16 H 15 tooth magdynamo drive sprocket

Is the sprocket on the mag itself seated ? Remember it is on tapered shaft and difficult to remove once set home .

Hi Gary,

   Have you got the correct mag mounting platform for your engine ? There are 3 or 4 different off-sets, so you might  have the wrong one on yours.

My guess is the same as Richard, you prob have the wrong platform. I went through that pain! 

Dan

Which year is your engine ? With the change to flat lever followers in 1938 and then later circular tappets in '48, the 'overhang' on the plates extended each time. This means that an earlier plate on a later engine will have the effect you describe...the other way round results in the magdyno contacting the rear of the timing chest.

How close are the countersunk screw holes underneath the plate to the face that slots between the engine plates ? A photo would help.

This should help ! Courtesy of Alex from the Singles Facebook group 

Just to clarify the captions on Dan's post....On the left are for the the 1948 pattern engine. Centre (given as wartime16H) is actually for all OHV / SV 1936 - 37 and WD16H...and those on the right are for the 1938 enclosed valve engines.

Yep, been there, done that -  As Dan says, we all have !

For a 1937 engine, you require the plate where the mounting face bisects the screw countersinks. I haven't had to do it, but it would seem logical that the rear face could be milled and a spacer used on the front edge...but it may make the platform more difficult to keep tight and they can be a little problematical if there is any wear on the engine plates.

This photograph shows to variations of the early type alongside a 1938 pattern. Apologies for the poor quality phone picture.