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KX 125 no kickstart or idle

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My bike all of the sudden decided to stop running. overgapped a plug, it fouled and now won't start. Rejetted, cleaned out the carb & power valves, not sure what to do. Now, the bike will start up by only roll starting. Runs through gears fine(in powerband) but when let go, motor dies. Bike won't idle or start by kick. I NEED HELP ! :lol:

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Also, before all this happened his bike ran fine. He shut it off to take a break the other day and when he went to start it again it would not kick over. We did all the basics today like he listed including draining the gas and put a fresh mix in it, and checking the reeds. They looked brand new. The bike has a ton of power when its roll started no bog at any point or sputter. We're pretty stumped, I am going to pull off the top end and inspect it saturday. Any help will be greatly appreciated.

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yes it can. low compression makes it hard to start also , pull the pipe off, look inside the cylinder and see if the piston is scored or showing signs of blow by or ring failure.

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Awesome thanks man. That was our plan this weekend. If nothing it damaged (piston,cylinder wall, ect...) do you think it will be okay to just replace the rings? Hes kind of on a budget.

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yea clean cylinder w/a scotchbrite pad and wd40, get new rings and gaskets (cometic) and you will probably be ok. You will want to check the piston w/a digital or dial caliper for wear and you will need the manual for the specs. The manual will also give you torque values for reassembly. Remember that a 125 cant take a lot of hours on a piston, so you are risking a major failure by not knowing exact age of piston. Unless the previous owner showed you reciepts of a rebuild than i would assume the motor needs a top end.

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Looks good from my perspective, my piston only has one ring? It's not like a typical piston, it doesn't have the 3 layers of rings, i only saw one. there aren't any missing, it's just the way it's designed.

Nothin bad though(cracks/ scrapes), looks good

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Oh, i wasn't sure if the guy that rebuilt it just got some knock off. Has blowby though, could that be the whole problem?

Yes that's most likely your problem it's time for a new piston, there not that expensive and if you taking it apart to install new rings you're better off doing a full top end.

By the sounds of it the previous owner has done a top end (not recently mind you) and the bike now has a wiseco pro-lite piston installed. That's the reason for it only having one ring, so it creates less drag with the down side of losing compression sooner. Most 2 strokes run two rings at least they do from what I've seen.:lol:

When you say it doesn't have three ring's it's because it's not a four stroke and doesn't need the extra oil control ring. For obvious reasons it's meant to burn the oil. :)

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Just a quick update. We took the top end off and sure enough a piece of the piston was broken off right under the ring allowing blow by. The good part is we found the problem. The bad we have to split the case to find the missing piece of the piston.... :lol:

I will get him to upload a picture of the piston in a little bit so you guys can see it.

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