Running rough.

[valkmc]

97 Valk giving me a problem. It has recently had carbs rebuilt, has recently had a new OEM starter button and all regular maintenance completed. Never experienced this problem so before I bother my mechanic I would like to fix the problem if I can:

Drove the bike to the gym (12miles) a few days ago and it ran great. When I started it the famous clicks from the solenoid happened but it started. Started home and about halfway it started to run rough. Similar to running low on gas. Switched to reserve, did not help.
Made it home, I  carry an OEM solenoid so I switched it out, checked all of the battery contacts and all was good. Put the battery tender on and within 3 minutes it went from red to green. Started her up ran to the gas station filled it up and drove around town for about 30 minutes ran perfect. Went to Daytona for the week end but because of the issue I took the Wing. It sat for several days came home and went to the gym with her. Exact issue again minus the clicking solenoid. It began running rough again half way home.  started right up and ran fine this am. Did not take it for a ride. ANY IDEAS?

[WintrSol]

I'd start by testing the battery. Then use a reasonably accurate Voltmeter to measure the battery while it is running, both at idle and revved to about 3000rpm.

[Pluggy]

I used to work in Daytona and parking a motorcycle in the heat made a lot of our batteries age rather quickly.  Let me suggest you make measurements before you take the entire bike apart.  You can temporarily wire in a small DC voltmeter like this one.  Our bikes needs around 12.5V (minimum) at all times to work reliably.  Measurement is the first step in troubleshooting.

https://www.ebay.com/itm/192375098807?_trkparms=amclksrc%3DITM%26aid%3D1110025%26algo%3DHOMESPLICE.COMPOSITELISTINGS%26ao%3D1%26asc%3D266070%26meid%3D9cd422e69dca434382288ccd8736359e%26pid%3D101506%26rk%3D15%26rkt%3D25%26sd%3D124979828100%26itm%3D192375098807%26pmt%3D1%26noa%3D0%26pg%3D4481478%26algv%3DAlgoIndex5SimRanker%26brand%3DUnbranded&_trksid=p4481478.c101506.m1851&itmprp=cksum%3A1923750988079cd422e69dca434382288ccd8736359e%7Cenc%3AAQAJAAAA8PUN0fWkGeKRy%252FfsmLQSJISD%252FYy8GIblM3myMCKCBhHbNjiQ2FeZ0bDXOHfd8lPfEoVdK5WPFvoUhwS6%252BnjuQ309uhek--NZVZWutl1MbeD7sL7dYi9HsJ%252Fn%252F4povl0WlFOCX%252FQIzVxa9KaO1DfbnL45uwfUw2w8z%252B6QxX8tNbfZm0vOAPYdiqNalKwEIyfvyjjs1xIgR0ZhtqJWR66eJvo5kgM27G4psPnuzJQdnrVGGOD3rlCqKk6q34rs1LF%252BwnI8UF8tD0dhYInBkwBjRjrrt%252BJ3jq6TXgtJrh%252FakE3MozWMP2TNjWhWzhbj2UfA4Q%253D%253D%7Campid%3APL_CLK%7Cclp%3A4481478&epid=15010358739&itmmeta=01HZPZH5QKVZZVT2A7MW7WQTTK

[Chrisj CMA]

Sounds like early symptoms of impending petcock failure to me.

[John Schmidt]

Voltage checks are quick and easy and don't involve any disassembly. What you describe however sounds more like fuel delivery issues, possibly the petcock or possibly a plugged or partially plugged vent line coming out of the back of the tank. An easy check to see if it's clear, only takes baby sized hands and 14" fingers.  Next time out, try leaving the cover loose on the tank. If the problem goes away, then your vent hose is most likely the source. If not, as Chris says then I'm guessing you're a candidate for either a new petcock or cover set to repair the old one. If you replace it, consider moving away from the OEM unit, it appears to be the weak link in the fuel delivery chain on these bikes.

[Jims99]

I agree with John. Sounds like a fuel issue. Two things to add, make sure there’s no water in fuel and check fuel line is short and straight. If too long and drops down and back up, air bubbles can cause problems. Trick to check ent line, close a tie wrap in the lid to allow air in.

[Pluggy]

I agree with John. Sounds like a fuel issue. Two things to add, make sure there’s no water in fuel and check fuel line is short and straight. If too long and drops down and back up, air bubbles can cause problems. Trick to check ent line, close a tie wrap in the lid to allow air in.

Good things to check as the fuel tank was removed when the carbs were rebuilt. The tank may have been reinstalled incorrectly. 

[SunshineNomad]

Check the gas tank vent. When my tank was reinstalled, the vent line was pinched and caused exactly what you posted.

[Chrisj CMA]

Gentlemen, who has a voltmeter on their Valkyrie? It seems useful. Many electrical/electronic things fail when the heat goes up. Motorcycle starter motor, Ford backup camera, and the ignition module in my old Pontiac all failed when hot and worked when cooled off. The voltage regulator in my wife's car did that, too.

A hot day and hot engine might cause the valkmc bike to stop generating while on the road. A voltmeter would tell the rider. My Valkyrie didn't came with a voltmeter, but it makes sense to install one.

Saved my butt a couple times 

[Hook#3287]

Check the gas tank vent. When my tank was reinstalled, the vent line was pinched and caused exactly what you posted.

This. 

[rug_burn]

Nicely finished walnut, wow, nice.  Just keep it out of the rain.

But as to the low voltage issue on the '97 tourer...:
  That's exactly what I got, a '97 tourer, and mine is having the exact same issue- and I think is my alternator.  It runs off the battery okay, but will run it down in about an hour, and this with the LED headlight (H4), mentioned here often, which draws much less than the regular halogen one.   
   So- I charged it up to about 14.6 v. right off the charger, which is good.   Next morning it read 12.7 volts, which is normal for a good battery, and I rode it for about 45 min., where it read about 12.3 volts.  Which means it ain't charging.
  Hence, the alternator needs new brushes, at the very least... or maybe I'll just spring for a new alternator.

[-mike-]

I'm in with the tank vent being the culprit.
I'd even bet the vent hose has been pinched between tank and frame when mounting the tank back.
Don't ask why I know..... 

The simple test by running the Valkyrie with a cable tie placed over  the filler cap gasket will tell the tale

-mike-

[WintrSol]

I always start with the low-hanging fruit: weak battery, pinched vent qualify there. Next up is bad/weak charging or petcock. First thing you know it, you're spending $$, so start cheap; it only gets more expensive.

[valkmc]

I always start with the low-hanging fruit: weak battery, pinched vent qualify there. Next up is bad/weak charging or petcock. First thing you know it, you're spending $$, so start cheap; it only gets more expensive.

Good idea. Battery was weak so I replaced it. Charging is good and nothing is pinched. So petcock is next.