Bike dies after an ~hour of operation.(SOLVED fuel pump)

[tbyte]

It has happened several times. I should mention this issue began after I had a low speed wipe out. After running forty five minutes or so it loses power and dies when I open throttle but will run at idle (for a while).  I have made it home in first.  After letting bike sit for an hour it will start and run fine.   The float bowls are full and the gas is clear.  I pulled and inspected the vacuum line from fuel pump to manifold and it seemed sound.  I was about to rebuild fuel pump but if the floats are full then would it even be a fueling issue?  
-Immediately prior to losing power she was racing in neutral at stop lights.  I was engaging the clutch to slow engine which helped but it still seemed faster than usual.
-Manual petcock
I am looking for suggestions.  Thanks in advance.
Jerry

[greenmonster]

When these symptoms happened to me, it was fuel pump failure, semicollapsed diaphragm.

[koko64]

Were the float bowls actually full or showing some fuel content? It does sound fuel supply related since it will idle. Is the weather quite warm? Fuel strangulation? Maybe a collapsing fuel line once hot? Greenmonster raises the pump issue which can be tested by bypassing it with a full tank. Range lasts until the fuel level drops lower than the carb inlet height.
Normally ignition related issues result in a total engine cut out of one or both cylinders depending on which component has failed. The faulty component fails when it reaches a certain temp after riding awhile.
I'm still thinking about the racing idle before it cuts out. Strangely it can be a sign just before the float bowls empty.
Also, no fuel coming out of the overflow hoses? Crashes can shake up float bowl components and also stir up fuel tank sediment that can choke pumps and taps.

Write down the list and go through checking them all starting with the rubber vent nipple under the fuel cap (remove it) then looking for kinked fuel hoses, checking tap flow and then bypassing the pump. A hose might only kink once the tank is lowered or get squashed against the head and collapse when hot.

[tbyte]

When you say semi collapsed diaphragm you mean the carburetor diaphragm?

I had drained the floats just enough to see if any water in gas maybe half an inch in jar.  I shut it before they emptied fully.
The racing(better described as unusually slow to idle) happened yesterday after getting off highway.

I will go through the checklist thanks, I just thought if there was (any)gas in the floats when it stalled it means the fuel pump is working.

[Howie]

Also, if you still have the factory vacuum fuel cut off, for diagnostic purposes, bypass...better yet, replace with a manual petcock.  The bowls don't need to run dry, just low.

Greenmonster is referring to the diaphragm in the fuel pump.

[koko64]

Manual fuel tap. Worth checking flow after the lowside in case something dislodged and is half blocking it.
Had an old 750 Bonneville T140 that starved for fuel in left handers. Checked the tank and found a dope stash left there from a previous owner. The rubber bag had melted so I guess it was there since the '70s.

[greenmonster]

" Checked the tank and found a dope stash left there from a previous owner."
 

Meant what I wrote, fuel pump diaphragm.

[Howie]

Manual fuel tap. Worth checking flow after the lowside in case something dislodged and is half blocking it.
Had an old 750 Bonneville T140 that starved for fuel in left handers. Checked the tank and found a dope stash left there from a previous owner. The rubber bag had melted so I guess it was there since the '70s.

Excellent diagnosis

[koko64]

" Checked the tank and found a dope stash left there from a previous owner."
 

Meant what I wrote, fuel pump diaphragm.

Yes I think it could be bypassed to to test it

[koko64]

Excellent diagnosis

When I found the T140, she was a purple chopper with ape hangers, extended forks and spike fork caps. Two years later she was stock. Learned alot from that bike.

[tbyte]

It was the fuel pump, thanks.

[koko64]