Won't kick through stroke (426)

10 replies to this topic
  • Pozi

Posted October 15, 2004 - 06:33 AM


While at the Florence dune a month ago I started noticing problems with my 426's engine not running as smooth as it should occasionally. When I would jump the engine would die right as I landed. It did this a couple times until finally it wouldn't start any more. And now when I tried kicking it the kickstarter will not complete the stroke. It stops about 2/3 through the kick.

....So I have the engine almost torn down looking for some obvious signs of trouble. Any suggestions as to what it might be and what to look for?

One other thing....I think maybe my hot start was "stuck" on because the Dr.D hot start cable was broke. And the little dirt/sand kept it from turning off.

Please help

  • Ga426owner

Posted October 15, 2004 - 06:44 AM


mine did this once on my 2001 - I thought it had seized - I roll started it in 2nd or 3rd gear it started and never had the issue again - I think the decompression or exhaust valve stuck for a minute..
I can not tell you if this is the case for you - but may be worth a try..

  • Pozi

Posted October 15, 2004 - 11:10 AM


Interesting. I never thought about one of the valves sticking. I did not try to push start it once it happened.

Since I have the engine "almost" torn down (case not split yet) should I continue and split the case just to be sure?

  • sirthumpalot

Posted October 15, 2004 - 03:16 PM


Guess it's too late to check the timing, but that would have been my first task. If the cam chain jumped then the valves may have hit the piston.

In liu of that, if you already have the head off then carefully spin it over. If it turns freely then the problem may likely have been related to the head/valves. If it's still locked up then the problem is in the bottom end somewhere, keep disassembling. Remember to inspect as you go. It could be as simple as a broken part getting stuck between the clutch and crank gear.

  • YZ250F_Rider

Posted October 15, 2004 - 03:47 PM


replace the timing chain. then look at the float setting.

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  • YZDAD1

Posted October 15, 2004 - 05:09 PM


If the crank "turns over" with the top end disassembled, the lower end should not be the issue. With the top end off you can also check the con rod (make sure it's not siezed on the big end bearing) This is common especially if a water pump seal leaks and is not immediatly attended too. Usually an out of time condition (valve issue) or bad rod bearing causes a partial rotation condition. Siezed mains would be a total lockup condition...unless maybe a broken main bearing race? :cry:

  • moto2000

Posted October 15, 2004 - 05:42 PM


Would your bike kick thru completely if you did it slowly or with the plug out? :cry:

  • Scooter426

Posted October 15, 2004 - 08:55 PM


mine did this and it was the big end of the rod. the bearing cage failed and scored the crank pin and rod. I am in the middle of fixing it right now. Check your oil/filter for any aluminum dust or bronze dust. It will be quite obvious. Mine was all in the oil filter. The motor initially locked solid, and then I was able to free it. I then tore it down.

  • Pozi

Posted October 18, 2004 - 05:49 AM


Would your bike kick thru completely if you did it slowly or with the plug out? :cry:

Interesting you asked this because it kicked through just fine with the compression release leaver pulled in. Separated the cases and everything looks good with the exception of a little pitting on the con rod where the piston pin goes. Is this ok to leave this way?

  • moto2000

Posted October 18, 2004 - 10:49 AM


I asked this because if you have the idle turned up too high, you won't be able to kick it thru a complete stroke. It will go 3/4 and stop....feels like you'll break your foot or the kickstarter. Hearing that you had hotstart problems(why it was stalling out), I thought it was possible you tried turning up the idle too far. :cry:

  • 01yz426

Posted October 31, 2004 - 11:47 PM


Hope you got er figured out by now..

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