Can someone explain this fuel shutoff please?

The fuel shutoff on my maxim is like nothing i've ever seen before. there is an on, a reserve and a prime position. What position should the lever be in when starting the bike, running the bike, and storing the bike? Is there a way to actually shut the fuel off when the bike is not in use?

 

Only sorta kinda.

The petcock is vacuum operated. "ON" and "RES" should only allow fuel to flow when they receive a vacuum pulse from the small hose that connects to the intake manifold (#2 on a 550.) "PRI" allows fuel flow, regardless of vacuum signal.

If the petcock is operating correctly, when it's in ON or RES, it should really be off unless the motor is running (and it's getting a vacuum signal.)

If it's not operating correctly, it should be rebuilt or replaced: http://xjbikes.com/Forums/viewtopic/t=25058.html

If everything is working correctly, you leave it ON all the time, use RES when needed, and PRI only to top off the bowls after it's been sitting for a week or so, or to run it while doing a vacuum sync.

 

ON, ON, and ON...unless you run out of fuel, then it's reserve.

It is a vacuum operated petcock. In the RES and ON positions, while the motor is turning, a vacuum is created to let fuel flow.

In the PRI position, fuel flows all the time. PRI is mainly for filling the float bowls after they have been drained for a cleaning or winter storage.

You can test the petcock by pulling the fuel line while it is in RES or ON position. If fuel doesn't flow (you will get a few drips regardless) from the output, then it works. You should be able to turn in to PRI and have fuel start flowing.

 

Phew, that makes me feel better, now i don't have to worry so much about gas leaking all over my garage floor. I appreciate all your help

 

That's not necessarily true. Malfunctions of 30 year old vacuum petcocks aren't rare.

On a nice day roll it outside and disconnect the fuel line. Make sure nothing comes out in either "ON" or "RES". If it even drips rebuild it.

 

Good advice. "OFF" is just a function, and is dependent upon the petcock functioning correctly. Drippy petcock syndrome is common; again, look here: http://xjbikes.com/Forums/viewtopic/t=25058.html to help understand why, and how to cure it.