After all the work done on the tank and fuel lines you have allowed some crude to pass into the carb. It's either clogging the float jet and not allowing it to open and allow a good flow, or the float adjustment has been disturbed and needs to be re-set properly.

I had the same issue after discovering the tank was full of crud on my 25 year old ride. I added an inline filter along with the new petcock and filter screen. The second filter (clear round inline disc style) has collected a good amount of stuff still getting past the tank filter. I have not had the issue since.

The issue boils down to the carb starving the engine when the float bowl runs out of gas ... Being able to maintain a speed, even fast speed means enough gas is running into the float bowl except when you attempt to quickly increase speed, which draws more gas than the float has and then you stall.

 

Well today I took it apart and cleaned it up. The guy I bought if from in June said the carb had just been rebuilt and the gasket on the float bowl was brand new looking. I cleaned it all up. Nothing apparently blocked or clogged put it back together and put it back on and now its completely unrideable. Before I took it off when I hit the starter button if would catch and fire immediately now it cranks over 2 or 3 seconds before it will start. When it warmed up I set the idle at 1000 rms and if I even look hard at the throttle if stutters and blows black smoke out of the pipes, appears to blow fuel back out of the carb then dies. If I hit the throttle hard I can get it to rev up but it backfires and I get steady black smoke from the pipes and a steady mist of fuel comes out of the carb. The only thing I changed was the float was sitting at .750 inches and it was supposed to be between .725 adn .730 so I adjusted it other than that I didn't change anything. Now what? Any ideas?

 

What all did you take appart? Did you get every jet (main, int, and needle jet) back in the right spot? And you left the idle mixture alone I assume? I goofed up my needle jet one time and all he!! broke loose on my bike.

Also did you get the slide diaphram installed properly?

 

I may have made a mistake and not known it. I was under the impression the idle mixture was the idle speed screw. If I changed it I didnt know it. I'm not sure I even know where the idle mixture screw is. Back to the manual.

 

Nope didnt touch the idle mixture screw but from what I just read it sounds like it may be the problem. Back to the garage.

 

Number 9 in the pic is the idle mixture screw. The idle speed is on the throttle linkage. The mixture is hard to get to with the carb on the bike. Also if you took the main jet and emulsion tube (number 7) out make sure the needle jet (number 5) did not fall out. I have seen this happen. And of course check the seal on that slide diaphram under the top cap.

Trace your steps and take your time. If it is acting that bad it has to be something obvious.

Also if you did not touch the idle mixure leave it alone (for now at least, it may need adjustment later). Get the bike running the way it was before you start changing everything. One change at a time to rule everything out.

 

One disclaimer I will mention is I am not sure what impact of you changing the float level would have. But it sounds like it is within spec.

 

I didnt touch it the first time around but now I have it so f'ed up it will barely run. I went back and took everything back apart and put it all back together but its still messed up. The idle mix screw was backed out 4.5 turns when I first touched it so i screwed it in gently and backed it out 2 turns and it wouldnt even idle so i back it out 1 more and it would barely run then I turned it not even a 1/16 of a turn and it backfires and blows black smoke. There doesnt seem to be a middle ground. I am clearly out of my league so I guess its back to the mechanic for another $300 *** f$#%. Thanks for everyones input.

 

If you got this far with it don't give up!

Black smoke is a sign it's too rich. Gas spitting out of the carb means it's not being metered correctly.

I'm no expert but I'd follow the repair manual step by step to adjust the carb.

With the manual you should be able to set it right and only have to tweek it to run smooth.

Sounds like something may be plugged from the cleaning. There's a lot of tiny areas that can collect debris and alter how it runs.

I know how you feel about redoing something and getting worse results. It can only get better from here .... right?

 

Check to ensure that the needle jet is in right side up, it's #5 on the above drawing and is silver in color. If you look at the orifice in the center you will see that one side is radiused on one end and square on the other end. The radiused end should be sticking up into the throat of the carb and the needle goes into it. If it's in upside down the engine will run as you describe. Float level is critical, when you re-installed the idle mixture screw did you put the spring, washer and tiny o-ring back on it, if not the idle screw can leak air and won't adjust. Hope this helps, don't give up we can work through this. Save the carb if you decide to replace it. Once I get down in SC you can send it to ne and we will fix it free of charge as nobody should have the problems you are having.