Fuel supply problem??? (sick Valkyrie)

[sidecarrick]

 Hi, fellas. I've removed the gastank to put new throttle cables on my y2k tourer because I put deuce risers on it and the throttle wouldn't return on it's own. Took off this morning to go to London to visit our chapter president Adrian (Chrome) and after about 15 miles at highway speed the bike began to sputter and acted like it was running out of gas. Once I stopped and let it sit for 5 minutes it was fine for another few miles and the above performance was repeated ad nauseum until we got back to Windsor. At city speeds, the bike ran well, but at highway speeds it sputtered. I pulled the tank half way off (not enought tools on the road) to see if a gas line or vent line was kinked and discovered a T about a foot down the vent line (the last fitting at the back of the tank) that had nothing attached. I'm going out to the bike now to pull the tank off. Anything I should be looking for and what does that T connect to?? Thanks for any and all responses. 

[Ricky-D]

That "T" is there to break the siphon, nothing attaches to the open end.

***

[wild6]

Do a search for 'petcock diaphragm' and you should have enough to read for a long time.....

[hubcapsc]

It could be your petcock, but it's probably got something to do with
taking the tank off...

There's three lines that more or less go to the tank... the big gas line, the vacuum
line down to one of carb intakes (#6), and the vent tube out the back.

I bet your problem is something easy to fix, maybe something's up with one
of the three lines... probably not the big gas line, it is probably hard to mess
that up without a bunch of raw gas and fire 

-Mike

[gordonv]

You rule out the vent tub by opening the gas tank cap. No extra key? Stick something under the cap to break the seal when you close the cap.

One of the easiest things to look for first, before trying some of the other possible problems. Vacuum leak, peakcock problems, etc.

[sidecarrick]

Tried running the bike at speed with the gascap open and still no change- sounded like it was running out of gas. Took the gastank off the bike and took the vacuum hose on carb 6 off and blew through it with the end capped- no leak. Took the petcock apart to check the diaphram- no tears or holes (looked under magnification). While the petcock was off, I blew throught the fitting where it connects to the tank to see if the screen was plugged and judging by the amount of gas the vent spout at the back of the tank spewed into my face and ear, it's not plugged either (seriously, open the gascap before attempting this ). Kind of at a loss as to what may be causing the problem. Please keep the ideas coming. Thanks

[John Schmidt]

And remember this....the next time you feel the need to replace the throttle cables, DON'T pull the tank. It absolutely is not necessary, I've done it many times. Frustrating the first couple times you try it, but not nearly as troublesome as pulling/replacing the tank.

[hubcapsc]

Tried running the bike at speed with the gascap open and still no change- sounded like it was running out of gas. Took the gastank off the bike and took the vacuum hose on carb 6 off and blew through it with the end capped- no leak. Took the petcock apart to check the diaphram- no tears or holes (looked under magnification). While the petcock was off, I blew throught the fitting where it connects to the tank to see if the screen was plugged and judging by the amount of gas the vent spout at the back of the tank spewed into my face and ear, it's not plugged either (seriously, open the gascap before attempting this ). Kind of at a loss as to what may be causing the problem. Please keep the ideas coming. Thanks

This shoptalk link shows how to do a vacuum test on the petcock, while the petcock is off the tank...

http://www.valkyrieriders.com/shoptalk/petcock.htm

It is easy, and telling...

-Mike

[Daniel Meyer]

You've ruled out the vent line, what's left is the petcock...go the vacuum check of it and check the vacuum line to it for kinks/etc.

[sidecarrick]

Well. I did what I thought I should do and what everyone else told me to do and I just came back from a 100km ride. The bike runs perfectly!! Not exactly sure what was wrong or really what I did to fix it, but after I CAREFULLY re-assembled everything things are good once more. Thanks to all for the advice- I probably couldn't have done it alone