FUEL STARVATION OR ICM?

[O-B-1]

My Phat Gurl has started cutting out at 3,000 RPM or at 3,600 RPM intermittently.

1. Checked the vacuum hose from #6 intake to the fuel petcock.
2. Fuel petcock diaphragm replaced at Inzane XV last June by Big BF.
3. Checked the fuel vent line for obstruction, even disconnected it for awhile to check for that.
4. Ran a full can of B12 in a full tank of fuel for 1/2 tank at the trouble RPM, let it sit overnight then ran it to reserve next day before refilling.

Maybe the fuel side of the petcock is being obstructed?
Could the fuel line be swollen internally?
Could it be an ICM (Ignition Control Module) issue?

5. Ordered a Pingel 1311-CH this morning.

I am now hoping the one I ordered won't have the reserve leaking when in full position is used that some have reported lately.

QUESTION - Dan Marc valve... I see some have successfully used the 0.125" (1/8') orifice valve, why not use the 0.250" (1/4") valve? Isn't the OEM line 5/16"?

[The emperor has no clothes]

It's hard to tell from your pic. But if you have the chrome engine hangers, I've had that interfere the the fuel selector and not open the valve completely. And I know of no good reason not to use the larger danmarc. I have for a couple years now.

[98valk]

running rough or cutting out I lean towards
electrical issue.
check all ground connections,
check plug wires ohm reading, each plug wire has a resistor in it, make sure dielectric grease is not on the plug tip or contact inside of plug wire.
check plugs, ohm readings, plugs correctly tightened?
check all coil electrical connections.

never heard of an ICM going bad.

[Ricky-D]

Sounds like a failing alternator and possibly combined with a bad battery.

***

[Blackduck]

Is it the same hot or cold?
Will it run above 3600? Do's it only give problems in that rev range?

[Firefighter]

Does the engine power get mushy like when going on reserve or is the engine missing like quick misses? Usually you can tell the difference in fuel or ignition on the Valk.

[O-B-1]

Sounds like a failing alternator and possibly combined with a bad battery.

***

The battery may need replaced. I haven't done so in the 4 years I have owned the bike. I think it was fairly new when I bought the bike from the previous owner.
 
She has 88,000 on her. You think the alternator would start failing at that point? Brushes?

[O-B-1]

Is it the same hot or cold?
Will it run above 3600? Do's it only give problems in that rev range?

It is intermittent. Seems to be when hot. Used to be just around 3,000 RPM, but now starts happening and won't smooth out with more throttle like it used to.

[O-B-1]

Does the engine power get mushy like when going on reserve or is the engine missing like quick misses? Usually you can tell the difference in fuel or ignition on the Valk.

Seems mushy, like it may be fuel related. That's why I ran the B12 Chemtool through the system. I have ordered a Pingel petcock. I suppose replacing any rubber line while the tank is off may be a good idea.
I will start checking the electrics while awaiting the arrival of the petcock.

[98valk]

Sounds like a failing alternator and possibly combined with a bad battery.

***

The battery may need replaced. I haven't done so in the 4 years I have owned the bike. I think it was fairly new when I bought the bike from the previous owner.
 
She has 88,000 on her. You think the alternator would start failing at that point? Brushes?

consider replacing the intake manifold O-rings. OEM is Buna-N starts to flatten over the yrs, might be vacuum leaks.
search for size, look for viton material, last longer.
check all rubber connections btwn carburetor and manifolds and airbox. screw clamps get loose, I tighten them and than a dab of black RTV on thread and nut to stop back out.

[John Schmidt]

Have you possibly been messing with the fuel line from the petcock to the "T" that feeds the carbs? Keep in mind, since it's gravity fed it all has to run downhill. Some riders have installed a slightly longer fuel line to make it easier to attach to the petcock. That often causes a low spot to develop and especially once it's hot. Also, if you have a bad diaphragm in the petcock, it will restrict the fuel flow. Replacing the cover set often creates problems for someone that doesn't use caution. Keep us posted as to what you find.

[O-B-1]

Ordered and installed Pingel and it works now. I have a 1/4" Dan Marc on hand. Need fittings and relay. I also replaced the NGK Iridium plugs with standard NGK fare. The Iridium ground electrodes had eroded quite a bit over the 50,000 miles they have been in there.  It sounds as though it may have a restricted slow jet in one of the carburetors. I will have to save up to afford the services of Attic Rat, I suppose.