What model/ year does this piston fit?

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panhead_kicker
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What model/ year does this piston fit?

#1

Post by panhead_kicker »

None of my catalogs have the hand written number found on these piston boxes 22021-48R .030+
Anyone know what model/ year does these pistons fit?
I assume the "R" is for Racing. They appear to be for a 74" motor.
22021-48R
22021-48R
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RUBONE
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Re: What model/ year does this piston fit?

#2

Post by RUBONE »

Look at the bottom of the page. Dow metal for 74 (magnesium). What are your plans for them?
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WR kit for WL.jpg
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panhead_kicker
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Re: What model/ year does this piston fit?

#3

Post by panhead_kicker »

Thanks Robbie!
Pretty cool!! "Hill Climber"
Just trying to catalog a few "unknown" items right now.
Here is the tag from one of the boxes, not sure if it belongs, says .020 fit while box says .030.
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RUBONE
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Re: What model/ year does this piston fit?

#4

Post by RUBONE »

The .020 is piston to cylinder wall clearance! :shock: The Dow metal pistons expand like crazy! Even standard pistons in a racer were fitted at about .010, .008 was considered tight and needed break in!
Very few parts were supplied for Big Twin racing. The pistons, a cam, some gearing (sprockets), a TT frame and oil tank, but not much. Most racing was based on class "C" so it was all 750 SV or 500 OHV.
I don't know for sure when those pistons appeared because they are not in the '48 racing parts catalog. That parts list is from '54. I had originally posted it to show the WR "kit" which appears above it on the page and some had claimed never existed.
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