new muffler affects gas/air mix?

[Ruckass]

So I've installed my new muffler and want to know if and how it effects the fuel to air mix. There are two new changes with the muffler, 1.) is the new muffler has better air flow 2.) a slightly larger diameter pipe than the stock one, so better air flow as well. This has created a better downhill speed (less backpressure I guess) but marginally worse off the line and uphill power/speed. I cleaned the plug when I installed the muffler and checked it after about 50 kilometers. Its a little oily but not terrible. So my questions are, 1.) does the muffler effect the fuel air mix 2.) do i go to a smaller main jet to correct the rich mix?

Ruckass

[pain merchant]

When you get a different exhaust, usually the benefits are increased air flow. Along with increased air flow, you gotta give it more fuel. If you can breath better, you gotta give it more air. If you give it more air, you gotta give it more fuel. All three of these work hand in hand and the mixtures are critical.

[Ruckass]

ok, but the plug is oily which would indicate a rich mix, therefore a smaller jet, no?

I've already got a huge K&N airfilter so my airflow is maxed out. Its basicaly wide open air intake and I'm running an 85 jet.

Ruckass

[chanito]

Ok this is complicated, so bear with me, yes more air more gas, however fluids have their own rules, when you increase air flow, more gas and air mix go into the cylinder, BUT, inertia comes into play so the mixture has to do a sharp turn to go into the cyl, and wants to go in his merry way out doing another sharp turn to go out into the exhaust, however the gas does not want to cooperate and just hangs around the top of the piston untill the exhaust valve closes, so yes you do have a rich condition, the best way to prevent this is to create something call a swirl, and that is why in "some cars" those turbonator or tornados work by preventing the gas from separating and makes inertia not a factor inside the cyl, we are not that lucky, unless Abe designs one for the ruckus, my sugestion will be to the next smaller main jet.
Let us know either way, i am waiting for my jets to reinstall my intake, and then my home made exhaust, so your feedback will be welcome ;D

[Ruckass]

I dropped the jet from an 85 to an 80. Seemed to work fine till I hit the really high RPMs and high speeds. It bogged at about 45mph going down a hill. I'll check the plug again but I think I have to go back up to an 85.

Ruckass