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jalexquijano

Damper oil for Hitachi SU Twin carbs

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Recently purchased a set of round top SU carburetors twin Hitachi HJG 46W. What can i use as damper oil for these carburetors that have been sent dried? WIll 3 in 1 oil work? or can i use 10w 30 nissan motor oil?

Please advise.

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Never thought I'd be one to say this........but, did you bother to type "damper oil" in the search box in the upper right corner of the page? Search is a wondrous tool and opens the door to a wealth of collected knowledge.

Dennis

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I personally use 3-in-1 branded straight 20w motor oil, comes in a convenient little squeeze bottle like the normal 3 in 1 and has a picture of an electric motor on it.

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The damper is simple and you only need to remember 3 things:

1. 30Wt for hot areas, 20Wt for cooler areas (from Mr Matsuo).

2. The oil just dampens the piston from bouncing when going over bumps and from engine vibrations.

3. The oil regulates how fast the piston rises and falls when transitioning throttle.

If the oil is thick, the piston will rise slower and there will be more depression (vacuum/suction) at the bridge and it will pull more fuel from the jet. Think of it as a pseudo- acceleration enrichment circuit. It has the opposite effect on deceleration; with thicker oil it will fall slower and pull less fuel.

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I have used ATF in my carbs for sooooo long I'm still taking it out of a cardboard can...... These really are the world's crudest shock absorber. I've micced enough of them to say with some assurance that there are two different sizes of pucks......so as you are fiddling for your solution play on......

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