Maybe cutting out?

[Farther]

As a new owner I have started to notice what seems to be a slight hesitation or subtle cutting out when cruising at a steady RPM.  This happens at all RPMs but only when holding at a steady speed.  The bike accelerates very strongly without any noticible cutting out.  No problem in starting or idleing.  No change in the tach or speedo with this hesitation.  Any advise is appreciated. 

[lee]

Pull the vacuum line off number 6. Pull vacuum on line with mity vac.
If vacuum leaks off in 2-3-4 seconds its bad vacuum dia. in petcock.

[Kingbee]

When cruising at speeds less than 3,000 RPM, you're probably running on the pilot (idle) jets, which may be partially clogged. (happens a lot)   Get yourself some Techron concentrate, or Seafoam, and put at least a quadruple dose in the tank and go riding normally.  If the first tank full doesn't clear it up, try again.  If no success, come back to this post and let us know.

[Farther]

I am currently on my third can of Seafoam in the last 500 miles.  Today I put one can in a full tank of gas and rode it 100 miles varying the speed from 45-65 mph.  Still doing it.  I will see about using a two can dose and getting a vacuum tool and try testing the petcock.  Could it be something in the spark or other part of the ignition?

[R J]

What part of the country do you live in?

What grades of gas do you have available to you, along with the octane,

[98valk]

I am currently on my third can of Seafoam in the last 500 miles.  Today I put one can in a full tank of gas and rode it 100 miles varying the speed from 45-65 mph.  Still doing it.  I will see about using a two can dose and getting a vacuum tool and try testing the petcock.  Could it be something in the spark or other part of the ignition?

your paying top dollar for alcohol which already is in your fuel.
http://www.thehulltruth.com/boating-forum/203184-seafoam-contains-10-20-isopropyl-alcohol-ipa.html

Seafoam ingredients:

Isopropyl Alcohol (rubbing alcohol), pale oil, and naptha.

there are much better products to use than SF out there.

www.bobistheoilguy.com

[Farther]

What part of the country do you live in?  What grades of gas do you have available to you, along with the octane,

  I live on the CA/OR border at about 2300 feet elevation, about 30 miles from Mt. Shasta.  I run Chevron or Texico 87 octane gas usually. 

[Farther]

After running a can of SeaFoam through 1/2 tank it is still doing whatever it is.  I even got 39 mpg on my 100 mile loop while keeping the speed between 45-65.  So I filled up with Texico and dumped in a bottle of Techron.  The MightyVac is on order.  I presume that I locate the vac line on the carb, disconnect that and leave the other end attached to the petcock?  How do I go about locating the vac line to #6 carb?

[FLAVALK]

I had a similar problem with a previous Valk that I owned. Turned out to be a lot of trash in the tank...rust, sand, dirt kind of trash. Drained & cleaned the tank and petcock screen really well and the miss at speed went away.

[Zep]

My 01 started "missing" in a similar manner.  Turned out to be an air screw that wouldnt adjust.  Now it rins better than ever.

Zep

[Mr.BubblesVRCCDS0008]

Just a thought check all clamps on the airbox to carb, carb to rubber hose and hose to intake manifold.  These seem to loosen with time and you maybe sucking air.

[Farther]

My Mityvac came in the mail yesterday and it tested good.  So this morning I went out and disconnected the vacuum hose from the #6 carb and attached the Mityvac to that hose line.  The Mityvac could not establish a vacuum.  Now I did have the petcock in the off position as I thought that when (if?) I established a vacuum the fuel would then flow from the tank into the cylinders leading to hydrolock.  It seems that the petcock need to be rebuilt which will happen when the UPS person makes the delivery from HDL.  MY QUESTION IS: Did I use the correct test procedure with the petcock in the off postion?  Anybody please advise.

[Farther]

My thinking is that the petcock needs rebuilt.  This problem seemed to state shortly after purchasing the bike and the start of using SeaFoam.  I wonder if the SeaFoam dislodged enough crap in the tank to obstruct the filter screen on the petcock.  Well, I will find out shortly after I get the rebuild kit for the petcock and screen.

[Kingbee]

You tested correctly.  You should be able to establish a vacuum with the petcock in any position.

I disabled the vacuum portion of my petcock and installed the Dan-Marc electric fuel valve.  Fuel only flows when the ignition is on & is much cheaper than the pingle.This also prevents fuel leaking down the vacuum line to cylinder 6.  Another plus is, after draining the carbs, just turn the key on for 30 seconds to fill the bowls - Eliminates all that cranking & she starts right up.

[Ricky-D]

I am currently on my third can of Seafoam in the last 500 miles.  Today I put one can in a full tank of gas and rode it 100 miles varying the speed from 45-65 mph.  Still doing it.  I will see about using a two can dose and getting a vacuum tool and try testing the petcock.  Could it be something in the spark or other part of the ignition?

Why keep trying the same stuff and expect different results.

Try that Tech stuff for a change.

And cutting out is not really what's happening is it? 

We all know what cutting out is, at least we should and you Valkyrie is not cutting out. That would be an electrical ignition problem.

Might be , most probably will be a synchronization problem if a couple of cans of Seafoam haven't cured it.

I'd suggest doing a complete de-smog. Stops any vacuum related issues in their tracks.

***

[Farther]

Why keep trying the same stuff and expect different results.  Try that Tech stuff for a change.

  Apparently I am not as smart as you.  What is the "Tech stuff" you are referring to?

[Kingbee]

I believe he's referring to Techron Concentrate - a better fuel system cleaner than Seafoam, IMHO.

[Farther]

Well, I have run two bottle of Techron through the bike too with no change.  The closest dealer is 60 miles away but I have an appointment with a better dealer 100 miles away for a tire change.  Then someone can physically look at the bike.  In the mean time my new petcock rebuild kit should be here.  Thanks for the suggestions.

[Ricky-D]

My Mityvac came in the mail yesterday and it tested good.  So this morning I went out and disconnected the vacuum hose from the #6 carb and attached the Mityvac to that hose line.  The Mityvac could not establish a vacuum.  Now I did have the petcock in the off position as I thought that when (if?) I established a vacuum the fuel would then flow from the tank into the cylinders leading to hydrolock.  It seems that the petcock need to be rebuilt which will happen when the UPS person makes the delivery from HDL.  MY QUESTION IS: Did I use the correct test procedure with the petcock in the off postion?  Anybody please advise.

It doesn't matter which position the petcock is in  (On-Res-Off) , it is a closed system and should allow you to get a vacuum regardless.

[Daniel Meyer]

Yes, your petcock needs rebuilt.