There are different kind of flames: traditional ,wall-of-flames,realistic and ghost ones.
Be it on bykes, cars, helmets or other cutom objects, the trend is hot and it make sense to explain to you all.
I am preparing online tutorials so be patient...I am only human :-)
Meanwhile, to start with, here is the best book on the topic.
Here is it
"What a great book! The examples shown are awesome and inspiring. All you need to make the different flame styles is explained in detail. The book is layed out beautifully, pictures are large, in color and of very high quality."
"The best instructional book I have ever read regarding Flame design [and ]inspiration ...."
"great photos and good instructions...
I would recommend this book to any one considering a flame job. "
"Clear explanations about design, taping and masking, painting techniques and tips, and a lot of close-up pictures showing exactly what's going on."