Strange Choke (fuel enrichment circuit ) problem - Long

Hi everyone, another newbie here I’ve been lurking around these forums for awhile but this is my 1st message. A little back ground I use to ride when I was younger up to about 1980 haven’t really ridden since. (Other then a few friends bikes but few and far between) I got the bug again when someone in my office started riding to work. I found a 82 650 Maxim its been in a garage since 91. In nice cosmetic shape so I did the normal stuff Battery, fluids, filters, brakes, wheel bearing repack, (Did auto mechanic work in a previous life but now I’m in the computer field.) Ok now the carbs… Pulled them apart (left them on the rack) gummed up as you’d think but since the bike was stored without gas not as bad as I thought they would be. One float needle was stuck to its seat… replaced it and its seat. Everything else looked like a good cleaning would do the trick.
That means I did a “fair” cleaning but I as am the father of 3 young children (started late) my wife only tolerates so much time tinkering with my toy. I cleaned the intake boots then ran a thin later of black hi temp permatex around them for good measure. Mounted the carbs back up and primed the carbs & gave it a try. Well almost nothing… it sounded like it wanted to go but nada. So off with the air cleaner cover shot of starting fluid & away she went… for 2 seconds… this went on for a bit then when playing with the choke ( I know fuel enrichment circuit but choke is shorter to write) I must have left it off when trying my starter fluid routines (plungers down) the bike started & stayed running throttle was a little sluggish the 1st couple of minutes but responsive after that. Ok so that brings me to a couple of admissions and my problem of course. 1st admission is that I don’t believe that my petcock is working correct & needs to be rebuilt. I installed some clear fuel line & found that the bike only stays running while in Pri position if moved back to ON the line runs out of fuel like it was turned off. The vacuum line to the tank does have vacuum. I know that maybe the floats could be a little off but I wouldn’t think so far to completely shutdown the fuel plus once warm the bike runs great in Pri. 2nd admission is that I haven’t adj. the air/fuel screws at all I can’t seem to drill out the brass plugs. I bought 2 new 1/8” titanium tipped drill bits & still no go they barely scratch the surface of the plug. So I would like to of course be able to start the bike without my long ritual which means figuring out why its not getting the added fuel when fully choked. Now I know that circuit is doing something because warm if the bike idles at 1500 RPM when I add a little coke it’ll sail north of 2K if I add full choke it stumbles and dies. Sorry I was so winded but I wanted to give as much info as I could. Sooooo any guesses of what to look at next. Oh yeah almost forgot I didn’t try any type of carb syncing other then just checking that they look good on the bench. The bike has 19500 miles on it & I have no idea if the valves were ever adj. By the way because of my family I only get to try repair/maintance work on the weekends my replies may not be quick. Thanks for reading this -Lou

 

First off welcome! Second, Now That's how to write a post with history of what has been done!!!!! If I was Drew Carey I'd give you a thousand points!
Sounds like you are right about your petcock. My guess is that the diaphraghm is cracked. This can be fixed with the K&L kit. It would be nice to remove the mixture screws and clean that portion of the carbs but since it runs fairly well this may not be necessary.
You description of the choke circuit's behavoir sounds like it is working as it should. I would fix the petcock so fuel flows in the on position and then send us a description of how she runs. BTW the diaphraghm is n the back side of the petcock. Remove the back plate and see if there are any cracks in the black rubber piece that goes across the back. This is the diaphraghm. If it has a crack then the vacuum can't pull it to the back plate and allow fuel to flow.

 

I agree with the first reply completely, you may also want to check to make sure that the vaccum passage is clear and clean. I have seen them before where they get plug up, it's a small passage inside the petcock that the vaccum travels thru. Check it to make sure you are getting good floe so the vaccum can work properly, clean out all passage ways and make sure it clean,clean,clean,

 

Whoa ... I need you to tell me what and where you tried drilling!!! The anti-tamper plugs are BRASS.

You don't need special drills ... and, the brass is so soft you could almost poke a hole through it with the shaft of a Q-TIP !!!

People don't have problems drilling the plugs ... they have problems drilling through the plugs and damaging the tops of the pilot screws.

Let's get on the same page and Zero-in where and what you are trying to drill. You might be trying to drill a pressed-in ball bearing that seals a spot where the carb body was drilled for a fuel passage.

 

Yeah I know it's a round brass plug next to where the plunger for the fuel enrichment ciruit is on each carb. Don't get me wrong it has scratch the surface but not much. Also somehow i missed the stickies at the top of this forum. The one which talkes about instant start. Maybe my starter is drawing too much current? It seemed fine so I never opened it up. People in these forums talk of a BIG BLUE SPARK mines Blue but not overly big (ahh that didn't sound good) maybe week coils? only giving me problems on startup. Thanks Guys

 

Basically the BIG BLUE SPARK just means a crisp blue spark rather than a dismal yellow one.

You didn't mention (or I didn't find) whether you have put new plugs in. If not then definately do so. The others have covered most other things to check quite well.

If you put the petcock on prime for thirty seconds will it start by itself. If it's choking up with full choke then it sounds like it's running a bit rich. If anything this should help cold starts as long as it has fuel.