This process is the same regardless of motorcycle, scooter, moped, or lawn mower.
1. Find the arrow on the outside of your flywheel. If there is not one, make one using a sharpie, scratching a line, etc. This is your flywheel reference mark.
2. Make a piston stop tool. I'm assuming you don't have access to a lathe. The recommended way is to add an insert made of brass to an old plug but if your moped uses a short reach plug (and I think most do), you can go buy a long reach plug. I don't remember which is which, but for example if you use a B7ES, go and buy a B7HS. The threads and everything else will be the same but the plug (threaded portion) will be longer. If this doesn't work, the worst case is you can carefully bend the electrode straight so it will hit the piston.
3. Remove spark plug
4. Rotate flywheel so the piston is somewhere past TDC. Doesn't have to be exact, you just don't want to hit the piston when installing your piston stop tool.
5. Install piston stop tool
6. Rotate flywheel clockwise, slowly, until it stops.
7. Mark lightly on the engine case, right next to where the flywheel arrow is.
8. Repeat 6 counter-clockwise.
9. Repeat 7.
10. Mark exactly half way between these two marks. I recommend using a piece of paper along the outer edge of the flywheel. Mark both case markings on the paper. Fold the paper in half using the two marks and this is half way between the two. Mark this permanently on the case. This is TDC. This is a better method than using a dial indicator because is deals with dwell (I'm not going to go into that).
11. Remove piston stop.
12. Determine which way your engine runs. Look at the fins on the flywheel. They are scooped to grab and push the air. You will be measuring before TDC, so the opposite direction that the flywheel spins.
13. Measure the recommended amount before TDC using a timing wheel. It's different for each cylinder and especially performance cylinders. Typically, performance stuff is set closer to 18 or 16 deg and stock is 18, 19, 21, 22 etc. Depends on the bike etc. If you don't have a timing wheel, measure the diameter of the flywheel. For example, is your timing should be set at 18 degrees, Multiply pi x diameter x 18, and divide the whole amount by 360. Measure this many mm opposite the direction of rotation of flywheel from the arrow and lightly mark.
14. Align the arrow on the flywheel to TDC marked on the engine case.
15. Dont move the flywheel and use the mark from 13 to mark the engine case. Label this 18deg BTDC.
16. Put in spark plug and start bike.
17. Using a timing light, look to see where the arrow on the flywheel is in relation to the 18deg BTDC mark.
18. Remove the flywheel and rotate the stator the proper direction to make the flywheel mark and the 18deg BTDC mark align.
19. Your done. This is the only way to properly do timing with electronic ignition although you can do the above steps with a dial indicator although there are many reasons why I don't recommend it. I've done it both way and this is much easier and more accurate. If you need additional visual help go to
This method assumes you have a marking on the flywheel and on the stator already. Don't rely on them. They are not correct because of manufacturing tolerances.
Hope this helps.