Carb syncing using light

I had my carbs of my XJ550 to do a cleaning and rebuild. As I was putting everything back together, I got the idea of using light to sync the carbs. What I did was to first shine a light through from the air cleaner side of the carb with the idle adjustment. I then adjusted the idle screw so that the light shining through the bottom of the throttle valve just disappeared. I then moved to the carb next to it, turned the sync adjuster until I could see light then backed it off until the light just disappeared. I then did all the remaining carbs the same way.

I know that this doesn't address any leaks in the intake that the gauges would compensate for and I know that the final check should be done that way but using light allowed for what seemed like a very precise adjustment of each carb and will certainly get you in the ball park especially if everything is tight on the intake boots.

Just thought I'd pass that tip on.

Happy Trails!
sanoke

 

This seems to be a variation of bench syncing, which is recommended by the experts that post here.

There is an excellent tutorial with pictures here:

http://xjbikes.com/Forums/viewtopic/t=6 ... bench.html

There is a second method using strips of business cards instead of paper clips posted by RickCoMatic:

http://xjbikes.com/Forums/viewtopic/t=6 ... +sync.html

Rick's method works better for me. The paper clips seem to leave the butterflies open a bit too much.

The final check should be holding the carbs to a light and making sure all the butterflies appear to be set the same.

 

That was my understanding as to how it was done. My question is, how is this done with the carbs on the bike? Take all the vacuum caps off and try to look down the little hole?

 

For the record, another option that I found was just the right size for syncing the carbs is the metal wire that lives inside those flat plastic ties that are used for tieing off the plastic wrapper on a loaf of bread or the like.

Take the metal strip out and have the butterfly valve adjusted so that the metal strip just fits through with a hint of resistance. I saw this somewhere on someone's site - if I find it again I'll post - had pictures etc of all the steps.

That would be a good bench syncing starting point.

 

I found the paper-clip too large also. I used regular printer paper-2 layers thick, 3 inch long and 1/4 inch wide, shut the door on #3 until it drags the paper, and match that same drag feel on the other 3 butterflies.
I built a 4 tube " manometer " and the sync was only about 12 inches off. It was so cool seeing red dyed water jumping to the beat of the engine. And being able to see all 4 move to the slightest turn of the screw.

This'll be alot easier--search" $5 carb sync tool " from way back in April.

 

the only problem with using water is if you accidentally suck some into the engine

 

true, we wouldn't want that, but the filters would be filling with the red water--or oil, if you prefer, if it were way off and the bottom of my set-up only has about an ounce [27 ML] and I didn't want a lengthly post, so if you are careful, it won't happen.

It seems the post "have to use instant start" has the same idea with Hired_Goon contributing as well in what they call a nanometer. It's the comparative difference of vacuum between the 4 intakes. Also the idea of getting a kit in the mail with a Colortune and a version of carb sticks and instructions would be great!! And Chacal is right saying that we are tuning our carbs before getting the valve shims right!!

"how can you have any pudding if you don't eat your meat!"

 

We dont need no education
We dont need no thought control

 

I think it's actually called a manometer. A nanometer is an extremely small unit of measurement (one billionth of a meter)...or a device used to calibrate iPods