what is the unit of measure used to sync carbs ? i want to say cm/hg .if so how many?
JROCK
TY 4 Stroke Junkie
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I believe it Is inches of mercury vacuum should be 18-22
Len Todd
TY 4 Stroke God
All you are doing is matching the other three carbs to the base carb. Base carb is # 3 in an RX-1. You do not need to worry about setting all the carbs to a specific setting. It is very helpful to have a 4 tube manometer because all the carbs interact and the mercury is bouncing around to much to get a specific reading. You just want all 4 tubes equal.
Rice_Z24
Veteran
Not to hijack the thread but which carb would be # 1 and/ or #3
Len Todd
TY 4 Stroke God
Good question. The throttle cable is connected to Carb #3. The bolt to adjust #2 is right next to the throttle cable. That makes #1 on the PTO side and #4 on the mag side.
i'm asking because i do not have sync tool specifically for this application.but i work in an instrument shop and have access to both inches of water and inches of mercury . not sure which ones to grab or the range i need . these types of manometers you can suck the liquid out .
Len Todd
TY 4 Stroke God
You need a tool with mercury.
Also, like I said before. It is going to be very hard to sync 4 carbs with one or even 2 tubes. The mercury bounces around a lot and you need to see them all to kind of average them so they are all bouncing at the same level, so to speak.
Also, the tool of choice has some orifices in the tubes. This reduces the likelihood of sucking down the mercury. But, it does not preclude the risk. Mercury in the engine is not good. Also, even with the mercury, you do not rev the engine much at all. Just and occasional blip of the throttle in between adjustments. If you over do it, you will suck the tool dry and maybe even do some engine damage. Can you imagine trying to compress mercury?
You will need a couple tees. The carbs also run the Fuel Pump. With the right manometer, you can do the syncing fairly quickly, before you run out of gas in the carbs. However, if you tee in the manometer, you do not have this time constraint.
Also, like I said before. It is going to be very hard to sync 4 carbs with one or even 2 tubes. The mercury bounces around a lot and you need to see them all to kind of average them so they are all bouncing at the same level, so to speak.
Also, the tool of choice has some orifices in the tubes. This reduces the likelihood of sucking down the mercury. But, it does not preclude the risk. Mercury in the engine is not good. Also, even with the mercury, you do not rev the engine much at all. Just and occasional blip of the throttle in between adjustments. If you over do it, you will suck the tool dry and maybe even do some engine damage. Can you imagine trying to compress mercury?
You will need a couple tees. The carbs also run the Fuel Pump. With the right manometer, you can do the syncing fairly quickly, before you run out of gas in the carbs. However, if you tee in the manometer, you do not have this time constraint.
abj87
Pro
I ended up doing it with a rubber tube stuck one end in my ear and held the other to the carb neck and adjusted the carbs till they sounded the same. I later checked it with a manometer and it was spot on.
