water pump

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cowboyshooter04
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water pump

Post by cowboyshooter04 »

i recently bought a kx 125 ,guy said he just rebuilt top end ,i rode it for an hour or two for 2-or 3 days ,it ran great ,it quit running on me when it was idling & would not start back ,i changed spark plug & still would not start ,it will only start if you hold throttle wide open & kick on it a lot ,it runs fine at high rpm ,but dies at low rpm ,i discovered the water pump wasnt pumping when working on it ,the mounting bolt was missing off the impeller ,it fell off when i removed the cover ,i put a bolt back in it & the impeller still doesnt turn when i kick start it with the cover off ,my question is should it turn when i kick start it or only when the bike is running & do you think i have overheated the engine causing the hard start problem ,, it gave no signs of overheating ,i did a compression test 110psi dry & didnt seem to come up wet ,starting problem maybe unrelated to water pump ??
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KDXGarage
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Re: water pump

Post by KDXGarage »

Hi. I moved your thread to the "Other Bikes" section, as it is not about a KDX. Thanks.

How is the air filter and carburetor?

Also, which year KX125??
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bufftester
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Re: water pump

Post by bufftester »

So many places to start....Yes the impeller should turn when you kick the bike over, it's driven by the crank. What did the pump drive shaft look like, water pump seals? Pics help a lot. 110 is low, manual says to rebuild top end for anything below 116. Either the top end was not done properly (likely) or you damaged it running without a water pump (also likely) or both. Was the bike rejetted after the top end rebuild (required but probably not done)? What mix ratio are you running? You are looking at least at pulling the cylinder and taking a good look, as well as pulling the right engine cover off to find the source of the water pump issue. What's the coolant level like? any changes in it? You may get better response over at kxriders.com (KX only forum) though many of us here own both KX and KDXs and will help if we can. You do have a service manual and torque wrench, right?
cowboyshooter04
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Re: water pump

Post by cowboyshooter04 »

it is a 1998 kx 125 ,air filter a little dirty ,not real bad ,i pulled it out & tried starting it ,it ran the same ,mix is 40-1 ,dont know if it was rejetted or not ,i ran a bore scope down in the cylinder ,didnt see any obvious problems , will post pictures when i get home
what is recommended on rejetting after rebuild ? (just rebuilt my sons kdx ,i didnt rejet it ,it spooges real bad before & after rebuild)
thanks
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Re: water pump

Post by KDXGarage »

BORE SCOPE?! ... cheater. :lol: :mrgreen:

110 sounds quite low.
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cowboyshooter04
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water pump

Post by cowboyshooter04 »

how do you add photos
thanks
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Re: water pump

Post by KDXGarage »

photobucket account or similar
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cowboyshooter04
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water pump

Post by cowboyshooter04 »

removed right side eng cover ,found water pump gear off of shaft ,going to replace water pump & disassemble top end ,hope nothing damaged ,maybe can just replace rings and or piston
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