Hi... I get some back fire on occasion when I let off the gas (which is rare! <grin>) and I do believe my timing is off a little. Decided to check the timing to day and removed the Timing Inspection Hole Plug. Now somewhere I seem to remember reading I needed a site glass or some such thing to put in the hole in lieu of the Timing Inspection Hole Plug but couldn't remember for sure... When I started the scooter I knew my memory had been correct! This major spitting noise was coming out of that hole... so I shut her down and put the plug back in. Now.. I live in China... don't know anywhere I can go to find this said "sight glass" or whatever it is... leading me to two questions... 1.) Will it hurt if I go ahead and see if I can check the timing without the glass? 2.) Does anyone know where I can buy the glass? Cheers and regards!