Hi, my name is nick, i m rebuilding my RD04 , 1990 , africa twin. i want to build a carbon fiber fuel tank using the original as model , maybe increasing fuel capacity . it is a large tank, 24l , so i m thinking about reinforcements , wave breakers.. I appreciate any advice regarding methods of construction , moulds, bonding external with 'tunnel' ...inserting threaded bushes for fuel taps.. etc.  I have a two stage vacuum pump Robinair , 71 / min, is it any good? Thanks 

Since nobody has replied so far I'll bite.

Vacuum pump is perfect (if it is in working condition).

Here's a link to get you started:

http://www.bayarearidersforum.com/forums/showthread.php?threadid=145975

I have a few issues with this built, (like don't know why he didn't use twill for the outer layer...), but then again he built a tank and I didn't.

Good luck with the project... 

thanks, a split mould was in my mind too,, for the out part. the ' tunnel' is not so visible  but is full of holes ; africa tank have two fuel taps and indicators. my next step will be to talk to the guys on the staff to decide a list of materials and tools. 

Some things to consider:
Is a homemade tank street-legal? Todays fuel contain ethanol, which attacks many epoxy resins. Tank will need some kevlar if you drop the bike.

Making a tank is not too hard once you have figured out the moulding of it..
Legalities seem to be a none issue most places but it is worth checking, if you plan to sell them. 
Inserts for fuel taps and filler caps are not hard or expensive to source and I use normal woodworking T Nuts. 
Materials? Carbon for the inner and outer layers I would not use Kevlar personally I would use Diolen as it is a better material for abrasion compared to the more ballistic resistant Kevlar. Resin to seal against ethanol needs to be a Phenol Novolac resin. You can use it to make the tank fully or as a sealant. I do the latter as I make mine from Pre-preg carbon. 

Here are some photos.. I have made a tank only this week but had to modify one from my full monocoque seat/tank unit. I cut it down roughly to allow me to make the tank outer and trim it down and tidy up edges when I install the tank base.