Valkyrie Losing Power While Riding Or Towing A Trailer

[Bert AKA,Valkaholic]

Has Anyone Had Their Valkyrie Lose Power,(like Water In The Gas),Or ( Coil Failure)? One Of My Valkyries Started Losing Power While Cruising At Hi-way Speeds,(55-70)Mph, And it Comes And Goes Intermittingly. I Rebuilt The Carbs Last Year And It Is Ridden Regularly. It Has 94000, Miles On It. It Acts Like One Of The Coils Are Failing, Especially Noticeable While Pulling A Trailer. It Does Not Do It Constantly, Just From Time To Time. It Acts Like It Is Dropping Two Cylinders And Then It Will Clear Up And Run Like It Should. It Usually Runs Fine Until I Pull The Trailer Or Put It Under A Load. Without The Trailer It Has Acted Up ,But Not As Often And Is Not As Noticeable. I Am Just Wondering If The Control Module May Cause This! I Have Some New Coils And Plug Wires Coming And Will Eliminate That Part Of The Equation But I Am Not Wanting To Just Throw Parts At It .If Anyone Has Had This Problem Please Let Me Know, Any Help Would Be Appreciated.
Thanks, Bert.

[Gryphon Rider]

Possibly a loss of vacuum at the fuel petcock?

http://www.valkyrieforum.com/bbs/index.php/topic,37577.0.html

[Black Dog]

Sounds like you've got more than one Valk...  Swap out the ECM, from one of 'em that seems to be running well, for a week or so, and see if that fixes the issue.

I had a bad ECM, but it was running rough right from when you started it up.  Couple of cold pipes, and I also thought I had a bad coil.  Got an Interstate ICM, from Big Mike, and have never looked back.

Black Dog

[signart]

Sounds like starving for fuel.

[JC]

What Gryphon said......

I'm also betting that you don't have the problem until the tank is at least half empty.

You mention that you rebuilt the carbs last year, I'd check to make sure the fuel line hasn't got an obstruction or small kink and is routed downhill from the petcock to the carbs. Did you replace the fuel line also? A fuel line that is slightly too long can have just enough of a bend to create this issue.  Don't ask how I know.........

[97Valk_CT_Euless]

I had a bad petcock diaphragm give me trouble.  Was leaking but only lost fuel flow under heavy load (poor vacuum conditions).  Pulled it apart, had pulled out of it's groove in the cover.  Put it back, it seemedd fine, but pulled out again soon.  I replaced the cover set and that fixed it, but then I added a check valve with a tiny hole in it to the petcock vacuum to reduce the pulsation.  Jusry's still out but 4 months and no problems, ridden almost every day.

[Firefighter]

My experience, usually coils or spark is a jerky feeling and fuel is slow and smooth loss of power. Kind of difficult to diagnose if its once in a while or at hiway speed. Let us know. Firefighter

[Bert AKA,Valkaholic]

Thanks For The Input, I Also Thought That It Could Be The Fuel Petcock But It Only Happens At Cruising Speed And Under A Load, Not Continuously. I Can Ride It For Fifty or Sixty Miles And Not Have A Problem ,Then It Will Act Like Its Running Out Of Fuel But Never Has Quit Running Or Left Me Stranded, Then It Will Clear Up And Run Fine. I Do Have More Than One And I Will Try Changing The ECM First Then The Petcock Second. If It Continues Then I Will Change The Coils. I Will Do This Sometime This Weekend And Will Post My Findings.

[Hook#3287]

Hey Bert;

Any chance you got a inline fuel filter on that one?  That happens on the one I added a filter too.  It's coming off this winter.

Bill

[hal47]

I would try a new set of plugs if they have been in there a while, plug usually break down under a load when they are geting bad.

[longrider]

Bert

I had similar symptoms with my first valk.  it was the petcock..when the diaphram gets a small tear in it it it will not fully open under load.  hope you are healing well

Warren

[samoanrich]

Bert, I have a ecm if you want to borrow it, let me know.

[Bert AKA,Valkaholic]

Hey Bert;

Any chance you got a inline fuel filter on that one?  That happens on the one I added a filter too.  It's coming off this winter.

Bill

Hi Bill , I Do Not Have An In-line Filter On It And No Kinks In The Fuel Line.

