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- Dec 3, 2009
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This thread is a collaboration of many years of information built from member experiences and studying the history of carb tech.
There has been plenty of completely wrong info on what a carb is and does, and what it takes to be one. This makes no difference whether you're talking stock carbs or others as it applies to oldwing motors ...
Carbs have been around for over a hundred years ...a basic carb is a very precise tool for metering the correct amount of air and gas to burn efficiently in an internal combustion engine.
Many have experienced how the stock 4 carb system has degraded to such a point that the bike flounders so bad at low rpm that slow RPM riding becomes an ordeal. With a stock CV carb system, they rely on vacuum to pull the slides up to increase air flow and then gas charge. This is a relatively slow acting process.
Honda provides for sync tuning of carbs so at a certain rpm you can adjust vacuum. This sounds great but does not fix uneven cylinders. As soon as rpm goes away from the synchronized spot it's right back to uneven. This is just a very poor arrangement and is a degradation to decent gas charge in the engines' capable rpm zone. A good carb system will provide a good fuel/air mixture at idle and stay even to top rpm.
Vacuum like a lot of things on engines are not consistent, it is different cold than it is hot like oil is different from cold to hot, so its not a very good thing to build around at all...especially x4 in a stock set up.
Vacuum added to carbs got big in the sixties and was added to two stage carbs as in 4 barrel carbs. They added vacuum to engage the throttle plates to open the back barrels of the carb.
This is when carbs started going into less than a carb territory. It wasn't long before they started making non adjustable carbs making them so owners could not tune or modify them. Oldwing carbs made stock were deep into this user unfriendly induction system, as the years went along it also spread to ignition timing...
These two factors of stock oldwings made many want something better, as well new parts are getting more scarce, and no service by Honda for these bikes..
This has ushered in many who want something simpler and adjustable, and more performance driven..........
There has been plenty of completely wrong info on what a carb is and does, and what it takes to be one. This makes no difference whether you're talking stock carbs or others as it applies to oldwing motors ...
Carbs have been around for over a hundred years ...a basic carb is a very precise tool for metering the correct amount of air and gas to burn efficiently in an internal combustion engine.
Many have experienced how the stock 4 carb system has degraded to such a point that the bike flounders so bad at low rpm that slow RPM riding becomes an ordeal. With a stock CV carb system, they rely on vacuum to pull the slides up to increase air flow and then gas charge. This is a relatively slow acting process.
Honda provides for sync tuning of carbs so at a certain rpm you can adjust vacuum. This sounds great but does not fix uneven cylinders. As soon as rpm goes away from the synchronized spot it's right back to uneven. This is just a very poor arrangement and is a degradation to decent gas charge in the engines' capable rpm zone. A good carb system will provide a good fuel/air mixture at idle and stay even to top rpm.
Vacuum like a lot of things on engines are not consistent, it is different cold than it is hot like oil is different from cold to hot, so its not a very good thing to build around at all...especially x4 in a stock set up.
Vacuum added to carbs got big in the sixties and was added to two stage carbs as in 4 barrel carbs. They added vacuum to engage the throttle plates to open the back barrels of the carb.
This is when carbs started going into less than a carb territory. It wasn't long before they started making non adjustable carbs making them so owners could not tune or modify them. Oldwing carbs made stock were deep into this user unfriendly induction system, as the years went along it also spread to ignition timing...
These two factors of stock oldwings made many want something better, as well new parts are getting more scarce, and no service by Honda for these bikes..
This has ushered in many who want something simpler and adjustable, and more performance driven..........