Spark plugs fouled after setting carb float levels

Hi guys, saw I was running lean when I first got the bike. I did a very quick carb clean because a few of the jets were clogged and also saw that the idle mixture screw was out about 4 turns and the bike was still running lean. To me this meant either the valves or carbs were really hecked up, or both. Valves were done and it actually made the bike run a bit leaner.

I checked the wet float levels a few days ago and saw they were very much not in spec. My Cyl. 4 was running the best and its float level was around 6mm. The other 3 were at least 9mm. Spec is 3mm so obviously some work had to be done. So went through the process of getting them all at around 3mm. Got everything back together with the idle mix screws at 2.5 turns. Started the bike up with the choke and everything seemed to be running fine. If I pulled back on the choke (even once the bike was warm) the RPM would slowly drop and the bike would die. I could keep it alive with a bit of throttle but if I tried to blip it too hard it would bog. If I slowly increased the RPM it would rev up higher. I left it for the day.

Now today, trying to start the bike it wouldn't fire and then backfired really loud which scared the crap out of me haha. Checked the plugs and I'm pretty sure they got fouled. Could smell gas and the plugs that were lean (white) before were now dark/black.

I'm going to change the plugs tomorrow and really lean out the idle air mixture. I'm thinking I'll put them at 1.5-2 turns out. Anyone have any tips/advice?

Thanks!

 

Have you rebuilt the carbs?
Have you verified that the enrichment wells are clear?
Have you synced the carbs?
Have you checked for Vacuum leaks?

 

Not a full rebuild no.
I am going to.
Bench Sync.
No leaks on the Carb to Engine boots but haven't checked anywhere else.