Sachs 505 CDI timing, please help me.

So I jut bought this Sachs balboa for $125 with a seized motor, this is my first ever moped, but I do have experience with engines and things like that. I started by taking off the cylinder head and un-seized it, everything was fine the piston was just a little rusty, so I bought a new one from treat land and installed it. (It looked a little different than the one I pulled out, is that ok?)

Now I'm getting no spark, so I went back to treat land and bought, as well as a bunch of other treats :)), I have no idea about the timing on this thing and I tried looking through older threads, but couldn't find anything, anyone out there who could help me out

Messed with the suspension a little ;)


Re: Sachs 505 CDI timing, please help me.

The ones treats sells are A pistons. Meaning you put an A piston in a D engine. As it says in the review on the page you bought the piston from, you can use an A in a D but it will not perform as well as the original.

The only part of the old piston that could be rusted was the rings, the pistons themselves where aluminum. Buy a proper 38X1.5FG top ring and put the original piston back in it. Use one of the 38X2FG rings from the A piston for the bottom ring.

I don't know why you bothered to buy the CDI package. You have what looks to be a perfectly serviceable points system already. At most you've have to replace the points and the condenser if they are completely screwed up. Look on this site and the wiki, you will find how to set points (which is dead simple) and determine if the condenser is bad.

Re: Sachs 505 CDI timing, please help me.

First rule of mopers... don't just throw money at it. Figure out the issue, research the wiki and/or search the forums. If no answer and no knowledge of what to do check one of the facebook "lover's of _____ mopeds" pages then ask here. Generally the Sachs guys are a bit more laid back and will give you less bullshit. Don't know why but its true. And on that note...

...second rule: Ask ALL your questions IN THIS THREAD. keeps the drama down from making a shit ton of new threads every time you have a question that's been asked before.

Back to your issues... the A pistons can be trimmed to get close to the performance spec of what an actual D piston would give you. As far as the ignition... should have kept the stock points setup. No use tossing on a cdi if you cant even troubleshoot a points setup.

Re: Sachs 505 CDI timing, please help me.

yea probably just needed the points cleaned or the taillight wire grounded and it woulda sparked.

anyhow those cdi's are pretty easy on sachs, the stator basically centered seems pretty spot on usually. However those cdi's are cheap and pretty unreliable, i'd much prefer running the orig points.

timing between 15 and 18 degrees btdc is good. use a timing light if you wanna time the cdi, it's easier to use a drill and 17mm socket on the flywheel nut to turn it over so you can time it without the bike running.

Re: Sachs 505 CDI timing, please help me.

Rich Swingewood /

Hey Wizards Josiah McCoy,

Do you know the details on trimming the piston to match the D type?

I've looked about buut can't find any info on trimming the piston, I have ground a 45 degree angle on the piston exhaust port side but have not tried it yet.



Re: Sachs 505 CDI timing, please help me.

Technically you cannot match other pistons to a D piston but you can trim them back to allow clearance of the transfers etc. I do not have any pics but check the wiki. I believe Will D or one of the other gents added a bunch of info on the differences between all the Sachs 504/505 engines. The info itself is either in there or a link to a thread is.

Re: Sachs 505 CDI timing, please help me.

Like said above,use a timing light for getting the spark right.I use the inductive(simplest and cheapest to use) to ascertain exactly when the spark arrives. Just clip it over your spark plug wire and power it from a 12V battery.So simple. don-ohio (:^)

Re: Sachs 505 CDI timing, please help me.

Thanks for all the info guys, I'm thinking I'm gonna just service the points it would be less work, thing is... I cut all the wires

Re: Sachs 505 CDI timing, please help me.

Why did you do that? On your piston clearance pull cylinder forward enough to see the case face. Turn crank and see if piston skirt clears case ,if it does OK, if not case will have to be opened up. Trimming piston may affect transfer ports. Best to go back to original piston

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