WOT stumble

[RDKLL]

OK Valk gurus.......
We completed our move to Philly and I wanted to ride.....the bike would not start
1. Replaced the 35 low speed jets with new 38's
2. Replaced vacuum lines and vacuum plugs
3. New air cleaner
I got so exciited about getting it apart I neglected even a cursory look at the high speed jets.....we are thinking there may be partial clogs or something that would explain the ability to run 80mph or whatever steady until I twis the wick.......
Since the jets.....was suggested that the petcock may need to be rebuilt, I had a new, never used one that I put in (further suggested that it may be old enough to have the seal dry up as well, rebuild kit ordered)
Changed the oil (not related to the problem  )

Now it starts great and it has a high rpm > appx 3-3.5K rpm stumble...feels like its running out of gas
It will run 70-80 or whatever speed with steady throttle
But when I twist the throttle for more it gets the stumble like its not getting gas
I have run a bunch of Techron thru for about 100 miles and its still doing it.

I guess if I was going to state the problem in one short sentence......
It would be the title of this thread....A stumble at WOT.

Rick suggested that I check the airbox to carb tubes and they look good.
He then suggested that I post here before I tear into it again.

As always, Thanks in Advance

[YoungPUP]

grab your inspection mirror and a good light. its REALLY easy to roll the back edge of the tubes under when reattaching them to the carbs.  ( or so I hear.. )   Did you change your fuel line from the tank to the carbs when you did the work? if so check to make sure that its not too long. I did this in an attempt to make it easier to lift the tank to disconnect the lines for removal, and She was not a fan of that Idea at all. Cut the extra inch that I had added, and everything went back to happiness.  I may be speaking out my excrement orifice but those are the few problems that Ive learned my way through that had the same affect that you're dealing with

[Chrisj CMA]

If you check all the connections,vacuum lines and such and it still starves for gas at RPM it could be the petcock.  At its best the Honda petcock JUST keeps up with high rpm demand.  Any degredation in fuel output and the engine will empty the float bowls faster than they can be filled by that OEM valve

[Blackduck]

Is the air box lid standard with the foam pad in it? Just missing that pad can cause it to be too lean at speed.
Cheers Steve

[RDKLL]

Well I got a couple of very good ideas last night in chat:

Today I will be pulling a vacuum and making sure that I have fuel flow

Hold the vacuum and be sure of continued fuel flow

Finally, someting I should have thought about after living in Alabama......mud dauber, hornets, wasps or whatever.....they would build a nest anywhere......check the exhaust for blockage.

I went to Harbor Freight and bought an inspection mirror and got a free 9 led flashlight....the rubber airbox tube to carb all looked good

[fordmano]

With that thought about Mud dobbers, you might want to verify your tank vent is open and free flowing. A blocked up tank vent can cause a vacuum on the tank and slow or stop teh fuel flow through the petcock. Try running with the gas cap popped open a little bit.

[Ricky-D]

Even with all that has been posted I would suggest considering that the battery might be performing poorly or the alternator might be failing.

The Valkyrie requires a lot of electrical power when powering in the high rpm range.

Any kind of electrical bottleneck will surely show up under those conditions.

***

[RDKLL]

Well after doing everything anybody suggested.....and after running what seems like gallons of techron plus......I will be tearing the carb bank back out....and do the high speed jets like I should have done before, just got so excited about the low speeds, forgot to look at the high speeds....should go much faster than the last time...and by the time I do it on the other Valkyrie....almost be able to do it in my sleep 

[DFragn]

RDKill,

You might want to pull your carb covers and inspect the diaphragms for small tears or holes with a bright light. Be gentle they're delicate as are the cover screws.

That's what I'd do before I'd pulled the carb bank again.