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Synching carbs

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cbdinak

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"YET ANOTHER QUESTION, EXACTLY

"YET ANOTHER QUESTION, EXACTLY HOW IMPORTANT IS IT TO SYNCH YOUR CARBS? I AM RUNNING TWIN AQ 140S, OBVIOUSLY WITH DUAL SIDE DRAFT CARBS.
HOW WILL IT EFFECT IDELING, AND THROUGHOUT THE REST OF THE OPERATING RANGE?"
 
Its marginally more important

Its marginally more important than not typing in caps. Its like yelling at someone on the internet.....:0) Its good to get them as synched as possible. There is a device called a Uniflow something or other. Do a search uless someone else mentions it first
 
"JC Whitney used to sell an in

"JC Whitney used to sell an inexpensive 4 port sync device in the motorcyle section. It's works on the vacuum principle. gives you a vacuum reading on each carb. Each tube is port into the same vacuum port just below the throttle plate of each carb,Idle screw (Throttle stop) is adjusted on each carb to equalize the vacuum below the Throttle plate of each carb. (Note: ensure all throttle plates are closing fully and are not being held partly open linkage bind prior to ajustmet, also individual Choke plates/linkage, if present must be syncronized prior to adjustment as that to can affect the sync on the carbs)"
 
"Becuase this is a twin engine

"Becuase this is a twin engine setup and not a multi carb on on engine, ensure idle RPM remains equal and constant on each engine prior to and during the adjustment. It's also a good idea to ensure intial timing and the vacuum and/or centrifical advance (Spark curve)is equal in both engines prior to syncing carb. if you need help in checking spark curve, this is done easily with a timing light and paper and pencil. let me know and i can explain the procedure."
 
"Ofcourse,it almost goes witho

"Ofcourse,it almost goes without saying that the throttle linkage/cable setup must be adjusted up w/o any slop or delay of throttle. (there, I said it!) anything like that could affect sync. The idea here is same exact setup on both engines. both engines rev up from idle to WOT in perfect syncronicity like "ONE" big engine! Watching both Tachs during slow revs is a great way to check your work! It helps it the Jetting( IE Richness Setting) on each engine are close to the same too as one motor lean and one motor rich will start off equal (after Syncing) but will increase RPM at different rates and say at 3/4 throttle Eng. A will be at say 3950 RPM and Eng B will be at 4000 RPM. This is NG. Alot of info, I know but alot can affect sync. And that is assuming one of the engines doesn't have a vacuum leak, poorly sealing rings ect. Hopefully a Vacuum gauge/ sync device is steady and not bouncy or low/erratic @ idle on both engines-This is a good sign that all is well in both engines!"
 
"Sorry, I just realized this i

"Sorry, I just realized this is a multi engine with multi carbs! Works basically the same but you are syncing both carbs together on each engine while syncing both engines with each other. you'll still end up witl all (four) carbs pulling the same amount of vacuum pretty evenly. This set up will make it even more critical that the jetting on ALL FOUR carbs be equal so all cylinders of both engines see the same fuel/air ratio and thus make an equal and even amount of power. a balance test might be a good idea to help to check cyl. to cyl. weakness."
 
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