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Fuel & Carb & Exhaust

This is a decent exploded view of all of the parts of a CV carb:


This explains CV carbs inside and out with text and photos: Jetting and Understanding Your CV Carburetor (pdf)


There's three views of a CV carb in action here. The top is the carb at rest, the bottom left at idle, and the bottom right under throttle. You can see how the vacuum develops and lifts the needle up allowing more gas into the mixture:


Adding Carb Jets (video)


Carb cleaning (video)


This diagram of an auto choke is quite accurate yet simplistic. The following was sent in to Scoot Dawg Forum by Gary2gs in response to my repeated attempts to conceptualize how this device worked. The fuel enrichment pathway in the carb is open when you start your scoot. When the device heats up in about five minutes, the plunger slides out, and shuts OFF the extra fuel pathway. Thanks Gary:

Enricher Diagram


This is the actual technical diagram of an autochoke:

Auto Choke


Next is a diagram of the PAIR emissions system. It stands for Pulsed Air Injection Reburn. It sends pulses of fresh air into the exhaust during low pressure pulses in the exhaust side. This is a canister that has a vacuum line and a hose to the valve cover area. It is usually only on newer scooters. This helps burn uncombusted gases that make it through the engine. Earlwb, a font of knowledge, sent this to me. Thanks again Earl:

Exhaust Emissions System


Another canister may be hooked up to your scooter, this is the Vapor Recovery System. Usually you have either this or the PAIR, or neither; aren't scooters fun?! A PDF from Earl ( thanks again ), Vapor Recovery PDF and a diagram from Owenbrau ( much appreciated), follow:

Vapor Recovery System


This is a picture of the vapor canister for the Vapor Recovery System, it's location may vary:

Vapor Canister