Carb theory 101... im confused.

[TheGoodGuy]

So I read on how it works on teh carbs and I still dont understand.

So from what i gather, fuel sits in teh float/that cover in the bottom. Air comes in thru the airfilter, and on its way to the engine sucks up the fuel by bernulii's principle and it atomises.. or am i wrong.

The reason being I updated my jets and its still bogging.

So I originally had what's in my signature, which worked great for streets but couldnt do freeway wouldnt to 65 on teh freeway without bogging. Those jets were 20, 62.5 and 137.5.

Tonight i put on 20 (kept teh same) and put on 65 and 145. First impressions, the bog was gone. However when i hit the freeway it came back around 70-75 mph (depending on the gear). Now in 4th gear I found it was able to do 80 at 8000 rpm and slight bogging. In 6th at 5500 rpm at 70mph it was bogging a bit (but not as bad as earlier) it gets a bit nasty at 80mph in 6th.

So I guess im leaning out. Next stop 147.5's on the main jet. I should have gotten 147.5 but i figured 145 should be enough to get me thru (in the faq whoever - mjm or piper runs 147.5 with a v&h supersport exhaust). Since im on teh stock exhaust i figured 145's shoudl be enough.

Now I havent shimmed the needles up. I thought the needle shimming controlled the airflow into the carbs, and the jets controled the fuel flow. Am i wrong? The air mixture screw is set if im right at 2.5 turns, but im not sure it was done long ago.

I can ride street, so i can go for tommorow's ride, but i have to get her 'freeway' capable again.

[The Buddha]

OK you can make 8000 rpm in 4th and 5500 in 6th ... dead giveaway sign - rip in diaphragm. You'd probably have to seriously look for it, cos it would have to be tiny ... and it started doing this all of a sudden right ... diaphragms are tough little guys (OK I am talking the old style - not sure if new is different), but some random piece of dirt can put a tiny nick in it ... Look for it, worth checking out.
Cool.
Srinath.