Strange Ignition problem

Hi, I have a VB1T 150 super, I changed the sparkplug last week (same mode of NGK), it worked perfectly for 3 days and then it begun to back fire, and impossible to start it again:

I cleaned  the sparkplug (quite oily and black) but it sparks, then it look it very dry, she started again making a lot of blue white color then stop and backfire. when I remove the spark plug again, it still very clean even dry. I cleaned the Carb, but no improvement.

If I have sparks then it is not an electricity pb.

Thks for your advises


I think that this problem is for your ignition timming, but also, you could look at your crank, maybe it can be damaged!

First thing to check is your ignition timing [;)]

HI Hamer

Thks I have done it a month ago but will do again, I am thinking to install the following kit, any advice?


DO you know if SIP have this one my vespa flywheel has a circlip so I can't install a PX kit.