340 Main?

[SammyP]

I have Carbs that have 340 mains in them and I have stock carb but I don't know which to use for my motor.

 

My engine is bored .06 over and has vforce 3 reeds with a boost bootle. I don't have an exhaust yet so I am looking to see which carb to use and depending on that what exhaust to get.

[oldskool]

You have stock carbs and another set? what size?  Stock pipes?  340's are too big for a basically stock motor

[tfaith08]

For that application, I'd use the stock carbs.

 

Take your boost bottle and destroy it.  It has never shown any gain on any dyno in any application that I've ever found.  All it is is a piece of junk that can contribute to an airleak = new top end/complete rebuild almost immediately.  It was marketed because some of the aftermarket companies that deal in the automotive industry sell spacer plates that increase plenum volume.  It supposedly maintains laminar flow into the manifold and engine, but that isn't the case.  It keeps flow into the manifold constant and provides a more accurate reading for MAP sensors and can reduce the likelihood of an intake runner being short-charged.  For a Banshee, this is infinitesimal.  There are more negatives than there are theoretical gains. Get a stock crossover tube. 

 

Since the mains are interchangeable, get some in the sizes of 200-330 for both your current application and future upgrades.  Accept nothing less than genuine Mikuni jets.  I have no clue what stock jetting is since I've never had anything less than T5s and PD Pro Flow and UNI. 

 

Choose exhaust based on riding style.  At near sea level with T5s and Pro Flow w/ UNI, I was running 280s.  Without the airbox lid, I'm at 320 (about to jump to 330 to be safe).