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still no compression in yz250f


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Hey guys, I've just done a top end rebuild of a 2001 yz250f, replaced gasketsgaskets, as I have done this, I have tdc fine, and valve clearances are perfect, new oil cleaned the carby and fuel lines, new radiator coolant but yet there is still no compression, I can use the kick starter with my hand. The decompression cable is fine and perfect. Why would I still have no comp, it is seriously making me frustrated, please help people.

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the rings are not seated.

 

take the spark plug out.  put 3-5 drops of oil down the hole onto the  piston crown  then 1 squirt of wd40.  and 1 squirt of engine start.

plug back in quick.

 

after about 5 cranks it should really stiffen up as that little bit of oil will seal the rings to the cylinder wall.

 

now you can accomplish the same thing with about 50-80 kicks of the lever because that takes the sharpness away from the ring edge but idealy that needs to be done by the running motor not kick start lever.

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