For those who want to make a fuel system test of an R1150RT to check its condition, here's a straightforward method based on the fuel pump spec of delivering 110 liters/hour at 43 psi). Other systems may have different numbers.
Put a fuel pressure gauge in series with the high pressure line.
Take the return line and route it through a hose with a QD into a fuel container. Take all appropriate safety precaustions and have a proper fire extinguisher on hand. Do this outside if possible.
Start the motor and let it idle for two minutes exactly, then shut off the engine. You should have just under 1 gallon in the container. The fuel pressure during idle should read 43 PSI plus or minus 4 PSI.
Feel free to check the numbers, I'll be testing my system later this week or next.