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kx 250 powervalve problem

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its a 94 kx 250, motor was just fully rebuilt from crank/seals and full top end kit. the bike smokes horribly and 1st-3rd is just bogging and once i get into 4th itl clear out a bit. stopped to take a look and notice the exhaust powervalve linkage cover is leaking oil. pulled the header off and its soaked with oil. im debating if its a crank seal problem or something else? i dont think its burning the gear oil because the plug was fairly clean and theres no oil in the combustion chamber its just in the exhaust ports. is it one of the valve o-rings or something? i had a shop take it all out when the cylinder was plated so was this their screw up? im totally lost here 👍

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It is very easy to roll the trans (right) seal's lip when you put the crank in. You can pull the clutch cover and the primary sprockets and look carefully at the seal to see if it is rolled. You can also pressure test the motor to check for leaks too.

Ed

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when i drained the bottom end i only got about half of the amount of oil i put in. i understand im not gonna get every drop out but i lost a lot of gear oil and being that its not leaking its gotta be going into the head and being burned off. i just dont know how its getting to the head and i dont wanna split the cases again unless i absolutely have to

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If the seal is rolled it will be noticeable with the primary gear and power valve drive gear removed. I have done it before and have gotten away with using a pick tool roll the seal back in place but was worried about it for the first few rides but all was ok.

Ed

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In the FAQ sticky at the top of the page there is a thread I did on case reassy. the 12'th pic shows the seal, not the best pic but good enough, that one is fine but a rolled one will be sticking out about a quarter of the way around. Good luck.

Ed

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ok well the seal appears to be fine, if just lets say the fact that i didnt drain anywheres near as much oil as i put in could it be a fuel problem? im not sure exactly what jets im running and i need new reeds so maybe could it just be too rich and thats why it was bogging 1st- 3rd? maybe its getting enough air flow once i hit 4th and thatts why its clearing out a bit.

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I would still pressure test the motor if it were mine. Check your jetting and change your reeds and see if it helps, you need to do those things anyway.

Ed

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yea just ordered new reeds and when they get in il play with the jetting and see where i can get the motor pressure tested at. hopefully i can get this done soon the little bit i got to ride the other day made me remember how much fun it is on 2 wheels. ive been riding a kfx 700 (fat whore) since feb. and i missed my kx soo much

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