Fuel Reserve Problems

[sheeres]

Have been having a wierd problem as of late.
On a trip to the UP of Michigan (great gas mileage!) near the end of the trip, when switching over to reserve. First 1/2 mile the bike ran fine, then acted like it was not getting gas, putterred off to the side of the road, sat for 5 minutes, fired it up and was off for another 30 miles and a fill up.
Happened again, only this time I ran for around 5 miles on reserve alternanting between running fine and sputtering. Again, sat for 5 minutes and it took off for another 20 miles to the next fill up.
In trying to pin point the problem, on the next tank of gas, I left it on reserve...and had no problem (I ran it well past when I would have switched to reserve).
Next tank I switched it over when I got home and the mileage was where it should be close to hitting reserve...next morning it fired and ran fine.
Last tank I ran it 'normal', switched over to reserve, it ran fine...until I put only 1 gallon in it (I was going to be working on the bike and wanted the gas tank as close to empty as possible), left it on reserve, ran it for 8-10 miles and had the problem again...waited 5 minutes...nothing, switched it to PRIME started and ran fine the rest of the way home.
I now have the bike up for other repairs and would like to fix this issue..if I knew what the issue was.
Anyone have this problem or know of any solutions??

[xs650mike]

I haven't had this problem with my XS11 as yet but I've had it on many other bikes in the past. It's usually caused by rust or other crud in the gas tank. The stuff settles to the bottom and since on the normal petcock setting the fuel is picked up some distance from the bottom everything runs normal. When you switch to reserve you're picking up from the bottom of the tank where the crud is and the stuff clogs the filter screen causing fuel starvation. Then you fill up the tank and the fuel flowing in kind of cleans off the screen and things seem normal for awhile especially if you switch the petcock back to normal. Sounds like you're in for a cleaning of your petcocks and screens and a flushing out of your tank. It would also be a good idea to electrolytically clean the rust from your tank and then coat it with one of the tank coatings that are available (Yamaha sells a good one) so that the problem doesn't recur.

[sheeres]

I had thought of this, but ruled it out because the bike runs well after it sets for a short time. If it were gunk in the tank, the problem would come back once I got the bike back on the road 'shaking things up' in normal driving.

[xs650mike]

I'm still thinking that your problem lies where I said. The only other thing I can think of is that the electronic iggy has some sort of thermal glitch after it warms up a bit. I had a problem like that on one of my 650s and as soon as I installed another iggy from the junkyard the problem disappeared. This is a really rare problem, usually an iggy will work or it won't. What say the XS gurus out there?

[sheeres]

Think I figured out the problem.

The octypus has been replaced on this bike with a fuel shut off valve...that is positioned below the carb fuel bowl.

Unless the petcocks are switched over quickly, air probably gets into the system and it looses it's prime. During the time the bike just sits gives the system it's prime back.

Another biker and I were hashing over the problem when the light came on.

[xs650mike]

Congrats!