A,
Think very carefully before trying to make your own Bio diesel. Although it is a relatively easy process, it is fraught with danger. You will be using two very toxic substances in the transesterification process, i.e. Methanol and Lye. I used to make Bio diesel until my company sent me on a Methanol handling course. I won't go near the stuff now. Instead of me trying to explain why it's both dangerous and highly poisonous, I recommend you do a little research on-line. The combination of Methanol and Lye results in an even more toxic substance.
I switched to using WVO, which is simply veg. oil which has been filtered & settled. I have to either blend the WVO or pre-heat it before it reaches the injector pump, to reduce the viscosity. I actually do both. I thin it with petrol, then heat it with a home-made heat exchanger.
If you buy Bio diesel from someone else, you need to be very careful that person knows what they are doing. Poorly made Bio diesel can wreak havoc with your engine. Some car manufacturers warn not to use Bio diesel in their cars, as it can wreck certain seals in the fuel system. It is a very powerful solvent.
I seriously recommend that you use WVO rather than Bio diesel, and do plenty of research on-line, if you haven't already done so.
Good luck, Stewart