moby spark timing

Kevin Ibbetson /

I don't have one of those timing devices that screw into the spark plug hole but I do have a degree wheel. Anybody know when the points should open on a '70 40V Mobylette? Just slightly before TDC i'm guessing but how many degrees. Thanks

Re: moby spark timing

it's usually around 12, maybe 15 deg BTDC on most bikes .. THIS break> Mobylette manual says anywhere from 1.5 to 3 mm BTDC for the various models.. Check and see if your bike is listed on the specs page. (page 5)

A little depth gauge is not hard to whip up.. thread a hole in a flat piece of steel or aluminum and secure the thing in position over the spark plug hole.. then screw a bolt or threaded rod down through it until the bolt touches the piston at TDC..

Threads per inch of the bolt can be easily converted to vertical distance. A 1/4" x 20 threaded rod is gonna drop .05 " per revolution. 0.05" = 1.27mm .. So, 2 turns of the bolt is near 2.5mm. (if you use metric stuff, it wont even require conversion)

Re: moby spark timing

Re: moby spark timing

Kevin Ibbetson /

thanks guys, great info, i'm going to file it.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account