Engine change M to H

[old servi]

I have a few questions on engines. Could you tell me what year is a M20655 engine.
Would the M engine work well in an H Servi 40's model.
If using the M engine, what happens to the compression release system with no
place to hook up the twist cable on the M engine.

Any Help appreciated.

[Ricks]

Good question, and I don't have a answer, but I wonder if the belt path from the motor to the pulley is the same on both.  If not, this could be an issue. I also know that the M models do not have a belt guide, as do the shifter models.  This could also be a problem, as the belt goes slack it could pop off.  On the M, the belt is tensioned to the clutch by a spring.

As for the compression release, just don't use it, and add a switch to ground out the spark, as is done on the late models.

[Mike Sal]

Your M motor is a 1956 model. (do you have the bike it came from?  if so, send me the serial number).  As rick mentioned, you might need to add a belt guard to reduce the chance of the belt coming off if using it on a 40's model.  Does your bike have a foot shifter?
Mike Sal

[old servi]

The Frame is a 40's model. Is there a serial number on the frame to get the year status. It has everything 40's except the engine that came with it and not installed. Has a regular 40's clutch and foot pedal for clutch.
I also have a automatic clutch that came with the engine that needs bearings and putting back together. I have no diagram for the automatic clutch to see how it goes back and how it would hook up if I used it instead of the standard 40's clutch.
The carb on the M engine is different from my carb on the 46 I have also.
More than likely if I can just install the engine, I would use the 40's clutch anyway. The engine also does not have a Wico mag.
Thanks

[pd]

The M manual has a breakdown for the automatic transmission .

http://www.simplexservi-cycle.com/index.php?topic=430.0