04 yz450 valve questions


1 reply to this topic
  • thumpyz

Posted March 06, 2008 - 08:19 PM

#1

Well, right now my steed is down for other reasons, so i am doing some preventative maintenance. I am checking the valves(my first time, on my first 4 stroke) and i just have a few questions. When finding tdc, my punch marks line up perfectly,but the I mark is about 1/8th of an inch forward of the mark in the case, According to the manual this is not right. Does this mean my timing is off? Also one intake valve is "tight". It is measuring at .076mm. Does this kind of wear seem normal? Any and all help is greatly appreciated.:thumbsup:

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted March 06, 2008 - 08:58 PM

#2

Line the I (not the "H" that is just to the left of it) up first, then check your cams. The cams turn at half speed, so the crank moves quite a ways without moving the cams that much.

When you look at where the cams are with the crank lined up, and they don't line up perfectly (and they probably won't), ask yourself what moving them one tooth would make them look like.

Your tight valve means one of two things:
> The valve has moved into the seat by a very small amount, and if you adjust it, everything will be fine.

> The coating on the valve has worn through, and if you adjust it, it will be tight again within 6 hours.

Shim the valve and check back after the next ride or two. If it hasn't moved, your OK, if it's already tighter, then it's time for a valve job.





Related Content

Forums
Photo

Snake pit oct 30th by The Anvil


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

James Stewart back on a YZ450F by YamaLink


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

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
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
 
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.