Valve Clearance question


5 replies to this topic
  • G-BRO

Posted July 14, 2014 - 01:57 PM

#1

Question for all of you-

When you are re-shimming valves what clearances are you aiming for?

Example- Tolerances are .20-.25mms. Current measured clearance is .18mm.

Are you going to reshim for .23ish mm to be in the middle range of the tolerances? .25mm to allow for the valve to tighten after more wear? Or anything in between? Does it matter?

I have my valves shimmed for the looser limits, but since then the bike has developed the famous valve "ticking" sound. Wondering if this is the cause and if I should reconsider my approach.

  • grayracer513

Posted July 14, 2014 - 02:14 PM

#2

The whole range, from tight to loose, is only .002", so it doesn't much matter, but technically, the ideal is the tight limit of the specified clearance. 



  • G-BRO

Posted July 14, 2014 - 02:26 PM

#3

Ok thanks for the reply. For what reason is it better to have them on the tighter side?

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

Posted July 14, 2014 - 02:31 PM

#4

Oh and one more thing. If you have a higher performance cam such as a Hot Cam, does it become more important to have them on the tighter side?

  • mdsharon

Posted July 14, 2014 - 07:10 PM

#5

Oh and one more thing. If you have a higher performance cam such as a Hot Cam, does it become more important to have them on the tighter side?

They will probably just tighten over time so I go right in middle of tight.



  • grayracer513

Posted July 15, 2014 - 06:48 AM

#6

The reason that the tight side is technically better (and why Yamaha uses shims in .01mm increments to achieve it) is that with less clearance, there is less impact between cam and lifter on opening, and, marginally, more net lift.







Related Content

Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies
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
Motocross

Thinking about Yamaha 250... by Arctic Pride


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 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.