Kayak 125cc Chinese bike. Troubles

I recently bought a 2015 kayak 125cc dirtbike. It needs a new Piston ring. I can't find a Piston ring that's specificly for it. I was thinking about just getting a big bore for it with a new Piston and everything. But don't know what would match it. Please help

No offense but that's part of the reason why we don't buy Chinese bikes. I hope you find a solution for your issue. Can't you buy that whole bike for $260? Find someone who destroyed the frame or something and buy it as a parts bike and swap parts.

Sent from my SM-N950U using ThumperTalk mobile app

In order for you to get the right parts the first time, you'll need to take your engine apart and measure the bore of the cylinder and the diameter of the wrist pin, for starters. Some 125cc engines have a 52.4mm bore, others are 54mm. There are also two different sized wrist pins: 13 and 14mm. You also need to know the deck height of the piston, as there are a few different connecting rod lengths, making for different strokes.


Dude. A new top end for these things are like 35$ on eBay. It comes with a new piston, rings, wrist pin, and brand new cylinder. And most of them come with new head gasket and top end gaskets

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By M3t
      Hi guys,
      Picked up a 2000 YZ 125 in pretty good condition, but wanted to look into swapping out the Athena Factory kit on there with a OEM cylinder and head.  I know the Athena kit uses their own power valves so I'll need to source the OEM ones, but all the other hardware is the same.  Do power valves wear out, or am I safe buying a lightly used set on ebay for this part?  The cylinder and head I'll be buying brand new.
      Thanks in advance guys.
      Edit: My goal is to basically restore this bike back to nearly new condition.  I’m willing to spend some money, possibly more than it’s worth to some.  Ultimately I wanted a rock solid green sticker 125 to thrash on all year so bear with me.  Small airbox leak by previous owner let dirt into the boot so I’m doing a flush at the bare minimum.  I have not even started the bike since I purchased and did my internal inspection.  Splitting cases soon down the line to check and replace bearings and seals.  
    • By Gary02
      So I am 16 about 155 pounds and want a new bike. my first bike was an 06 crf230f bought it last summer wanted more power within 2 weeks, didn't have money at the time so I just kept riding it. want to go 2 stroke so I can work on my own bike more and just because they r more fun, I have ridden a 250 2 stroke before but it was 93 yz250 and didn't feel all that crazy. Btw I have about 3000-3500 to spend what bike would I be best off with 
    • By Owenfoye15
      I went to do I top end on my bike because the compression felt low and it is now winter so there is not much riding to do anyway. When I took the piston out I noticed a lip had formed on the exhaust port side of the piston. There was no wear or scoring on the cylinder which I found strange. I put a new piston in warmed up the bike at idle with a few blips on the throttle. During this time when ever I would blip the throttle there would be a low quite sound like sand was in my expansion chamber. I blew out my pipe but the noise was still there. I pull the head of to just make sure everything look right after being ran and the piston had a small lip on it again. I've link a picture of the piston that I replaced with the new one. 
    • By 1989YZ125
      Hey everyone, I'm new to the forum here. I apologize if I've posted this in the wrong spot. I've been trying to remove the engine on my 1989 yz125 and have had some difficulty with the swing arm bolt. It's my first bike so I'm not too familiar with the tear down process. I've looked up some videos on how to do it and it seems like it generally requires some heavy hitting while making sure not to screw up the threads or mushroom it all together. However, my bike looks different than all the others i've seen in that it cannot be pushed through to the other side can you pull it out or what? the bolt seems to have a little play so i know its not stuck. I don't have a manual for it and have not been able to find any info online. Thanks in advance!

    • By wtgill13
      Hey all, let me get right to the point, basically for the past couple years I've had this bike, it hasn't been running right. It tends to start well, and has a decent amount of power for a 200+ lb kid on it, but once I attempt to hit the top of the power band, it tends to cough and sputter like it's choking. When I recently checked to carb to jet it, I realized ALL but one of the Jets are missing. I've checked the reed valves, they seem to be in great shape... However, today (it is a warm day) it ran great for a while, after topping off the oil and running with the choke half on, this bike also leaks oil, but I'm almost convinced that this is a jetting issue (being that they're missing)  at this point, but I've also never put a top end in this bike. Thanks for any help, I'd just like to get an opinion on what you guys think.   I know I'm all over the place btw, sorry for that