04 yz450 valve adjustment with hotcams

3 replies to this topic
  • dwnlowx

Posted February 16, 2007 - 04:25 PM


im putting in a set of hotcams and i see a couple different valve adjustment settings,hotcams info says that exhaust valve is to be set at .20mm and intake at .15mm is this correct

also is there any jetting changes i might need to make

is there any break in tips from experience


  • grayracer513

Posted February 16, 2007 - 04:35 PM


Intakes .10-15mm

Exhausts .20-25mm

Cam grinders generally want the engine to be run at more than 2000 rpm for the first 15 minutes of operation to make sure that the cam lubes well during that time.

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  • dwnlowx

Posted February 16, 2007 - 08:20 PM


thanks gray

is tighter better our if there around there dont touch em
im just curious and i need to do it right

  • grayracer513

Posted February 16, 2007 - 08:51 PM


In looking at any such clearance specification, either of the two numbers given, or any number in between them, is within the specified tolerance range, and therefore good. It's well to bear in mind that the entire range of the spec is slightly less than .002" wide, so choosing between the tight and loose edges of the spec is quite literally splitting hairs.

"If they're around there," isn't acceptable. Any measurement within the specified range is. If you could set them to a particular exact clearance, you would choose the tighter of the settings.

Also, While Yamaha OEM and Hot Cams shims are only available in increments of .05mm, Honda sells them in increments of .025mm, so you can be more precise if you've a mind to. Be sure to get the 9.48mm diameter shims, such as those used in a CRF450, if buying from Honda.

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