Hello all…. Put newly rebuilt carbs on the bike this afternoon… been trying to balance them… the far right is about 10 the others are about 7 on the gauge.. can’t seem to lower the right one.. I think you can’t adjust that one.. can’t get my head round it.. do I set the other 3 carbs to 10. tick over is about 1500 any advise would be great. Thankyou.
When carbs are off the bike, it’s best to do a “bench balance” as best you can. Adjust all the throttle plates to the same opening before fitting them to the engine. Firstly I set all the pilot screws to 2 turns out fron lightly seated…I then use a piece of 0.020” lockwire and adjust the throttle plates all to the same opening starting with #4 using the idle screw, then #2, #3 and so on. This will get you in the ballpark. Then fit the carbs to the engine.
Far right cyl is #4….#4 is the “Master”, the throttle cables and idle adjustment screw acts on the #4 Carburettor, all the others are adjusted in sequence to match it. In order it’s #4 (using the idle screw), #2, #3 and finally #1.
There is an art to it…and be patient. Make small adjustments as adjusting one will alter the others in sequence down the line. If the idle increases/decreases, adjust the idle screw to bring it as close to ~1000rpm as possible and continue. The adjustment screws are a pig of a thing to get at unless you have the 90 degree adjustment tool like this one:
In the pic below, with the carbs upside-down….#4 is the top left carb, as you can see, the idle adjustment is used on #4 only…. Circled in red are #2 at the top right, the joining link can be seen going to the other two carbs #3 & #1 at the bottom left and right respectively.
Let us know how you get on.
Smithy.
