I have a 06 650i bf wich is completely stock that I would like to put a shutoff on. I have had it hydro lock 2 times after having had it trailered. I think for long hauls the floats bounce letting fuel by filling the jugs. What size shutoff do I need and where is the best place to put it so I can reach it easily. Thanks in advance.

Sodak

 

Before installing the fuel shut off, do this experiment:
When loading up your quad onto the trailer next time, change the orientation of the quad on the trailer.
For example:
1). If you normally head-in, then back-in.
2). If you back-in, then head-in.
3). If you load it up sideway (transversed), then load up longitidunal (either head-in or back-in).
I've seen the same problem on other quads, this worked for me.

 

Check to see if your fuel tank vent is clogged. Fuel may be forced by your float needle if pressure is not allowed to vent.