02 yz426 cams hard to turn.


3 replies to this topic
  • boomereed

Posted March 22, 2015 - 11:08 AM

#1

Can anyone tell me how easy the cams should turn on the 426 ? Someone worked on this bike before doing shims and I think they over torqued cam bolts and intake cam seized and jumped time and valves hit piston and bent the intake valves. Intake cam is stiff one journal has minor Gaul ding that I've cleaned up with 600 grit paper. Now it turns but still seems stiff.

  • G-BRO

Posted March 23, 2015 - 11:07 AM

#2

Can anyone tell me how easy the cams should turn on the 426 ? Someone worked on this bike before doing shims and I think they over torqued cam bolts and intake cam seized and jumped time and valves hit piston and bent the intake valves. Intake cam is stiff one journal has minor Gaul ding that I've cleaned up with 600 grit paper. Now it turns but still seems stiff.


I had that same thing happen to my 426 on the intake side. Not being a machinist and wanting to restore the reliability of the bike, I sent my cam caps, cams and head to Engine Dynamics in Petaluma CA. The guys were very helpful. They ended up cleaning up the cam journals, cam cap and polishing the head for 175 bucks. I've got about 30 hours on the bike since with no issues.

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

Posted March 23, 2015 - 05:22 PM

#3

Thanks did they tell you what caused it?

  • G-BRO

Posted March 23, 2015 - 06:34 PM

#4

Thanks did they tell you what caused it?


The two center bolts on the cam cap were over torqued





Related Content

Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Forums
Photo
Supercross

Wilson the Blue Privateer by jetfuel


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On Yesterday, 06:20 PM
Forums
Photo

Is it worth it? (Cam and High compression piston) by macgi77


Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 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.