Motor Locking Up While Trying To Start


3 replies to this topic
  • music man

Posted April 17, 2009 - 07:13 AM

#1

new to the forum
i have a 2001 yz426 used from a friend when trying to start the bike after decompressing while kicking the motor wants to lock up
i took the screw cover off the lower unit and freed it with a ratchet and tried it againg done the same thing . any ideas

  • Mark Grant

Posted April 17, 2009 - 07:16 AM

#2

It's time to take it apart bro. That's the bottom line, if it were mine.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • fenderbmxer86

Posted April 20, 2009 - 04:27 AM

#3

If it has an outside Cam chain adjuster try doing that before you open it up. My 450 cam chain got so loose that i thought my crank locked up. We pulled the whole thing apart to find that the cam chain had about 1" of play and binded as i was kicking.

  • Mark Grant

Posted April 20, 2009 - 06:11 AM

#4

If it has an outside Cam chain adjuster try doing that before you open it up. My 450 cam chain got so loose that i thought my crank locked up. We pulled the whole thing apart to find that the cam chain had about 1" of play and binded as i was kicking.


What I have noticed is that when the cam chain is stretched that badly it also does damage to the cam chain gear on the crankshaft, similar to what happens with the drive chain and sprockets. Once the teeth are sharp and bending over it's time for a crank shaft. This is just what I have noticed in the last few high hours motors we've dealt with.





Related Content

Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.