Sachs 505 1C

Tim Doll /
barneyfife
Feb 03, 2020 01:18PM

Should there be any play at all when twisting motion is applied to the connecting rod against crankshaft ? When I bought this bike I removed the cylinder and their were big pieces broke off the piston skirt, they were in the crankcase. I’m wondering why this happened, checked all part numbers and they were correct. The 1C shares the same piston,connecting rod ,cylinder and carb as the 1D ,only the crank is different.

42mm on the 1c and 44mm on the 1D. I got a new piston and had the cylinder honed and am a little concerned about it having another wreck , trying to find out if anyone knows what could have happened. Thanks

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Re: Sachs 505 1C

Born to be WillD /
willd
Feb 03, 2020 02:19PM

not sure what you mean.

If the conrod points down like this

The conrod can flop side to side some, that's not bad. in and out though, like along the line of the cylinder, is bad and might indicate missing bigend rollers.

but I think you're talking about the prior, side to side, and that's ok

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Re: Sachs 505 1C

P D /
pdcomm
Feb 03, 2020 03:28PM

> Born to be WillD Wrote:

> -------------------------------------------------------

> not sure what you mean.

>

> If the conrod points down like this

>

> The conrod can flop side to side some, that's not bad. in and out

> though, like along the line of the cylinder, is bad and might indicate

> missing bigend rollers.

>

> but I think you're talking about the prior, side to side, and that's ok

Just to clarify : the rod should be able to slide side to side a bit , with little if any addition play at the small end .

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Re: Sachs 505 1C

Tim Doll /
barneyfife OP
Feb 03, 2020 03:46PM

I’ts not moving in and out ,I just got a little play when twisting the piston end of the connecting rod back and forth, like across the width of the rod. Thanks

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Re: Sachs 505 1C

Frank Cisneros /
antihifi
Feb 03, 2020 06:00PM

Side to side is fine. In and out is bad news.

There’s a lot of space in the crank case itself for piston chunks to sit in and not do too much damage. If piston got stuck in your crank shaft itself I would imagine you would see much more damage than what you’re describing.

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Re: Sachs 505 1C

Tim Doll /
barneyfife OP
Feb 03, 2020 06:18PM

The cylinder was not scored bad was able to have it honed , just can’t figure out how the rod slapped both sides of the skirt. I don’t know if a timing or ignition snafoo could cause that kind of damage. Maybe the oil mix wasn’t right, we’ll be trying to fire it up pretty soon. Thanks

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Re: Sachs 505 1C

♣Slew Foot♣ /
thewhitedog
Feb 11, 2020 04:11AM

A piston & cyl run on a d crank?

Measure the stroke.

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Re: Sachs 505 1C

Tim Doll /
barneyfife OP
Feb 11, 2020 10:34AM

The piston,cylinder connecting rod and carb are the same as the 1D and I can tell the engine has never been taken apart. Thanks

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Re: Sachs 505 1C

Born to be WillD /
willd
Feb 11, 2020 04:52PM

it's kinda hard to measure the stroke because the plug hole isn't straight on and you can't remove the head with 1 piece jug. The engine tage even if it doesnt say ABC orD will say 47 or 49cc - 49 is the 44mm stroke D crank. The quickest check if you suspect it's been maybe swapped, if it's a square C/D cylinder, look up into the exhaust port at BDC and if the piston hangs over the bottom by ~1mm it's probably the shorter crank.

It's awkward trying to measure stroke outside the bike with the jug off. The other telltale if you have the crank outta the cases is the location of the bigend bearing - on the D the bigend rod lines up right next to the taper on the cheeks, the ABC 42mm crank the bigend is close to the center of the cheeks with some space before they taper off. Search for crank diffs or look in the wiki on sachs motor differences for photos

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