Balancing twin carbs

If you have an assistant, here is one way. Press the forefinger of each hand against the throttle stop screws. Have your assistant open and close the throttle. You will feel which slide closes first and then make adjustments until they both close together.

Previously wrote:

seem to remember,two straight rods (short length of welding rod)one in each carb view from side and adjust till rods level,,makes sense to me ,unless someone knowes better

This is a good method when you've access to the intake of the carb. There's no way to do this with the standard black plastic airbox fitted.

If it is MKIII, remove the rubber bellows and stand on right hand side of bike, left hand fingers in the carb inlets touching the slides, the right hand on the throttle. Slowly operate the throttle and you should feel slides start to lift at the same time. when the first slide is full bore, feel to ensure that the other is also clear, then check the same on the other slide. When on the throttle stops (lowered) it does not matter if one slide looks a little higher than the other.

If it ticks over fine and both slides move together and clear full bore at the same moment, you are pretty much there. There are gauges that can help, but this much Krypton tuning a tractor. A good road test at speed gently opening and closing the throttle to to see how it picks up will also give good indication of the mixture settings.

And yes the rubber bellows are pig to put back on - use some silicone grease or spray in the seating grooves.

The best way I have found to balance carbs on any bike with more than one cylinder is to use balance gauges. I've used Morgan Carbtune but prefer vacuum gauges. Takes all the guessing out of tuning your carbs, and once you know the slides are synchronised then you can start to adjust for tickover and pickup off tickover. Make sure your carb bodies and slideshave virtually no wear otherwise the engine will run weak at tickover and small throttle openings resulting in erratic tickover and slow running. I've had my Amals bored to remove wear and the slides sleeved in brass to .001'' clearance and the carbs are now reliable even with 10,000 miles use and should be good for many more.

Simon.

I can endorse what Simon says about either a pair of dial type vacuum gauges or the "morgan carbtune" and you won't need access to the front of your intakes to see what is going on. Consider the four cylinder "carbtune" and charge your mates a fiver to balance their rice burner's carbs for them. Soon cover the cost.

As a first step. it's easy to get the throttle slides synchronised by ear. Listen carefully and you can hear them click on closing. Hear two clicks and they are not closing together.

In simple terms;

1. remove the rubber gaiters between carb and black box.

2. unscrew the idle screws so they dont touch the slides.

3.Check the junction block under the tank and ensure cables are seated properly.

4.take two lolly sticks and feed them into the carb mouth under the slide cut out. You can do this with the black box !

5.Twist throttle and decide which one needs adjustment, dont fiddle with both cable adjusters. One is either early or late !

6. turn in idle screw in until they just touch the slide. Put finger on head of screw and twist/lower throttle, you will feel it hit.

7. REMOVE lolly sticks ! Start it up and once warm hold it on throttle, and adjust idle screws in EXACTLY same amount to get even tickover.

(THIS IS PRESUMING YOU HAVE THE MIXTURE ADJUSTED CORRECTLY) Bon chance.........