Here is a sure fire way to fix the emmissions problem. Some of my fellow R/C airplane associates use the Cohlman fuel mixed with castor oil in their tanks. They use this mix in their weed eaters too.
The end results are no smoke and a very clean burn to boot.
So I reccommend the white lightning fuel and castor oil mixture as your cure. Good luck at the state testing shops for you all in CA.

Maximo