I think I killed my 125!

KTM · 04-10-2011, 02:53 PM

Sorry to post 2 threads so close together but I really need help 2004 KTM 125sx- I was riding through an open field in third gear and all of a sudden the bike started to cut out and it slowed it self down and then died. Now when I try to kick it over it feels alot harder to kick and when it fires I can hear a metal clacking sound. Something obviously broke but what would be the first thing you would do? Pull the head? I think maybe I worked it to hard without letting it warm up in the lower gears.

bajadog · 04-11-2011, 07:08 AM

What is the bike 2 stroke or 4 stroke?

If 4, drain oil and see what it looks like, and what is in the
pick up screen. Then pull left side clutch cover, and inspect.

2 stroke I would pull the pipe out of the head and see
if you can see the piston. Then pull the head and cylinder.

nightrodjc · 04-11-2011, 08:10 AM

Pull the exhaust. Get a flashlight and look in the exhaust port to see what condition the piston and ring is in. Top is going to have to come off to repair top or bottom.

KTM · 04-11-2011, 11:37 AM

I pulled the top end off and everything looks perfect. What could be the problem in the bottom end that would cause symptoms like hard starting rattling and hard to kick? I was thinking maybe the crank bearing?

WoodsRiderParts · 04-13-2011, 08:18 PM

Could be the crank bearing. It could also be a bad oil seal that just decided to give up life. I have had that happen before. How does the plug look?

Luke