[Bert AKA,Valkaholic]

I would try a new set of plugs if they have been in there a while, plug usually break down under a load when they are geting bad.

I Will Change The Plugs To See If That Is The Problem.

[Bert AKA,Valkaholic]

Bert, I have a ecm if you want to borrow it, let me know.

Hi Rich,  I Will Try One Of Mine And If It Is The Problem I Will Need A Replacement.

[salty1]

Probably time to change out the petcock.  ???  FWIW

[Thunderbolt]

Bert if you have a vacuum pump with a gauge.....pump up just a few pounds of vacuum and see if it holds.  It sounds like what was happening to our Interstate when the vacuum side of the petcock had a small wear hole next to the metal center piece.  It would run slow but when we were two up trying to run 65-70 it would not hold it open far enough to pass the amount of fuel necessary to run that fast.  Or you could try sealing the hole in the bottom of the petcock with the tip of your finger on your left hand if you can do it safely as you ride and see if it picks up.  That weep hole allows the vacuum side of the petcock to move and open the fuel side and blocking it allows fuel to flow easier.  That was my second repair on the Interstate and each of them developed that same wear hole near the center so I gave up and got the Pingel non vacuum replacement.  You just have to remember to turn it off. 

[trout dude]

Bert how many miles is on that bike ?. When DDT'S bike did that we found bad vacuum slides.
 If nothing else works you might want to check them. His had holes all in them.
  Dennis

[97Valk_CT_Euless]

Holes all in them?!?!?  Holy crud! Why?  That's scary.

[Black Dog]

The more I think about it, the more I think it will end up being a petcock issue.  Get yer paws on a rebuild kit, and take yer time rebuilding it.  A member here in Wisconsin had similar issues (High speed running out of gas feeling), and we rebuilt his Petcock, and if fixed his problem.

As I mentioned in my earlier post, my ICM issue was there throughout the RPM band.  Sounded rough at idle, and felt like it was running on four cylinders, when under throttle (swapping the ICM's is still and easy task, and might be a good idea, to eliminate that issue, right off the bat).

Good luck

Black Dog

[Bert AKA,Valkaholic]

I Am Going To Order A Pingel Petcock And See If That Works Also. I Am Tired Of Messing With The Vacuum Petcocks . This Ethanol Sure Does A Number On the Rubber Diaphram In Them.

[ryord]

I had a similar problem with my 2001 standard a few years ago. It felt electrical would just start sputtering very quickly not like a fuel problem. I would pull one plug wire  slightly off the plug and it would come back. I chased it for a few weeks. It turned out to be one of the wires. When one wire goes bad the other wire will not fire  from the same coil. I bought some used wires off of ebay and traced it down to the coil that seemed to be the problem, replaced both wires coming of of that coil. Have not had a problem since. There is small components in the wires. It was heat related and intermittent. Same thing happened on an old Mercedes 280 SE I had for a while. Intermittent plug wire failure, can you beat that. Rick

[HurstRob]

Bert I had problem exactly like you described it. I was my own fault from removing the petcock to replace diaprham. When I pulled the pet rooster the screen stayed put in the tank and unknown to me there was a small rubber tube that slips over the the fuel feeder tube and sits between the main tank level and the reserve tank level. When I pulled the petcock the small rubber tube stayed in the screen and when I re-inserted it floated above the fill tube, bouncing up and down  stopping up the end; sometimes stopping it up real well and other times marginally. It acted like I had water in the tank.

[Bert AKA,Valkaholic]

Thanks Again For The Input. I Inspected The Fuel Line And It Is Clear With No Kinks Or De-lalamination Or Separation . The Petcock Is Not Leaking Either. I Changed The Plugs ,Coils ,Plug Wires , And The ECM Because I Had These Parts Readily Available And It Still Acts The Same. I Am Waiting On A Pingel Petcock That I Ordered And I Will Install It  As Soon As I Receive It. I Believe It Is The Petcock Even Though I Rebuilt This One A Little Over A Year Ago.  The Pingel Is A Manual Valve With No Diaphram That I Will Be Using And I Think My Troubles Will Be Gone For Good. I Will Let You Guys Know Soon, Bert.

[Skinhead]

If you can repeat this condition at will, I would try using your spare key to open the gas cap next time it happens, just to eliminate a restricted vent.  I'd also check the fuel screen on the petcock next time you have the tank off.