I don't remember pulling it out and I sure doen't remember putting it back in.  

I DO remember looking through the bore of the carb and seeing a small diameter tube that was very firmly attached.  I don't think that is the neede jet.

Guess I'd better go out to the garage and see if I can get access to the carb and check it.

So is the needle jet flush with the bore?  

I just removed the intake boot and looked into the bore from the back of the carb.  I saw the vacuum diaphram, lifted that up, saw the jet needle slinding into a hole in the bottom of the bore.  The hole it slides into is the diameter of the needle and is in the center of a darker piece of metal that is flush with the bore of the carb.

Does that sound right?  

Steve

and what's interesting is if you put the main jet in (at least the small round) with out the washer that tube will pop up and sort of stick to the jet needle when it goes up - you talk about running rich - D' ammmm

need to be fairly cafeful with that dang mixture screw - little devils can sure jam easy enough - depending on how high you idle is set the mixture adjustment may be subtle - you have a tach ?

You said that you did not remove the pilot jet or the pilot adjusting screw when doing the cleaning before.  You really need to do that.  Take EVERYTHING apart, soak it again, if you have any tiny tube brushes then use them to clean passages and/or blow ALL passages out with compressed air (WEAR EYE PROTECTION!).  

I think you will find that after doing all of that the engine will respond the way it is supposed to when you turn the adjusting screws.  The whole thing should take about 2 hours.

We look forward to a good report afterward.
It will not take much more time and you will be able to do it with a blind fold on.  Kind of like when in the military and learning to disassemble and assemble a rifle while blindfolded...with a stopwatch of course.  
By the way, I was the fastest with the rifle...no brag...just fact.

Yes, the adjusting screws will come out.

I think I've just about got the backfiring problem solved.

To review, I had installed a Dyna muffler and a 152.5 main jet. But I still had some backfiring.

Then, I tried removing the idle mixture screw.  I stripped the slot in the screw.  So I had to give up on that.

I got a 55 pilot jet (thanks Reelthing). I removed the stock jet sprayed a lot of carb cleaner up the pilot circuit, and installed the larger pilot jet and a 155 main. The engine still backfired.

I'd read here that an exhaust leak could cause backfiring. So i went out Tuesday and bought some exhaust sealant, planning to put it on Saturday.

Today I got a K&N filter from Performance International (thanks for the tip pgolden).  I installed the filter and decided that try the engine.  It caused even more backfiring.  That didn't suprise me because of the increased air flow made the mixture even leaner.  

As it was running I noticed that the exaust pipe was getting really hot.  The garage was sort of dark and the exhaust was actaully glowing near the head.  

I decided to check the head to exhaust flange bolts after it cooled down. They were indeed loose. I pulled out the torque wrench and tightened them to 19 ft-lbs. Looks like I didn't tightened the bolts enough to crush the new gasket when I installed the new muffler.  

I started it up again and the backfiring is almost gone. The engine runs much smoother.  I hope to take the bike out for a ride Saturday and give it a good test.

Thanks to all those that helped.