Valve adjustment every 5k for how long?
12-22-2009, 08:00 PM
#22
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Getting tight is not a good thing to be seeing. If the new screws and nuts doesn't clear this up, your seats or valves are wearing fast. The seats may be wearing, or the valve is wearing or cupping. Either way the head will have to be rebuilt it something with the valves or seats are wearing.
As far as noise with this style of valve train, it will never be quite. It should not be tapping real loudly, but should sound more like a sewing machine.
As far as noise with this style of valve train, it will never be quite. It should not be tapping real loudly, but should sound more like a sewing machine.
12-22-2009, 10:30 PM
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First thing I would have recommended is don't run the exhaust valves "tight" to begin with. Fact spec is what... .012"?
Tight exh valves wil run hot, stretch, and require frequent adjustments.
You can always run loose then tighten up, but once you're too tight, you can't reliably go back.
Tight exh valves wil run hot, stretch, and require frequent adjustments.
You can always run loose then tighten up, but once you're too tight, you can't reliably go back.
Last edited by abecedarian; 12-22-2009 at 10:33 PM.
12-24-2009, 01:42 PM
#25
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If you had to run tight on valves just to get them to shut up, one of a couple things has happened:
...the valve stem has pitted or mushroomed where the adjusting screw contacts it, which a feeler gauge will not tell you.
...the rocker shafts or rocker arms are themselves worn and the noise is caused by the arm hitting the shaft when the cam goes to open the valve.
One should consider 'everything' in the valve train.
...the valve stem has pitted or mushroomed where the adjusting screw contacts it, which a feeler gauge will not tell you.
...the rocker shafts or rocker arms are themselves worn and the noise is caused by the arm hitting the shaft when the cam goes to open the valve.
One should consider 'everything' in the valve train.
12-24-2009, 02:48 PM
#26
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On the adjusting screw, they always tend to "dent" or flatten very slightly where they contact the valve stem, it's normal. If the bottom of the adjustment screw was "pitted", that would be unusual. Sometimes the dent, if you haven't adjusted the last for a long time, will get a little deeper, and when you make your adjustment, it will happen end up right on the very edge of the "crater". When that happens the valve will usually smash the small contact area which will cause the lash to increase slightly and make that rocker clatter very soon after your adjustment.
I think my extra adjustment is simply tolerance differences in the rockers themselves and possibly just my own inability to very accurately "feel" the lash gap. But whatever it is... I can usually get the rockers to sound pretty "even" sounding.
gNARLS.
I think my extra adjustment is simply tolerance differences in the rockers themselves and possibly just my own inability to very accurately "feel" the lash gap. But whatever it is... I can usually get the rockers to sound pretty "even" sounding.
gNARLS.
However, I have a Honda CX500TC motorcycle and one of its design flaws is that the valve adjuster screws cause the tip of the valve stem to 'mushroom' and there is no easy way to adjust the valves properly since the feeler gauge itself covers the pit in the end of the valve stems.
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