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Carb damper oil

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The owners hand book says the oil should be 1/2 below top of piston. The 1970 HD carb tuning service sheet, if the damper is vented the oil should be 1/2 inch above the top of the piston (paragraph 8 for those reading along). All the other books (Haynes and others) do not mention this difference. Am I reading this wrong?
 
Don't know about the discrepency, as long as there is enough in there to damp the motion of the piston throughout the range will be OK, if too much it will leak out and burn off and be ok, if not enough it will stutter on acceleration, add a little more and it will be OK.

I have never measured it, just poured a little as needed and no problems.
 
HI- I was always taught to use the piston damper as a dip stick,oil at right level when you insert piston damper and feel resistance there should be1/4 inch between bottom of screw thread and top of casing,
 
I think the above advice is good. The "top of the piston" is actually the top of the vertical inner tube which extends above the piston but is below the outer housing.

Almost everything from very light oils to 50 wt motor oil has been used. The lightest that can be used without stumbling will give the best throttle response & fuel mileage. Each engine may require something different for optimum performance.
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zblu said:
Always used "Singer" sewing machine oil in mine, probably a 10W oil

I remembered you writing this the last time I was at Wal-Mart and picked up a bottle. We have the carbs off to detail and replace the connecting fuel line.
 
As a matter of interest, my car runs very well with no oil in the dampers. Just enough in the bottoms of the H6 carbs to provide lubrication for the damper spindle. Very fast, crisp throttle response. This - with 4 oz. piston return springs.

It's a good idea to match the return springs exactly for tension so that both carbs lift exactly the same amount for a given throttle setting.
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