paul karpenko Posted September 29, 2019 Hello everyone I bought a 2006 ktm 250xc and the previous owner fully rebuilt the whole engine and it had plenty of compression, I broke the bike in and then took it to sand mountain, after 2 days of ridding I had lost all my compression and I can move the kick starter with 1 finger but the bike starts up right away between 1-3 kicks and has a lot of power, overall the bike runs strong but it just feels like there’s no compression, anyone have any idea of what it might be ? Thank you. Share this post Link to post Share on other sites
CRJohnny My Rides (2) Posted September 29, 2019 Unfortunately your finger is not a compression tester 2 Share this post Link to post Share on other sites
Ievko82 Posted September 29, 2019 (edited) 12 hours ago, paul karpenko said: Hello everyone I bought a 2006 ktm 250xc and the previous owner fully rebuilt the whole engine and it had plenty of compression, I broke the bike in and then took it to sand mountain, after 2 days of ridding I had lost all my compression and I can move the kick starter with 1 finger but the bike starts up right away between 1-3 kicks and has a lot of power, overall the bike runs strong but it just feels like there’s no compression, anyone have any idea of what it might be ? Thank you. I can move the kick starter on my 300 easily if I let it go real slow, but try to push it down fast as if starting it and you'll probably break your finger. I dont know about the 250s but the 300s have a hole in the cyl that let's some compression leak out at kicking speeds maybe this is what your feeling. Edited September 29, 2019 by Ievko82 Share this post Link to post Share on other sites
paul karpenko Posted September 30, 2019 I used the finger as an example, what I’m basically saying is that it feels as if there’s no compression what so ever, zero resistance Share this post Link to post Share on other sites
Ievko82 Posted September 30, 2019 3 hours ago, paul karpenko said: I used the finger as an example, what I’m basically saying is that it feels as if there’s no compression what so ever, zero resistance Even if you push down on it fast? Share this post Link to post Share on other sites
Spud786 Posted September 30, 2019 Either you sucked dirt and damaged motor parts, or the motor was wore out, and previous owner did a Half A$$ rebuild. Regardless , will have to tore it down again for inspection. Share this post Link to post Share on other sites
Doc Brown Posted September 30, 2019 7 minutes ago, Spud786 said: have to tore it down again for inspection. Agree, but I'd measure compression before tear down just to see how low it is. If it's very low you had realized that while riding.... 1 Share this post Link to post Share on other sites
MrKTMrider Posted October 8, 2019 On 9/29/2019 at 12:51 AM, paul karpenko said: Hello everyone I bought a 2006 ktm 250xc and the previous owner fully rebuilt the whole engine and it had plenty of compression, I broke the bike in and then took it to sand mountain, after 2 days of ridding I had lost all my compression and I can move the kick starter with 1 finger but the bike starts up right away between 1-3 kicks and has a lot of power, overall the bike runs strong but it just feels like there’s no compression, anyone have any idea of what it might be ? Thank you. I've seen guys suck sand into the airbox destroying the motor. Start with a compression tester. Like mention above. Might only need a fresh ring job. Share this post Link to post Share on other sites
