YZ400 cam timing


2 replies to this topic
  • Team Wheezer

Posted February 27, 2016 - 09:02 PM

#1

Hi All - new to this and thanks in advance for your help. I searched around a little, but did not see the exact answer I am looking for so here is my issue:

 

Performed a top end rebuild with new timing chain, hot cams exhaust cam with decompression, valve grind, new piston rings, etc. After reassembling and timing per the manual (and help from this forum), the bike will not start. Tried everything with no luck. Pulled the valve cover off to check timing and timing marks look as it should per manual and this forum. However, when looking at the lobes on the opposing side of the cam, the lobes are at 8 and 2 o'clock rather than to 10 and 2 which seems to be "normal". image1.JPG image2.JPG It looks like the intake lobes are off by 90 degrees??

 

Is it possible that the timing gear slipped on the cam? I am perplexed...

 

 



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

Posted February 28, 2016 - 07:20 AM

#2

The intake cam sprocket has slipped on the cam.  You'll need to replace the cam.  Was there any evidence that is seized in the head?



  • Team Wheezer

Posted February 28, 2016 - 08:54 AM

#3

Grayracer - thanks for the reply! That is what I was afraid of. It is weird - there is no sign of the cam seizing. It turns freely in the journals when torqued down and there is no sign of scarring on the cam on the journals. I will get another cam - now I am worried about it seizing as well...

 

At least the mystery is solved - thanks again!







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

The "going back to the other darkside" adventure... by Monk


Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  113 replies
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
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.