Low compression / Sticky valve on 05 YZ450F

25 replies to this topic
  • grayracer513

Posted December 04, 2007 - 10:57 PM


I suspect a heavy carbon build up on the backs of the valves. Assuming you gave your measurements in English units, a clearance excess of .004" isn't enough to let the shim jam as you are suggesting, IMO.

  • BC3

Posted December 05, 2007 - 09:03 AM


Yeah after thinking about it your probably right.....What do you suggest for
the carbon build up.....

  • BC3

Posted December 05, 2007 - 09:26 AM


Maybe some products out there that can remove the carbon?

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  • grayracer513

Posted December 05, 2007 - 01:27 PM


Maybe some products out there that can remove the carbon?

Not by name off the top of my head. Go back to this:

there are "top engine cleaners" that do a good job. One of the best available is from the GM parts counter, imaginatively named "GM Top Engine Cleaner". But like all over the counter GM chemicals, it's pricey. Most TEC's are basically the same stuff as "Techroline", and are already present in the fuel you use in small quantities.

  • BC3

Posted December 05, 2007 - 07:40 PM


Sounds like I will be taking a trip to the Chevy dealer tomorrow.....

Thanks, BC

  • BC3

Posted December 09, 2007 - 03:39 PM


I just got back from a weekend at Stonyford and 450 ran perfect. Started good
all day and was perfect. I used the Seafoam the day before we laft and the
stuff really works.....Thanks Guys.....


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