VALVE ADJUSTMENT

Posted by RodneyCB750K1979 on Apr 08, 2013; 4:36am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/VALVE-ADJUSTMENT-tp4039066.html

I'm trying to adjust valve clearance on a 1979 Honda CB750 Limited Edition DOHC.  The following clearances were measured:

         VALVE  INTAKE EXHAUST
1 Valve 1-1  0.085        0.228
2 Valve 1-2  0.04          0.153
3 Valve 2-1  0.076        0.085
4 Valve 2-2  0.127        0.28
5 Valve 3-1  0.064        0.127
6 Valve 3-2  0.076        0.089
7 Valve 4-1  0.051        0.09
8 Valve 4-2  0.06          0.087
                       
ALLOWABLE: 0.080   (0.06-0.130)
ALL DIMENSIONS mm
April 7, 2013
1979 Honda CB750 Limited Edition

I removed the shim from Intake Valve 2-2 which was showing 0.127mm clearance.  The shim was marked 280.  I installed a shim marked 290.  The clearance became less than .050mm. Out of curiosity, I replaced the 290 shim with a 270 shim and the clearance became 0.229mm. I'm confused. What shim do I need to install?