If you haven't pulled the recoil cover and cleaned the face of the pulse coil and around the flywheel you might try that also.

 

Thanks OPT, I will try that too.

 

Cleaned the face of the pulse coil, flywheel was sparkling clean save for a little grease from the starter drive. Rechecked the valve lash settings just in case, and they are good (.006). Pulled the plug and it's running rich, plug is black. It has the proper main jet according to the book (Haynes manual: 120 main jet for engine serial numbers ending in 08) Main jet looks factory, not like someone ran a welding tip cleaner thru it or anything. It has the proper needle and I've run the needle in all 5 slots I am also going to pull the clutch cover and look at the belt and clutch sheaves. Is there a spec for the pulse coil? yellow to yellow with red stripe ( I think) It just feels like it's fuel related to me. I could be wrong, I was wrong once before in my life. I may spring for the next smaller main jet just for the heck of it........
ETA: I just found out there is an air jet in the top of the carb, I'll make sure that's not plugged too.

 

Through all your posts you mention cleaning the carb,new fuel pump,etc,but if you haven't installed a carb kit or at least a new needle and seat,float level isn't parallel with the carb body,this could be cause of rich running, dark plugs.Plus if float arm and pin are worn and wobbly,this is another thing that people overlook that doesn't come with carb kits. Pulse coil resistance between the two wires is around 97 ohms resistance.

 

Figgered I should update this thread, been super busy at work and haven't had time to work on it, but....

I should have mentioned that for me, a "carb cleaning" includes cleaning the carb body, bowl and all jets, remove float and check float pin, float needle (with a magnifying glass) and seat and float height. So all of that stuff is good to go. I did however hook up a clear fuel line to the bowl drain and checked the fuel level with the engine off and I also jacked up the back end, properly supported it and ran the motor up to full throttle and watched the fuel level and it looks great.
So I put in the next smaller main jet (stock is supposed to be 120 and I have a 117.5 in there now) and put the clip in the middle slot of the needle and it seemed to improve a bit. I moved the clip up to the top slot of the needle and leaned it out a bit more and it seems to be running great now. I did try the second smaller jet, but it seemed to go back to what I had with the stock main jet. I think I have it fixed now.

I am going to run it a bit and do a plug chop and see what she looks like.

Thanks for all the help OPT!!!

 

Glad you're starting to get it running better,BUT just my old opinion again on this one. Maybe I was a mechanic too long or simply because I had easy access to carb parts,etc,but anytime a carb came off that I suspected of having problems it got a new needle and seat always. This part is the hardest working,most wear related item in the carb other than the float and pin and carb slide. It's almost impossible to "measure" float needle wear and could be some of the problems you're having on fuel and having to go back and forth on jets and needle position changes. Plus on top of that I was lazy,I hated to have to go back into something twice..Guess I'll just leave it at that and hope you get it running right to suit you!

 

I know what you're saying, unfortunately this isn't my machine or I would have done exactly what you suggest. I'm working on this machine for a friend who is on disability (she uses the wheeler to get around her property and do her garden work) and has a limited income. Needless to say when I show her a part as small as a needle and seat and tell her it's 35.00 from the dealer, she has a hard time understanding why it's so expensive. So I did what I could to keep the costs down as I diagnosed the issue, including eating a lot of the diagnostic time just to help her out. In the meantime I found the Mikuni needle and seat on ebay for 23.00 and have one on the way. I'll update the thread with the results.