It can be quite normal
Make sure the Throttle is open when you try it - If the throttle is closed, It won allow any air to enter the cylinder to be compressed.

Off Topic but another tip for you if you aren't aware of it:
Is it a new engine? and are you familiar with the 100?
If it is new - you may find it vibrates a lot at low RPM's - Some of the 100's do that and some don't - it's caused by an extremely rich low speed needle setting - Once you get it broken in and lean out the low speed - they become smooth runners (One of mine took 4 full turns of the LS needle to get it to the correct place)