Valve Shim Size Questions...

[Stahlgrau333]

Checked the clearances on my valves this past weekend, and it turns out that 7 out of 8 of my valves have 'negative' clearance...could not spin the tappet at all on the back side of the lobe. My measurements were:

I1 - 2.70 - <0
I2 - 2.65 - <0
I3 - ?? No Number - <0
I4 - 2.60x - <0

E1 - 2.60 - <0
E2 - 2.60 - .05mm
E3 - 2.70 - <0
E4 - 2.65x - <0

Obviously, they're way out of spec. My guess is that they've never been adjusted before (bike has ~ 21k miles on it).

My questions are, first, how many sizes should I go down on the 7 that need adjusted? Should I go down one shim, or two? Doing a search here on the forum leads me to believe I should go down 2 sizes, I just want to confirm before I do so.

Second question is, what's the difference between a 'normal' size shim (ie, 2.65) and an 'x' size (ie, 2.65x)? Are they interchangeable, or do I need to do something special with those valves?

Apologies if these are stupid questions, just want to make sure it's done right...

 

[Guest]

Shims

Shims

I believe you are correct in trying 2 sizes below the existing shims and may end up wanting a half step lower. The X designation seems to cover a shim that is outside the spec for a standard shim. ie: a 2.60 shim appears to have a range of 2.59 to 2.61 when new thus a 2.60X will likely be 2.62 or 2.63. At least that is what I have observed to be the case. Ray

 

[Agemax]

buy,borrow,steal a 2.50 shim and fit it in each position. then measure the gap with your guages and work out what size shim is required

 

[Nessism]

I'd order 5 each of sizes 2.55, 2.50, 2.45. Z1 Enterprises sells shims for about $5 each. They won't go to waste and you will have what you need for the next two checks, maybe longer. After that, trade shims with Ray to get what you need.

 

[cowboyup3371]

Two words - Steve's Spreadsheet.

Send him an email and it will help you figure that out.

 

[rustybronco]

After adjusting your valve clearances I have three words for you... leak down test.

Here's a link to a roll you own version> http://www.motorcycleproject.com/motorcycle/text/leakdown.html

the reason to check cylinder leak down you say? how about this... http://thegsresources.com/_forum/showpost.php?p=1238313&postcount=64