I have been reading this thread for about two weeks. After the cdi quit on my TT 90 that had been converted to gas. I changed to the OS "F" type plug and gave it a try. On regular gas oil mix. It runs good on top end, but after idealing for a few seconds it starts to 4 cycle and is spitting out a lot of unburned fuel. Had to quit it was getting dark, and then the weather turned cold. When it worms up I plan on leaning out the low side and trying it again. Transition was very rough. Can I mix glow fuel with the gas oil mixture? Anybody got a good CDI for the 1/4 inch plug?