Help!!


5 replies to this topic
  • YZ450F4

Posted March 25, 2011 - 02:17 PM

#1

Today i installed my new head pipe because the other on had cracked. i took it out for a ride and it was running great. just like it always has. i stalled the bike out and i was like you know no big deal. went to kick it and it has an a** load of compression. when you compression stroke it and kick it, it will kick back like a 2 stroke. Please help im clueless. it was just rebuilt 5 hours ago with new piston, cylinder, and stainless steel valves.
Thanks

  • grayracer513

Posted March 25, 2011 - 02:41 PM

#2

Start by checking the cam timing. If the chain was kinking, it could have backed over the exhaust cam when you stalled it.

  • YZ450F4

Posted March 25, 2011 - 05:20 PM

#3

its late so il have to check the timming tomorrow; however, i did replace the timming chain also in the rebuild

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • howard113

Posted March 25, 2011 - 05:32 PM

#4

Today i installed my new head pipe because the other on had cracked. i took it out for a ride and it was running great. just like it always has. i stalled the bike out and i was like you know no big deal. went to kick it and it has an a** load of compression. when you compression stroke it and kick it, it will kick back like a 2 stroke. Please help im clueless. it was just rebuilt 5 hours ago with new piston, cylinder, and stainless steel valves.
Thanks


i hope with those valves you got the spring kit and i hope you got your valves seats cut.if not,those valves will wear way faster then they should and if you didnt get the right springs and stuck with oem,your going to have floating valves.....

  • YZ450F4

Posted March 28, 2011 - 10:08 AM

#5

the valves were pro-x and they came with springs. timing is right on the money; however, motor has metal shavings!!!! crank bearings

  • YZ450F4

Posted March 28, 2011 - 10:09 AM

#6

crank bearings starting to seize maybe?





Related Content

Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 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
Forums
Photo

YZ450F 03 Sparks driving me crazy by SirAttard


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 5 replies
Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 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.