Yz450 Kick Sart Locked Up.help Please

8 replies to this topic
  • csl590

Posted May 27, 2006 - 10:20 AM


I have a 2003 YZ450 that I was riding and all of a sudden it cut off and when I tried to kick it it was real ruff and then the kickstart locked up.So I thought it was crank bearings so i tore the engine down and couldnt find anything wrong. Put it all back together it cranked 2nd kick Idled there for about five min. and shut off and the kick starter locked up again. So I thought maybe the compression release is stuck so I took the plug out and it still wouldnt move. So then I took the crank cap off and turned it over fine by the crank and then the kick start would move again but then locked up again. So before tearing it down again i was wondering if you brilliant bike guys would give me some insight and help thanks,Chris

  • 984

Posted May 27, 2006 - 09:07 PM


if decompression is spot on, check valve clearance. i had the same thing with my crf450.

  • FriscoKLR

Posted May 27, 2006 - 09:38 PM


Sometimes when I try to bump start mine and don't get enough speed to start it or hit the kill switch and roll it to a stop the kick start will lock up. Can just let the clutch out and roll it forward a few feet to fix that though.

When you let it idle for 5 minutes, did you shut it off or did it just quit running. Just letting it sit and idle that long will get it really hot, hopefully you didn't seize it up.

  • John407

Posted May 27, 2006 - 09:55 PM


My '03 does that (locks up) once a year or so. I just put it in gear and rock it forward a little. It's worked for me every time so far. Do not try to kick it thru, this is when the kick starts are getting broken.

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  • csl590

Posted May 28, 2006 - 06:46 PM


I appreciate everyones response, I was just wondering if anyone new what causes this so i can save my self some time on fixing it.It makes since about how to get it to work again but I would like to fix it if I could.Thanks,Chris

  • 984

Posted May 28, 2006 - 06:56 PM


it sounds like your hotstart or valves? sometimes the basics solve these problems. clean air filter and backfire screen, new plug, fresh gas, clean fuel filter, check valves, main jet (all jetting). think back when your bike ran well. what was different. you'll probably solve your own problem.

  • Squishy

Posted June 01, 2006 - 09:28 AM


I had the same issue on an 04 yz450. I tried rocking it and it free'd it up for a moment. Then when I kicked it again it lost all ability to start. Ended up that the starter gear broke... So once it locks up, don't make the mistake I did thinking I can "work it out".

After the gear was replaced and the kick assembly was rebuilt I have had no issues since.

  • Ga426owner

Posted June 01, 2006 - 11:55 AM


I appreciate everyones response, I was just wondering if anyone new what causes this so i can save my self some time on fixing it.It makes since about how to get it to work again but I would like to fix it if I could.Thanks,Chris

Several years ago my 03 did the same thing at a race - I figured it had major issues until 2 other 03 owners told me theirs did it too. I fixed it by roll starting it in 3rd.....it has yet to do it since....I never understood why and have seen probably 5-8 other threads here discussing the same thing...weird

  • SureBlue

Posted June 01, 2006 - 12:20 PM


My '06 locked up once after I stalled it, I just put it in gear and moved the bike forward a bit and could again kick it.
Weird is that my '04 450 had once no compression at all after it had been standing some weeks, I could kick it several times like it was without a spark plug. I guess all this has only to do with a jammed autodecomp system, I'm not worrying too much about it.

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