WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

Need piston for 502 which has flat skirt and 2 rings, I tried later 504/505 piston and the port timing is off

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

This motor (very rare)

http://www.newsachsmotor.de/bis_50_ccm/502/111-1178_IMG.JPG

The piston has a flat skirt

Re: WTB Sachs 502 piston

What do you mean by "flat skirt"? Do you have a pic of the old one?

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

The base of the skirt has no windows or indents. the old one is in the dip tank in an effort to free the rings which will probably not happen It is 38mm diameter, 12mm wrist pin, about 29mm from center of pin to edge of top, 54mm top of dome to base, 51mm edge of dome to base

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

piston picture

IMG_0070.JPG

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

It is for this rare DKW 508 worth making great again. I tried a newer sachs piston but gurgle fest port timing wrong

IMG_0066.JPG

Re: WTB Sachs 502 piston

I checked my Sachs stash. Nothin'

Sorry....

Re: WTB Sachs 502 piston

Probably Fred /

Start with fine sharp offset pick in ring groove working ring a little at a time getting pb blaster under ring, don't force the ring but a try few mm at a time.

leave it set until the next day if/when it stops coming out but make sure pb blaster is underneath it so some more ring will loosen up.

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

I have been soaking and picking for days. Not much matter anyway, there is a chunk off the bottom of the piston. This is some rare shit because my usual guys in Germany didn't have and said it is rare there too

Re: WTB Sachs 502 piston

did you check with mike da bike/ fat city mopeds?

i really doubt he's got it but worth asking

the ring is probably standard, i'd dig it out at all costs, break it into pieces then clean it up and replace.

i saved a very rotten L-ring puch piston a few years ago, heat with a bernzo torch and pry it out in chunks.

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

Rings are not the problem. They are standard 38X2 FG rings. The piston is broken. There is a chunk missing. I need a replacement or equivalent dimensions. I tried a standard Sachs 504 piston, and the distance from the pin to top is shorter, so the port timimng is off. It spits fuel back through the carb,

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

Someone has one of these motors sitting in some dusty attic or a basement behind some boxes of old books. There has to be one left somewhere to be a donor for the little guy.

Re: WTB Sachs 502 piston

I found this on ebay typed in Sachs Piston ....sorry no link i cant figure out where to find it on the app....

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Re: WTB Sachs 502 piston

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

This looks possible! I emailed the dimensions to the seller (fingers crossed)

Thanks

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

That listing says it fits the Sachs Pony 48. That has the 50/2 which is a totally different design that the 502. I had a 50/2 before and I think the piston may be different.

Re: WTB Sachs 502 piston

It says 37.95mm for the diameter ....hopefully it will work...

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

I have a piston in there that is the same diameter. The issue is the distance from the center of the wrist pin (gudgeon pin for the Brits out there) to the edge of the top. The newer Sachs pistons have more dome, but the distance to the edge is shorter. That exposes enough of the intake port when it should be closed all the way, blowing back fuel and robbing power.

Re: WTB Sachs 502 piston

I photo eyeballed all the other measurements....shes close and has the cigar....

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

On the way from Italy. It will be a while for sure. Wish I could find somwething in the USA that fits in the meantime so I can ride the stupid little thing.

Re: WTB Sachs 502 piston

if this does not work i can get a new piston for you

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

The pistons listed above from Italy are NOT correct. None of the ebay listings have the right one. They are the same as the one I tried and are 1mm too short from the wrist pin to the top. The picture I drew shows the correct dimensions. Anyone have a 502?? I know this is rare, but striking out in Germany is troublesome.

502.JPG

Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

Fred, do you really have one? Nobody else seems to.

Re: WTB Sachs 502 piston

♣Slew Foot♣ /

i have a weird Sachs piston its supposedly an overbore for a d cyl.

it looks identical it is 40.05mm dia.

i have to calibrate it to check the other measurements

Re: WTB Sachs 502 piston

...Damn...

Re: WTB Sachs 502 piston

Is there anyway you can use a spacer or thick base gasket? Or am i thinking in the wrong direction?

Re: WTB Sachs 502 piston

♣Slew Foot♣ /

sorry dave mine has the intake cut outs

Re: WTB Sachs 502 piston

....German Ebay.....?....but they all seem to have different motors.... I randomly searched DKW hercules mini mofa.... Maybe a better search on the german ebay would get something...lets just set up a forge and hydraulic press close by and start making forged pistons worlds fastest indian style....

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Re: WTB Sachs 502 piston

...

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Re: WTB Sachs 502 piston

Tri-ped Dave O.D.B. /

LOL thanks. It looks like the missing chunck is not near any ports. I have had the thing soaking in the parts cleaner tank for a week. I am going to try to heat again and pluck off the rings. Wish me luck!

Rich yes you are thinking in the opposite direction. I am thinking though that if Sle Foot's piston has the same top measurements from the pin to the top edge (Which I think is 1mm short because the standard D 505 is so) I would bore the cylinder to 40.05 and riiiiiip!

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