MZB ignition timing difficulties w/Sachs B motor

[pklinck]

Folks,

The instructions to set the timing with the MZB ignition system are pretty straight forward; Using a dial indicator, "move the piston for ex., 2.4mm BTDC and line up the red stator plate mark with the mark on the rotor flywheel and then tighten the nut" and you are good to go, in a nut shell.  Then we would check the timing with a strop light to see where we are on the marks while it was running.  We were always off.  When we set the marks, the strop light results were always different.

Problems:

1.) when you tighten the flywheel nut, it advances the timing even more.
2.) I've heard of info with several suggested BTDC marks in MMs; 2.0, 2.4 and 3.2mm.  The book says 2.0mm BTDC.
3.) How precise does this timing need to be on the sachs B motor?

Let me know any precise details that could help me out on this issue.  We used a dial indicator down the spark hole.

peter


peter klinck

[paul a. busick]

Pete,  I have a similar ignition on my PE.  I had a hard time getting it in time also.  What I ended up doing was to make an adjustable plug to fit the spark plug hole. Found TDC. bottomed the plug to that point.  Removed plug, adjusted plug so that it extended 2 1/2 MM. Replaced plug and moved piston against plug.  You can now hold the piston position by in engaging a gear and holding piston against plug by rotating rear wheel. You should now be able to tighten crankshaft nut with out any movement. Don't use plug against piston as a stop when torquing. Hold the fly wheel with a suitable tool. I have not used a timing lite on my set up. But it runs just fine.  If the motor kicks back more than normal when kick starting, reduce the advance a half MM at a time  until it feels correct.  Remember- this is not a road racing motor where you are splitting frog hairs. Also listen for ping and knock .  Too much ping and knock - back off the advance a bit more. Hope this is of some help.  Amherst Paul

[pklinck]

Ok, thanks.  i'll try to hold the rotor still using a strap wrench, rather than just tightening it up.  So it slipped I think.

thanks,

peter klinck

[Lew Mayer]

When you put the flywheel on, you need to strike it into place with a deadblow mallet to set it on the crank, then tighten the nut.

Lew Mayer