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-   Ironhead Sportster Motorcycle Talk (1957-1985) (http://xlforum.net/forums/forumdisplay.php?f=7)
-   -   Ironhead anyone recognize these pistons? (http://xlforum.net/forums/showthread.php?t=2076211)

brucstoudt 28th March 2020 21:16

anyone recognize these pistons?
 
https://www.ebay.com/itm/Harley-Davi...wAAOSwUvBedPrV

doodah man 28th March 2020 21:24

The listing describes that they are forged venolias at .020” over.

ferretface 28th March 2020 22:12

Crank casting says "57" and seller says "These will work on 900s and 1000s 1957-80"...

Isn't that the magneto drive on the right side??? Would this assembly really 'work' on a 1970-1980???

doodah man 28th March 2020 22:20

Quote:

Originally Posted by ferretface (Post 5814103)
Isn't that the magneto drive on the right side???

Those two are the pinion gear (that drive the cams) and the oil pump drive gear.

ferretface 28th March 2020 22:27

Quote:

Originally Posted by doodah man (Post 5814108)
Those two are the pinion gear (that drive the cams) and the oil pump drive gear.

Ah, Thanks! I confuse easily... :p

needspeed 28th March 2020 23:11

I'm not familiar with those pistons and can't be sure but they look heavier than they need to be. Personally I don't like that style of retaining ring.

" These will work on 900s and 1000s 1957-80":frownthre
Seller needs to change this to "These will work on 900s and 1000s 1957-76" ( flywheels only)
True, these will work on all years up to and including 1976 but we know that 900s and 1000s have different advance timing marks.

It's interesting that my '54 to '78 parts book shows the same left side flywheel part number (23916-57A) for all those years. The timing marks on the wheel for sale appear to me to be from a 1000.

ryder rick 29th March 2020 02:29

I thinks those pistons are lighter than stock pistons. I like'em.

mrmom9r 29th March 2020 14:12

Very high compression , that's a lot of dome.

Probably 11 or 12 : 1

Flywheels don't change in the 70's just the shafts. Flywheels don't change until 81.

needspeed 29th March 2020 19:43

Some of the wording in my post #6 may have caused some confusion. :o Mrmom9r cleared some of it up.

I said:
These will work on 900s and 1000s 1957-76" ( flywheels only).

I should have said:
These will work on 900s and 1000s 1957-76" ( flywheel ASSEMBLY minus pistons). Because it's the shafts that make what's being sold only work on '76 and earlier.

I only mention the flywheel number to point out that (by my parts book) if you have a 23916-57A flywheel you may have a 40° or a 45° advance mark?

Pretty sure those are not off the shelf pistons. Somebody had them custom made.

ryder rick 29th March 2020 19:50

I would be very hesitant to reuse those pistons. Being still attached to the crank they may not have been handled with the care they deserve.


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