JRM83
XS400 Member
Hello all. I just picked up my very first bike. A gorgeous 81 xs400 special II. Now I've been getting acquainted With pre fuel injection technology. I've been stumped on the petcock. I understand it's operation in ON RES and PRI settings. EXCEPT I don't understand how it can fill the float bowls at full throttle in ON. It seem as soon as the throttle opens all the way the ball valve in the petcock will close. This will cause the float bowls to quickly drain. And since float level is so important for the proper operation how does it compensate. Especially when driving up a steep hill. Or on a top speed run. Or theoretically when "towing".