black sooty plug

So here is the deal. Carbs were gone through, squeeky clean. Pilots adjusted out to 3 turns. Float levels are dead on. Spark plug cap resistance is at 4.88 ohm on cylinders 2 and 3 . 4.78 when hot. Resistance on spark plug cap 1 and 4 is 7.47ohm. Pilot jets are all the same in the carbs as well as the mains and needles.
Number 2 spark plug is getting sooty and black. All the rest are nice and light tan looking. Even number 3 which runs off the same coil is good. I can turn the pilot jet all the way in on #2 and the engine just purs away. No noticeable change. Wierd.
Maybe the enrichment plunger for this carb? Any suggestions?

 

Yup - sounds like the enrichment circuit (aka choke but not really) on that one carb is probably your culprit. Could be sticking up a bit, or there could be some crud buried deep in the carb in it's circuit.

 

Just found a very small piece of something down inside the enrichment plunger. Dont know if that was it but I will find out in a couple of days. I will post up and let you guys know. Now I need to resync the carbs again. Good thing I own them and do my own work. Sync should show me something also. If the 1 and 2 are out of sync then that was the culprit.
Is there supposed to be an 0 ring in under the bottom of the plunger of the enrichment circuit? This one did not have anything down in there for a seal. Just the plunger bottom

UPDATE; I found the sync to be off on cylinders 1 and 2. Hopefully I have found the problem. A nice long ride will tell. I will let you know the findings.

 

Ok, had to take the carbs off. Looks like some water had gotten in the number 2 carb bowl and sat there for quite a while. The pilot jet which is supposed to be a 36.5 is now a 40 to 41, by the looks of it. Hence the sooty plug. Any one know where to get a 36.5 pilot from? For a hitachi carb.

 

Im not 100% positive sam but I think I just seen them on "old bike barns" site.

Hope this helps .
Ridz

 

Try here: www.cyclewareables.com
I had good luck, 5 bucks a pop. But wasn't looking for that size.

 

No luck so far. Like looking for a nedle in a haystack. Any more suggestions.

 

Try these guys:

http://www.motorcyclecarbs.com/