I thought that I should share I problem that I recently had with my 151cc TGB scooter.
I have driven my scooter for over 3000 miles without any problem but last week the engine suddenly died while I was cruising along at 40mph.
The starter could still turn the engine over but the engine did not start anymore. After about 20 mins I tried again and the engine started immediately. However, after riding the bike for another mile or so the same problem:
engine suddenly died.
Finally at home I discovered the reason:
There is a breather hose going from the cylinder head cover to an airbox. The airbox is connected to the engine intake and there is another transparent hose from the airbox going down which is terminated with a plug.
Obviously the purpose of the airbox is to ventilate the engine valve compartment and to feed any oil vapor back into the intake so that it can be burned in the engine. But depending on the weather conditions there is also condense water coming from the valve compartment into the airbox and is collected by a sponge in the airbox. Water dripping down from the sponge is collected in the transparent hose but it can't go anywhere from there because there is a plug at the end of the hose. In my case the entire hose was full of water and water started to accumulate in the airbox and got sucked into the intake. And this caused the engine to die.
As far as I have seen, there isn't anything written anywhere in either the TGB owner manual or service manual that this transparent hose needs to be opened from time to time to empty it.
You should definitely empty this hose from time to time.
Please don't forget to put the plug back into the end of the hose. Otherwise ventilation of the valve compartment will not work properly!
