vacuum synching 930's

where do you hook up the gauges on the carb to synch? must both carbs be synched simultaneously or can you do them one at a time? do regular automotive style gauges work? thanx, rick

There should be two pipes metal pipes(one on each) inlet manifold. Take off the connecting link pipe and use these if you are using a car type balancer. I use a Morgan carbtune type balancer.

Alternatively, you can balance them manually. See link below for advice.

http://www.jba.bc.ca/Bushmans%20Carb%20 ... ml#SYNCHRO

thanks reggie. the carbtune is a little pricey but i guess if i'm going to keep the 930's i ought to get one. the bushman link is a good one. after cleaning the pilots and using bushmans advice i got them down to 600 but it died when i went to put on my helmet. now i'm back up to 800-900. i'm sure the slides aren't what they were and i can live w/800-900 if it'll just stay there. i also need to replace the o rings on the adjusting screws. i've a feeling they're leaking as there's not much resistance to turning them.

Here's another link to a previous discussion on the carbtune.

use-carbtune-t2511.html?hilit=morgan carb tune

One method I've heard of is very simple and cheap. I tried it and it worked. You get about 7-8ft of clear gas line, make a loop between the spigots on the intake manifolds that points down . You put enough oil in the line to achieve a height of around a foot at the bottom of the loop. When you start the engine you can see the oil pulse from one side to the other. It was not enough to make it bubble but you could easily see which side was winning or pulling more vacuum from the difference in the heights in the columns of oil. It is ridiculously simple.

I have a Twin Max left over from my BMW oilhead days and have used it on the Norton, it is comparable to the CarbTune in price, but has a transducer that reacts to any difference in vacuum between two cylinders, very dependable, very accurate.

BUT

Using the proceedure described on Bushman's website I get perfect results and I can do it with the engine not running and not have to be concerned with the effect of heat build up. I have done the sync both ways, checking each with the other and find no differences.

Interested in a used Twin Max?

RS