I usually just figure this kind of thing out by trial and error but like to see if any of you have any input. My bike is a 97 Superglide. The only mods that I know of are a K&N type air filter and Python3 2 into 2 pipes. It currently has a 45 low and a 180 high jet with a NOKK needle. It runs fine except that when you close the throttle (think compression braking) I get some very light exhaust backfiring and if I roll back on the throttle it will backfire out of the throttle. Otherwise it runs fine, pulls hard, and doesn't backfire.
When trying to set the idle mixture I can get it to stumble when turning it in but I can back it way too far out with no affect.
I assume that I need to put a larger low jet in it. Do you think a 48 will be too big? How about shimming or changing the needle?

 

Have you checked it for any leaks around the intake? Jetting sounds good to me.

 

48 idle jet and 190 main with a needle shim should fix it.

 

I suspected an intake leak so I replaced the seals and the carb boot. I used the paper trick on the exhaust gasket area and didn't find any leaks.
I have a kit coming with both of those and some shims. I'm not sure about the 190 because it runs fine on the top end now but I guess I'll see,

 

It can still run fine, if a little lean. I've always believed it's better to start a little fat. And, it does sound like your low jet is a bit small, at least.



Fredericksburg? I live in Falmouth..... And should be riding again soon.

 

2 into 1?
I have always experienced Backfires with a 2-1 exhaust...Certainly when accompanied by a Dual Fire Ignition. Betting a set of staggered duals would Make the Backfire go away...Probably Not be a Performance gain tho.

 

Id try the next size up pilot jet.

 

Thanks for the replies. I'm going to start with a bigger idle jet and then shim the needle if it needs it.
Axis,
Let me know when you're riding again. We can check out some of the roads. I know a few and am always looking for new ones.

 

I run a 48 and a 190 in my evo

 

I have those same Pythons and have to say they are a real good 2-2 for an Evo. They really let the motor breath.

Woods W6 uild yielded 93/85
W8 yielded 95/93
And they sound real good. Old school....