/bad, you can buy a radiator cap temp sensor for $30 at an auto-parts store. Do be careful because if there is a circulation problem (water pump breaks) your engine temp will be one thing and your radiator temp another.

    -XC
  12. rossoe

    rossoe Adventurer

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    I'm getting to the point of giving on my old 87 KLR it's first oil change since I picked her up, I haven't even run the engine yet as the tank was completely full or rust, so I had to clear that out and seal it all. After taking off the carb it was also full of brown petrol deposits, and rust particles - pretty grim!

    I'm considering using 'Liqui Moly Engine Oil Flush Shooter' before I drain off the old oil. But just wanted your thoughts on using a flush on an older engine? Odo says it's done 19000 km but I suspect it's had a new engine, as serial numbers do not match frame.

    I'm assuming a reasonable 10-40w semi synth would be fine to use on this age bike?

    XDragRacer I like that fan switch, might make one of those myself.
  13. nails1

    nails1 Been here awhile

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    I hope to be there this winter or fall. I'm still building my garage/shop.

    Mine has a plastic tank, but the old gas turned all the gaskets and plastic parts into a gel substance that was hard to clean out. The petcock was toast. The carb needed a sonic bath, and when I put it back together the float valve leaked too much to start the motor. I've never heard it run, but I do think it was well maintained.

    That's where I quit, and the bike has just been sitting on the back porch.

    I think those flushes are for after a rebuild, primarily to "condition" newly machined surfaces and new bearings. I'd recommend a flush with clean oil and some SeaFoam instead. Some folks are fond of Marvel Mystery Oil additives, but if it shifts okay I think this is a waste of money.

    Synth oil just lasts longer so you can go longer between changes. I'm a fan of Rotella diesel oil: T4 (dino), T6 (synth) or T5 (a mix). Use T4 for any SeaFoam flushes, maybe for the first few changes until the oil you drain out isn't too skanky. Don't use car oils.

    Buy the weight listed in the book. Winging it can lead to shifting problems.
  14. rossoe

    rossoe Adventurer

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    SeaFoam sounds good - perhaps a little slower at cleaning, which might be a good thing on older engines!

    I'm just hoping the engine didn't have too much damage from all my tank rust! as I just discovered my pet cock filter had a hole in it letting all the crudge flow into carb :(
    upload_2020-6-11_14-20-59.png
  15. 8gv

    8gv Long timer

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    My tank was rusty like the one seen in the above picture.

    I used the electrolysis method to clean it.

    It came out great.
  16. XDragRacer

    XDragRacer Long timer Supporter

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    The "Fan On" indicator light remains a useful mod; however, I wouldn't go for the manual switch again unless I had doubts about my thermal switch. Reason: Manual switch appears redundant to an automatic thermal switch.

    These KLR650 videos may be useful in cleaning and adjusting the similar KLR250 carb:

    https://www.klrforum.com/how-tos-tech-guides/19026-carb-overhaul.html
  17. rossoe

    rossoe Adventurer

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    I tried the same re electrolysis - it's first time I ever played with that method - worked ok but still needed a dose of rust eating gel that I swilled around inside after spending 3 days waiting for electrolysis to do it's thing. I ate through 2 graphite anode's before moving onto just using a long chunk of metal.

    IMG_20200308_102836_resized_20200612_110403330.jpg

    I was surpirised at how quickly the internals of tank flash rusted soon as you dried it out after above treatments - you have to work quick to seal it all up!

    Tank is pretty much ready to go now after good coating of tank sealer:

    IMG_20200312_084405_resized_20200612_110159489.jpg

    Just have to buy a new pet cock and paint the outside rusty bits.

    That's a good collection of Carb vids XDragRacer - I found a few on Youtube and have mine all cleaned up ready to go, took a bit of scrubbing to clear out - and I'm still unless one of the tiny holes is clear and air compressor didn't seem to be getting through, but I'll see how it goes. I was surprised many people take the back of the bike frame apart to get at carb, I found it came out ok after removing the coolant tank on the left side.
  18. 1994klr250

    1994klr250 Long timer

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    Anyone have recommendations for a good replacement clutch kit? I was looking at EBC CK4446 with the spring kit CSK148. Other than that I've only found the OEM kawasaki parts.
  19. laylow3down

    laylow3down dirt bike mike

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    I would buy the parts separately...I went with the oem steels and fibers and the EBC heavy duty springs.. all parts obtained from Ebay..
  20. 1994klr250

    1994klr250 Long timer

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    Did you notice any extra effort to use the clutch with the EBC heavy duty springs? The clutch on the 280 big bore kit engine that I put in my friends klr back in 2017 was slipping in the upper rpms. So I had a spare engine that we did a swap on his bike so now I have the 280 engine on my work bench. I'm going to replace the clutch components and then put a set of my early model 1986 klr 250 higher lift and more duration camshafts in it. I'm still bummed out that cycle works racing closed up. I got one of his last 280 kits in June 2017 and I was planning on a 300 or 330 kit in the fall of that year.