Ran good, but started backfiring and bogged down 2 hrs later

I've had it on the road only 1 week after rebuilding and customizing it, then tonite on the way home, things fell apart. I have followed all the advice and procedures on this site for carb rebuilding, colortuning and synchronizing. It started making popping noises out the exhaust when coasting down the road and twisting the throttle slightly. I can make it go away by adjusting the enrichment lever about 1/4 open...does this sound like a lean setting and needs colortuning again? Tonite it ran fine for about 2 hours, then on the way home, it started running rough and more backfiring. I thought I was out of gas but switching to any position did not help. It felt like it was running on 2 cylinders and I had to keep the revs above 4k otherwise it would bog down even worse like it was going to stall. Got it home and just parked it for the night...will look at it tomorrow. Hoping to get some ideas on where to look. The petcock was rebuilt, tank coated inside, and in-line fuel filter added. Fuse panel replaced. Carbs totally dismantled, cleaned, and new parts installed, adjustments done a la Rick , new carb boots, and plugs. Plug wires and coils checked out good but that was about 2 months ago, when I was putting the bike back together. Help?...please?? :cry:

 

sure sounds fuel-starved...

did you check the fuel line for possible kinks? old fuel lines could collapse once they get warm.

might check the spark on all 4 again, just to be sure.

 

And check your inline filter. Is it the clear one? The Visu? Check it very carefully. It doesn't take much to clog those things up, especially if there's any tank lining residue making its way down the fuel lines.

 

What a night...spent more time sitting on the side of the highway than riding...AARRGGHH. I took the petcock apart and found a piece of the lining pushed out by one of the screws embeded inside the petcock. Cleaned it out and reinstalled. Filled the tank up and started riding. About 5km down the road it started bogging down again. Although the inline filter was new from 2 weeks earlier, there was some crud in it so we limped to a bike shop and bought one of those brass high flow filters and put it in. As well, we checked the fuel lines, they were clear. They were also new from a month ago. Back on the road, another 2 km and time to pull over, bogging down. The fuel filter was empty. We disconnected the fuel line from the petcock and gas flows freely on PRI and also on ON when vacuum applied to it. Blowing into the fuel line to the carbs (love the taste of fuel...yumm), there seems to be a restriction although it could be because of the carbs...any ideas? If you let the bike sit for 5 minutes on PRI, the carbs fill and away you go but only until they empty. No fuel flow enough to keep it running...even when left in PRI. Where is this gremlin? When I find him, I will crush his little skull! In the meantime, any other ideas where I should look? We trailered the bike home and I'm gonna get at er this afternoon. Let the fun begin.

 

Phil, maybe you have a float that gets stuck in the "up" position?
Another thing to think about - try riding with the gas cap open (be careful, of course)... I remember reading that some X's had vented caps and some didn't... Maybe something's amiss with the tank vent...

 

Stereomind:
I think the bike might be fixed now, and I've once again realized how important it is to listen to your beloved. She always reminds me to keep it simple as it's likely a simple solution. Well, my good buddy Ted (XJ750 too) came over with the idea to replace the new fuel hose with another one just a tad longer so we could reroute the line. I thought it looked fine and no sharp bends but applying the KISS principal, we changed it. Lo and behold, the filter filled in seconds and the carbs were full shortly after (this usually took up to 5 minutes). Voila!!! No more bogging down. All of the folks here that kept saying it was a fuel problem were right...just didn't keep it simple enough for me. Gotta stop complicating things I guess. Again, this is the best website with the best people on it!