Several jet vents have hardly any flow coming out

If only one section of your jets is operating and the others are not, there could be several potential causes:

1. Clogged jets: If the non-functioning jets are clogged with debris or mineral buildup, they may not be able to produce bubbles. You can try cleaning the jets with a jet cleaner or a solution of water and white vinegar.
2. Airlock: Airlock can occur when there is air trapped in the plumbing system. This can prevent water and air from flowing to the non-functioning jets. You can try running the pump on high for several minutes to see if this will dislodge any air bubbles in the plumbing.
3. Pump problems: If the pump is not working properly, it may not be able to provide enough water flow to the non-functioning jets. Check the pump to ensure that it is working properly and producing sufficient pressure.
4. Damaged or worn out jets: If the jets are damaged or worn out, they may need to be replaced. Check the jets to see if they are cracked or broken and replace them as necessary.

If you are unable to diagnose and repair the issue yourself, it may be best to contact a professional pool or hot tub technician who can help you identify the root cause of the problem and provide a solution

Not normal for that to happen but the jet faces on the two back jets may be turned off or down.
Try turning the face of the jet clockwise and see if you get more water flow out of each jet.

Rod
US Parts Center

on cool motor, remove fuel line to throttle body, turn switch to accessory position fuel should flow freely. no flow check filter located on frame rail. or defective fuel pump. pressure should be(if checked with good guage)45-55 psi. if all checks out throttle body jet clogged with gunk or you have broken-damaged throttle body wires. all of this i have found on 2.8 liter engines.-------jawstech goodluck hope this helps.

Obstruction to fuel flow is a popular cause of this symptom. The metering passages in the carburetor are very small and it does not take much to clog or partially block them. Depending on how comfortable you feel doing the repair yourself you will need to remove the carburetor to clean the main metering jet as well as the idle jet circuit. The main jet is accessible once you remove the float bowl and the idle circuit is generally accessible by removing a phillips head screw located on the top side of the carburetor. This can vary depending on the specific Honda engine you may have. Also be sure you have fuel flow to the carburetor, if the tank vent in the cap is not working properly you can lose fuel flow to the carburetor. Hope this gets you in the right direction.

You can try driving the bike after the install. After you change the exhaust it will run lean. You may want to coat the inside of the mufflers with an anti blu-ing agent or your headers will discolor. If when test driving you notice the bike has developed a flat spot in the acceleration curve you will want to re-jet the carburetors. The easiest way is to buy a jet kit from Cobra, Dyna-jet,etc.($80-$100). Other wise you can just buy several sets of larger jets and change them out till you are happy with the way it runs. Most people that change the mufflers and put in a jet kit, also install a K&N air filter .
More air flow + fuel flow = more exhaust flow (more power)

Remove your filter cartridge and test again. If flow is still low, then check for debris plugging the inlet to the pump. If removing the cartridge resolves the flow issue, then clean the filter or replace it.

pull carb and clean jets

the outer ring on the out side will unscrew, just be gentle and you may have to use a large pair of channel locks, plyers, but don't grip the plastic to hard so you don't scar the plastic

The breather tube may warrant re-jetting but not re-syncing.

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The excess fuel is caused by the float levels being out of adjustment. Fix the floats and the dead spot may disappear. If not, pull the slides and then move the jet needle clip down one notch. With due respect, I would put the bike carbs back to stock. :)