Help !! What's wrong with my bike

Joined
Oct 13, 2017
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#1
Hello I've recently bought a cr125 , I was on it and it seemed abit flat and then I changed the spark plug it went like a bad out of hell for about 15 mins then it stopped when I was going really slow went to start it and it wouldn't start on the kick only backfired after about 10 . It bump started and I ride home however now it won't kick start it only backfires after a few kicks ? It will start on a bump to make sure the fire triangle is there !

I was talking of the head to see if the rings had gone while there I was training the coolant to my surprise nothing came out ,out a drop in and it leaked out a small hole under the casing behind the water pump turbine it couldn't have mixed with the oil ?

Ino I'll need a water pump seal and bearing but what else will I need to set this bike right ?
 
Joined
Jul 27, 1999
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#2
You'd be well served to check all the basics. Pull and measure the cylinder, check the rod and crank for wear, measure the piston and rings, check the reeds etc. With a used bike it's best to assume everything is worn out until you measure and prove otherwise.
 
Likes: The Redrider
Joined
Jun 14, 2019
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#4
From what I could gather, it sounds like a tired motor. Pull the rotor cover and wiggle that puppy, if and up down play, its the big end bearings, side to side is ok. Next get your shop manual and do a top end, don't scrimp, purchase everything, install em correctly and torque it to specs. Hint never use gasket sealer, and carefully clean all mating surfaces. Clean and oil that air filter. Buy 91 octane gas and mix it correctly. buy a fresh ngk spark plug and go from there...