I tuned my carb for weeks trying to get rid of that last pop and finally replaced the header gasket; that did it.

It can be aggravating and trying, to say the least when trying to get these things fine tuned.

For example, mine was being a bit sluggish and it was recommended that I add some to the spacer.  Initially when I did that, I thought it helped, but it didn't take long at all to realize that I spoke too soon.  I wound up taking it down a bit past 1/2 spacer, and it has made a world of difference.

Guido wrote on 12/31/69 at 16:00:08:


Naw that '02 will let out a pretty good pop sometimes, and has a little exhaust leak - it's a fair bit faster than the '95 and a lot louder but it only has 1500 miles on it vs.  24k miles on the '95 - one of these days I'll go to work on it - just don't ride it very much and normally quite agressive when I do - I keep pointing  to the '95 and telling the thing that's the way you should behave , but the '02 isn't paying any attention -  in all fairness I'll bet it took 3 or 4 weeks of carrying a little screw driver and tweeking the bike to finally get the '95 spot on - when you get real close it can be a pain - 1/8 or 1/16 turn on the mixture and little on or off on the idle speed - course not too low on the idle or it'll die on you between up shifts when the bike isn't warm yet causing a rear tire skid if you didn't hear it die - all this after you've pickup a half dozen of the cheap spark plugs and did some plug chops - fun stuff!  

And then you go and do something to throw off the balance.  Got it right, put on an Amal carb.  Got right again, put on a Hard Krome muffler.  Retweak every time.

On the way to work this morning the bike did pretty well. Still getting the backfires between shifts though. Also did a weird thing when leaving work. 94 degrees and it died at idle 3 times. Finally had to pull the choke for a few seconds. That's the first time I've had to use the choke since rejetting!!
This weekend I'm gonna shave a bit more off the spacer and see if that helps with both issues.

Don't forget that some crackle & pops are OK.  No harm, no foul.

It is the "BANG!"  that we do not want, that is harmful to the engine.

Unless you have a carb like the Edelbrock, or have something like a Dial-a-jet hooked up ... both of which have an automatic jetting feature in the way they function, it is nearly impossible to totally eliminate every little pop and crackle.   A backfire is the "BANG!", the other is part of the music of a good running engine.