Cam trouble

3 replies to this topic
  • Speedin' Ian

Posted December 10, 2004 - 07:59 AM


I was puttting my motor back together last night after rebuilding the trans and I noticed after installing the cams that the intake cam does not spin nearly as freely as the exhasut cam. How easy should it be to spin the cam after it is tightened down? Any thoughts on what would cause this? Thanks for the help

  • Chris_from_Oz

Posted December 10, 2004 - 08:06 AM


Make sure the intake cam is seated correctly. Also, proper torque settings on the cam 'caps' are critical to ensure your cams spin freely :cry:

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

Posted December 10, 2004 - 08:53 AM


I had this same thing happen on my 250F. I couldn't see anything wrong with how it was together, so I left it like that and it's fine. Had it apart later, and the bearing surfaces are still OK.

Here's what you should do to be as sure as you can be that things are OK. Check the clearances on the cam using PlastiGauge or similar as laid out in the manual. Be VERY careful when torquing down the cam caps. The manual calls for 7.2 foot pounds, which is 86.5 inch pounds. A lot of people, including myself, think that this is too much for this assembly and reduce the torque value. I use 70-75 inch pounds (6 foot pounds). Use an inch pound wrench and torque it down evenly from the center outward in 15 inch pound increments.

Also be sure you haven't left any of the dreaded "foreign material" (lint from rags, dirt, even a hair) in the bearing saddles, or on the surfaces where the caps mate to the head.

If none of this turns up anything definitely wrong, and you can rotate the cam at all by hand, you're probably all right. Warm it up gently the first time back out, and go back in to check on it later, just to be sure.

  • Speedin' Ian

Posted December 10, 2004 - 08:59 AM


Thanks for the advice guys, it spins freely, just not as easily as the exhaust. I will remove the cam just to make sure there is nothing in the cam seat and go from there.

Related Content


BIGBORE FOR YZ450F 2006? by Taattie94

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

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

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.