Thanks everyone for the information about adding smoke to my Spectrum K-4. I will back off for a while on this. I am going to check into the Rapido's smoke flluid, since it may not leave a oily residue and will clean the track. Again thanks for all the information and the help. Ranger

I have a spectrum K4 engine and I am wanting to add a smoke unit to the smokestack. Is this possable and how would I do this? I would like to see this smoke as it rolls around the track. Hope someone can help me.