Sachs 505 Question

Are the cylinders on the Sachs 505 C&D identical ? They share the same 50.5mm piston and the 85/12/104A carb. The crank is different

Re: Sachs 505 Question

Richard Eberline /

No, The D needs a longer stroke and is ported for Sachs high performance output.

Re: Sachs 505 Question

here's way too much info and speculation...

The crank on the D is longer giving it more stroke and slightly higher displacement plus better compression for more torque. Presumably the "C" is just the better ported "D" cylinder on the shorter "A" stroke.

I've never actually seen a "C" but some have reported they're less aggressively ported than the "D"; however other's have claimed they're the same cylinder. It would make sense to have a smaller exhaust for the C since the 2mm shorter stroke will go down 1mm less far at BDC, but apart from compressions that's the only thing that'd be different. I could also see Sachs just using the D cylinder directly as is, because that 1mm wouldn't make a big difference.

I will say this: sachs pistons and cylinders must match, but crank doesn't need to - for example an "A" piston will not work in a "D" cylinder. "A" and "B" are interchangeable and "C" and "D" are interchangeable.

they don't care which crank it is, as long as you've got a matched cylinder/piston pair. like an A jug and piston works fine on the D crank, (albeit with crappier porting).

I must also add, the bolt holes are aligned differently on A vs B vs D to prevent easily swapping BUT it's super simple to just drill out the holes on the cylinder and swap em anyway.

TLDR: the "C" cylinder may be the exact same as the "D", and it may be slightly more restrictively ported, however a "C" cylinder will work on a "D" bottom end, with the "C" or "D" piston (same piston), and conversely a D cylinder will work on a C bottom end with C piston. C and D cylinders will also work on an A or B bottom end IF you drill out the bolt holes and make sure to also use the matching C/D piston.

Re: Sachs 505 Question

Thank you for the information.It is confusing, I have a Sachs part list that shows the c and D sharing the same cylinder but have read from experienced people that say their different. I pulled the cylinder off because compression was only 25#. The problem was the decomp. The rings were fine but the piston looked like it had sever bites taken out of both sides of the bottom of the skirt on the connecting rod sides

The pston measured 50.5 mm. Dos is sending me a new one .Im having the cylinder honed,can’t figure out how that piston got wrecked ,it has the correct C crank and no pieces were found anywhere.Thanks Again

Re: Sachs 505 Question

If you picture it, the D crank is 2mm longer stroke. that means using it with the short crank it goes 1mm shorter at top (lower compression), and 1mm higher from bottom. so if they had the same ports, the exhaust for the D wouldnt fully open with the C. But the transfer timing is all the same because longer/shorter crank it's same timing in the middle

They have different wrist pin location on the A vs D pistons, so that the piston is higher. if you put the A piston in a D cylinder I think it just slams into the top at TDC, because the piston's taller. So maybe the C vs D piston are different heights despite being same diameter? I doubt it, but it's possible. that might wreck the skirt

Re: Sachs 505 Question

I’m interested to see how the piston from Dos compares to the one I took out.I also sent the wrecked piston to Moped junkyard there going to match a new piston to the wrecked one.The part number for the C& D piston is 0286-378-051. The part number for the D 505 cylinder is 0213-146-286 I haven’t been able to find a part number for the 505 C cylinder ,which makes me think their the same. Thank You

Re: Sachs 505 Question

♣Slew Foot♣ /

If it was a d crank running an A cylinder I got a piston for that. I also have a Sachs first overbore piston and two A jugs.

Re: Sachs 505 Question

Dos is sending me a new piston for my 1C, however I took the clutch apart and the two sprin washers were pretty flattened out . Moped junkyard had one so I’d like to find another ,I bent the other two and they seem to be working. This $300 bike is probably going to cost me $1000.00. There’s a guy on my local Facebook marketplace

Selling a Honda Hobbit for $1050.00 with 300 miles that runs and is museum condition. I’m having fun though and learning a lot about how these iconic machines run. Hopefully I’ll find another when this ones finished. Thanks Again

Re: Sachs 505 Question

♣Slew Foot♣ /

Seriously the clutch ain't a big dealio.

I have lots of clutch parts...

Re: Sachs 505 Question

> Tim Doll Wrote:

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

>This $300 bike is probably going to cost me $1000.00.

Cheap bikes usually don't stay that way . ;)

Re: Sachs 505 Question

♣Slew Foot♣ /

Mine was a non titled frame $75

Ending price w title functional + but not pretty. 750.

Re: Sachs 505 Question

That $4000 Supercub is looking more reasonable everyday,they are awesome machines but in my neighborhood I’d probably get shot and have it stolen the first day.

Re: Sachs 505 Question

> Tim Doll Wrote:

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

> That $4000 Supercub is looking more reasonable everyday,they are awesome

> machines but in my neighborhood I’d probably get shot and have it stolen

> the first day.

Sounds like you should invest in a new neighborhood rather than a new bike . :)

Re: Sachs 505 Question

You got that right !

Re: Sachs 505 Question

♣Slew Foot♣ /

If u look and act crazy...

They get out of your way. And lock their doors at stoplights...

Re: Sachs 505 Question

I've got lotsa random sachs parts, though i've been thinning out alot. there's a thing in toledo end of the month people swapping lotsa parts, you can almost definitely find whatever you need and cheap.

I'll dig through the sachs pile tonight see if there's any clutch bits

Re: Sachs 505 Question

Thanks again , the swap meet in Toledo sounds like fun.Im glad to have the bike in this condition , cosmetically it is good with no missing body parts . Mechanically it’s a surprise in every box. I’m taking almost everything apart but careful to mark everything and take plenty of pictures . My main concern is the wiring. I fear having everything mechanically sound but having a wire or two misplaced.

Re: Sachs 505 Question

luckily it's relatively simple and worst case you can just hardwire it to have functional lights horn and of course to run without needing any of the original harness

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