WR450F '2008 and '2011 blocking the start and burning starter motor

4 replies to this topic
  • piwtorak

Posted December 14, 2014 - 06:31 AM


Hello Guys...

I have searched this forum, but what I can read about the problem when this 2 bikes stops and the starter motor do not get works, and the kick starter is so hard is this was a problem of the past 2003 2004 bikes... but I have experienced this without solution, my cams of my 2011 was changed for hotcams cams with decompression pin rounded when original is squared, this modification turn better the start process but now I have this again the bike when stops cakes the engine even with the kick starter is so hard to start the bike. is this the famous woodruff problem ? I do not change anything in the right side of the motor adjusting some screw like mentioned for 2003 2004 wr's.


some idea to solve this ? I have burned 3 starter motors already because when the engine stops this way the starter motor can not turn the engine, after some strokes in the kick starter it frees and the bike turns on quickly....


hoping find a solution for this...


thanks for help..


  • GuyGraham

Posted December 14, 2014 - 08:06 AM


When the engine stalls, it sometimes stops just past when with the auto decompresser closes, and hence the starter motor cannot turn the engine over and it cannot be kick started either


The solution is to  rock the backwards, with it in gear, so the engine goes in reverse slightly

This lowers the piston in the bore and, reverses the cam rotation so that it is in a place where the auto decompresser will work

The engine will now turn over with the starter motor


I have stalled my bike many times, and pressing the starter button does nothing and it is impossible to kick it over either

The above solution never fails to allow the starter motor to turn the engine over

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  • piwtorak

Posted December 14, 2014 - 08:58 AM


Thanks GuyGraham..


I had hope to find some heal for this, but I can see now is a without solution problem..

I will survive with this.

I am curious because I had 2 WR250F 2007  and no problem like this occurs...is only 450F have this ?



thanks for reply and help..

  • stevethe

Posted December 14, 2014 - 02:44 PM


Look for the decompression pin to stick out about 2.55 mm. With a hot cam.
You also must take out the little gear from the case when putting in a new starter motor.
You should not be having problems if everything is done right.

  • GuyGraham

Posted December 15, 2014 - 11:05 AM


A 450 engine has a lot more compression than the 250, so possibly this doesn't happen on the 250.

The 450 starter motor is very small (light weight) when compared to say a DRZ400 starter motor - hence it does not have as much power to turn the engine over.



If you just try to force the engine to start by keep pressing the starter motor, it will just burn it out


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