Free auxiliary tank!

The 999 injectors are the shower type, so the injectors, TBs, TB linkage, and idle screw are all completely encased in the airbox. So even simple things like setting the idle require running the bike with the airbox open, a major pain in the ass because you can't just hang an auxiliary tank to do tuning.


The stock tank can be used like an auxiliary tank for tuning, just strap it backwards to the subframe. Support it with a 2x4 so it doesn't rest on the fuel lines & fuel pump harness. In this orientation, the send & return orifices on the pump will be reversed with respect to the fuel lines. However, for tuning, it can and will run fine in this configuration. Both lines meet at the junction just before entering the airbox. This junction is non-directional, so it doesn't know which side is pressurized and which is the return. Essentially the two lines form a loop between the send and return; at one point in that loop it branches off at the junction to go to the injectors.

I used this configuration to run some Seafoam through the TBs (sending billowing clouds of white smoke into the neighborhood), and subsequently reset the TPS & idle.