Diagnosing Starting Issues after Carb Work

[Mideval135]

Hello all, I aquired a 98 Valkyrie two years ago, and rode it consistently since I bought it. Put about 25K on it since. I really love this bike, and can't wait to be riding it asap. However, I am in desparate need for help diagnosing starting issues, so I will try to keep this short and simple as I can.

Current issue(s): Bike takes a long time to start (when enriched and won't fire at all when it's not enriched), and once it's running it fails to idle properly. A couple attempts and then the battery dies, so I have to try again the next time while the battery recharges.

Work I had done up to this point: Partial carb rebuild (including float valves and upper fuel rails and seals), replaced o-rings on the intake pipes, new petcock, and new throttle cables. The reasoning for a partial rebuild is, while I was replacing the jets, one of the low speed jets broke off while I was replacing it (was able to remove thankfully with needle nose vicegrips). So to not push my luck further with a worse break, I decided to not touch or replace the high speed jets or the pilot screw. I took careful measurements of the sync screws and placed them back once the new fuel rails were in place.

After all that work was complete and the bike was reassembled, I tried starting the bike. And that's when issues start. First couple start, it seemed that only one bank of cylinders would fire. One time, on the right, another time, only the left. Next time, all cylinders fired. Then the battery would die. Another night recharge and the next day the bike fires up but fails to idle while it's enriched and it just plain dies when it's not enriched. This past weekend was the most recent attempt to start with new fuel and some SeaFoam. What baffles me the most is, the bike was running prior to this journey. It was running and I was about to take it for a ride when I noticed the fuel leak. And because I kept the same measurements of the sync screws and didn't touch the pilot screws, have spark, good fuel, and a working battery, I am at a complete loss.

I've almost come around to tearing the bike apart again to troubleshoot, but I don't know what it would accomplish since I don't know what is causing the problem to begin with.

I could really use some seasoned expert knowledge here.

Thank you all

[98valk]

battery could be bad. ignition needs minimum 10.5 volts to ignite.  engine will turnover at lower voltage.

idle mixture screws should be checked.

warmer temps idle mixture screws too rich and using enricher/choke, now really really too rich. try not using choke and check battery voltage while hitting start button. seafoam a'30s product, has chemicals in it that can ruin carb o-rings over time. I use TC-W3 a modern safe cleaner/lubricate. see here  https://www.ls1.com/forums/showthread.php?t=91206

[KTRT]

I had to remove and do the carbs last year, also for a fuel leak.

Afterwards I did had some problems getting it to run. These were caused by issues with the fuel Petcock, and more stupidly because when I put everything back together there was a kink in the fuel hose.

Check the vacuum hose to the Petcock, unless yours have been modified. The situation you described reminds me way too much of a fuel issue.

[John Schmidt]

If it won't idle that often indicates plugged(partially or fully) low speed jets. You didn't say if you had put the carb bodies in a solution to clean them using an ultra sonic cleaner. If you're going to go through the trouble you listed to clean them, that's good but you did only half the job. You might get some good results with the stuff 98Valk suggested, give it a try...easier than tearing them down again.

As for the enricher/choke, don't be so quick to use it all the time...especially in warm weather. These bikes often don't need it and...do check the battery draw down upon starting. If it drops below 10.5vdc, it usually won't fire. It has enough to turn the motor over but not enough juice left over to fire the coils. If the bike fires just as you let off the start button, that the first indication of a bad battery.

[Pluggy]

A good troubleshooting step is using is a "mini tank".  eBay has ones with the (about) 12 oz bottle, hose, and a valve. 

If a Valkyrie is running poorly, remove the tank and hook up the mini tank.  If the bike returns to smooth running, we can turn our attention to the fuel flow items: filter, petcock and hose routing.