To correctly adjust the valves, the valve springs must be removed (L-head engines only) and have the piston at 1/4″ past TDC on the power stroke.
| Model Series | Intake Valve min/max | Exhaust Valve min/max |
| 60000-120000 | .005/.007″ | .007/.009″ |
| 130000-280000 | .005/.007″ | .009/.011″ |
| 230000-240000; 300000,320000 | .007/.009″ | .017/.019″ |
| Twin Cylinder Vanguards 290000, 303000, 350000 | .004/.006″ | .004/.006″ |
| 400000, 420000, 460000 | .006″/.008″ | .009″/.011″ |
| 28N700, 28P700, 28Q700, 28S700, 28U700, 28W700, 287700 | .003″/.005″ | .005″/.007″ |
| 310700, 312700 | .003″/.005″ | .005″/.007″ |
| 85400 | .002″/.004″ | .002″/.004″ |
| 97700, 99700 | .005″/.007″ | .005″/.007″ |
| 104700 | .003″/.005″ | .003″/.005″ |
| 115400, 117400 | .002″/.004″ | .002″/.004″ |
| 138400 | .005″/.008″ | .005″/.008″ |
| 161400 | .003″/.005″ | .003″/.005″ |
| 185400 | .002″/.004″ | .002″/.004″ |
| 235400, 245400 | .004″/.006″ | .004″/.006″ |
| 260700, 261700 | .003″/.005″ | .003″/.005″ |
I have a 21 HP v-twin vanguard it has a fluttering sound kind of like it is missing. It has 130 lbs. compression one cyl. sounds like it is missing at an idle when pulling spark plug wire off but at top rpm its not to noticeable but still has some rumbling sounds. You can take the dipstick out and it blows some oil out. what sounds like the problem. Thank you
Head gasket blowing on one of the heads – ive got the same problem , its easy enough to fix.