Sachs 505/2 engine help

Adam Rosenow /

Hey all!

So this morning I stumbled across an ad for a "Pegasus Rocky" moped. Never heard of it before, but I recognized the iconic Sachs clutch cover and thought back to my first Clinton moped fondly. I went to check it out and after chatting with the seller, agreed to a sale (now the fun begins).

The motor turns out to be a 505/2 speed manual transmission (pardon my failure of nomenclature). From what I can find, it seems like this bike might be as rare as the Pegasus it is named after... great! Also a bit frustrating due to lack of easily obtained information... All that said, it's got a lot of potential to get back on the road with a little help!

So here's the old gurl's issues!

1.) The twist shift is completely missing both the cables necessary to change gears, and I'm not having much luck seeing how they connect or any clear diagram of their connection.

2.) The starter clutch cable has been replaced at some point, bypassing the decompression valve. Im wondering if that's an issue? Is the decompression valve actually a necessary component? Can I leave it bypassed, or should I somehow finagle it into use again with a custom cable?

3.) Twist grip throttle is missing. This is not much of a big deal IMO, easy enough to hit the local used parts shop. Unless I'm not seeing some crucial deviation from the norm as far as these being relatively universal?

4.) Missing airbox (typical).

Any sagely wisdom from our crew of Sachs fan-boys would be greatly appreciated! I'll try to snap some more/better


photos tomorrow to show y'all what I'm working with.

Thanks in advance,


Re: Sachs 505/2 engine help

I was wondering who bought that! I know nothing about it..was thinking about asking on here....keep us informed, this is a neat looking bike, manual trans you say? Cool!

Re: Sachs 505/2 engine help

There's info on the Wiki.

1) There is 1 cable from hand shifter goes to gear selection on the back part of the engine 1 cable that goes to the clutch.

2) No you don't need the decompression valve but you will need a cable to the clutch or you won't be able to shift it.


Re: Sachs 505/2 engine help

Adam Rosenow /

Thanks for the info guys! I got in the garage tonight and did a quick burn through of the fuel and ignition system. I also ran through the wiring harness and re-routed that so it would open a clear shot to the shift lever from the ONE (you called it spudley!) cable mount located on the front of the engine. It looks like it only needs one cable to shift between gears, but the twist grip has 2 cable slots (see photos)?? What am I missing?

I did a lot of cleaning as well, but still have to hit the local shop for the throttle tomorrow. I'll leave the decompression valve bypassed for now, maybe play with that another day once I've got her running again.

Thanks again for the help I appreciate all the info I can get! As promised, here are some photos of the sweet gurl!

P.s. found the engine plate! 505/2B


Re: Sachs 505/2 engine help

Adam Rosenow /

More pix


Re: Sachs 505/2 engine help

Wow i've never seen a 505/2 setup stock before pretty cool.

So maybe I worded it funny in my last post but there will be 2 cables running from the shifter grip to the engine. 1 will run to the gear selector, 1 will run to the clutch.

The cable running to the clutch will be attached to what is normally the left hand side brake lever. Sachs rear brake is a coaster brake so only the right hand side is a brake lever. Left hand is now your clutch.

The cable running to your gear selection will be in one of the other two positions on your handlebar. It probably has two so it can be used on different bikes that would use a push/pull style cable setup.

You have it hooked up wrong right now. Looking at your pic:

A: looks to me like this is where the clutch cable might be routed?

B: This is your clutch arm. The end of the clutch cable will connect to the little arm behind the carb.

C: THIS is the gear selection arm. You need to connect your gear selection cable here. IIRC you pulling it toward the front of the engine for 1st gear and letting it spring back toward the rear of the engine is 2nd gear. In the middle is neutral.


Re: Sachs 505/2 engine help

Re: Sachs 505/2 engine help

Adam Rosenow /

Such great info! Thank you!

I think that the second cable mount may be for a push pull system like you describe. The shift lever is spring loaded, so the "push" function seems redundant in this specific application.

The twist grip can only be moved when the clutch lever is pulled, so it seems to me like the clutch lever/ cable setup is run correctly (despite the bypassing of the decompression valve). I intend to pick up the throttle grip tonight, and work on some custom cabling to get the shifter functioning too. I'll update y'all tonight on progress. Thanks a ton!


Re: Sachs 505/2 engine help

That’s a really rad bike you got, great score!

Re: Sachs 505/2 engine help

Sweet! Spudley nailed it. I've spent alotta time on sachs and especially love the 2 speeds, I just built one a few weeks ago and rebuilt the clutch for 7 piece and recalled on another last night!

Spuds right. The 2 cable slots on shifter are for other push pull, same controls fit zundapp, x50, other grip shift mopeds.

The cable stops come off little tabs on the intake. You've got the clutch run correctly I think. In the pic above that got marked up, A is the old decomp- i recommend removing that and plugging with a m10 bolt. You can also ignore it, but to be correct, on the manual motors it connects just to it's own small decomp lever, like the choke lever. B is correct, bottom tab on the intake holds a barrel adjust/cable stop and goes to a knarp at the clutch arm. That's connected to the clutch lever (left side where brake lever would be, again as spuder sez)

C is the shifter gear select arm. The grip shift cable goes to a stop also on the intake, and cable goes under the frame to that little gear select lever. With the grip shifter fully released, that arm sits all the way back in 2nd gear, adjust cable tension so when the grip shifter is in N it pulls that gear arm a little way forward and outta gear, and all the way pulled it drops to 1st.

Another note, the engine you have has the shorter "A" length crank, all the wiki stuff for 505/1a performance applies. Some later 505/2bs had the longer D stroke, but indicate 49 not 47cc on the engine plate

Re: Sachs 505/2 engine help

Wow Will surprised it took you so long to make an appearance in this thread :)

Re: Sachs 505/2 engine help

I just got one of these motors and I got some parts laying around, How do these do with performance parts?

Re: Sachs 505/2 engine help

DrGeorgeTompson (Alan) /

> nigel peyton Wrote:

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

> I just got one of these motors and I got some parts laying around, How

> do these do with performance parts?

i built one with the 80cc athena kit and TM24. Had a bunch of trouble with the clutch but was able to add an extra spring and another plate and pad and it did pretty good. I tried very hard to not slip it a whole bunch to get the bike moving to keep the plates from glazing. I think the clutch handles torque ok, but they tend to have trouble and slip/glaze with a lot of revs.

With a mild kit and pipe, I think they would be a very good engine.

Re: Sachs 505/2 engine help

'sup nigel, hit me up if you need, whenever.

Alan nailed it. I have almost exactly the same experience and would give the same advice. I did an athena 80 TM24 build on a 2 speed too, and it glazed with high RPM. I was able to get it under control with tall gearing and a really expensive hard to get $300 german 9 piece clutch pack (which in retrospect isnt that crazy expensive considering folks'll drop 250 for a puch hammer despite the stock puch clutch being pretty capable...) but seems the 9 piece setups don't exist anymore. Still the 7 piece are around sometimes and work OK. that thing hauled ass, I rode it in richmond a few rallies and it'd get up over 60. But it was awful on gas and brutal on the clutches I went back to basically a stock D 50cc setup, and that was my goto for years, mid 40s and dead reliable.

But yea, a 505/2 w milder build like an airsal, hack pipe, 15 bing and taller gearing - thats a perfect setup for a 50mph bike with good take-off and good reliability.

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