home made sync gauge

[Yahman]

The setup shown is used just to balance the carbs, not to adjust the (fuel mixture) vacuum level. I do that with something similar to the setup posted by Mr. Bill, except that I don't use an aquarium valve. I hook up the vacuum gauge to one carb at a time and adjust for the highest vacuum. After that I hook up the balance tubes to carbs 1/2 and 3/4 and synch. To synch carbs 1/2 TO carbs 3/4, I pick either 1 or 2 and synch it with either 3 or 4 with just one of the balance tubes. Sorry for the confusion.

Not to start a debate on anything, but if I hooked all 4 tubes together at the bottom and put another connector between the two center tubes, it could be used for both jobs. I've just been to busy to make the mod to it. I know it doesn't seem right and looks like it won't work, but it does. That's why I made it in the first place. I just had to try it, with the idea that it wasn't going to work. The thing is very sensitive to any change between the carbs, it will react to me just touching the screws.

Larry

[CatatonicBug]

I don't really want to start a huge physics debate, but I have issues with the above pictured design. If the pairs of tubes on each side are link (with/without a dampener) you are equalizing the pressure above the fluid.

That was my first thought too... You need to have 4 SEPARATE BUT EQUAL sources for the vacuum to pull on. That's why Fred's example of a bottle of ATF with the hoses dipped into it will work just fine. In Yahman's picture, all you're doing is matching 1 to 2 and 3 to 4.

[81xsproject]

I don't really want to start a huge physics debate, but I have issues with the above pictured design. If the pairs of tubes on each side are link (with/without a dampener) you are equalizing the pressure above the fluid. Each tube in the pair would have the same fluid level. The only adjustment that could be done would be between the left and right pairs of carbs... Maybe I am way off, but I don't think so. The only way I can see this working was if you had an extremely small resticter; So, small that the pressure difference from each line couldn't equalize with it's linked mate fast enough to keep up with the vacuum source. The other issue is that the two pairs are isolated from each other which seems to be would make comparing the left and right pairs sketchy at best. Again, I am really not trying to insult you or anything. I just want don't want to see anyone including Yahman to be synching with something that wasn't going to work properly. And, again, maybe I don't know what the hell I am talking about...I'm also anti-colortune.

[Yahman]

There are many ways to do it, here's what I use. I added some flow restrictors to the ends of the vacuum line like the others have suggested. The clear tubing is 3/8". The green stuff in the tubes is water with food coloring added. It's not too big and it works really good.





Larry

[81xsproject]

I don't recommend the single gauge one linked to above. It is difficult to use because adjustments at any single screw effect all cylinders. I recommend using some vacuum line to connect to the ports and plug those into the clear vinyl tubing. Heat causes the vinyl to get loose and soft. The tubes should go up be secured to something like a board. Line all four tubes up in the same arrangement of the cylinders they are attached to. Labeling them is nice, too. Run them down the board and then with 2 T's and a hose to link the 2 T's together. Fill the secured part of the tubes (should be at least 24") about half way up with ATF. Give it time to settle and fill. Mount the board somewhere handy. Take the bike for a ride to get it nice and warm. Come back, hook it up, and sync. If the pulsing is to extreme, you may want to come up with some sort of restrictors to put inline to dampen the vacuum fluctuation. I use old pilot jets. You may also want to get a fan to point at the engine to prevent overheating. I recommend syncing it at around 1500 RPM.

IMPORTANT!!! Keep an eye on the liquid when you first start the engine. If you see fluid in one or more of the tubes go shooting up the tube towards the top, KILL THE MOTOR. This can happen if they are WAY out of sync or there is a vacuum leak, or a tube comes off the port. If you were to suck enough fluid into a cylinder, it could hydro-lock. So, be aware, take your time, and use your brain.

[fredintoon]

It's a Pascal's vases thing

http://www.xs11.com/forum/showthread.php?t=986
Here ya go

Hi Mr Bill,
there is another way:-
Materials:-
Duck tape.
6-foot length of (say) 2" x 1/2" stick.
Transparent jar.
Four 12-foot lengths of 3/16" clear plastic tubing.
Four flow restrictors (use surplus carb jets or aquarium tube squeezers)
Can of ATF.
Assembly:-
Put ends of tubes into the jar. (jar lid is optional but reduces the risk of spilling, poke holes in it for the tubes and for filling with ATF)
Tape the jar to the bottom of the stick and run the tubes up to the top, tape them top & bottom.
Shove the flow restrictors an inch or so into the open ends of the tubes if you are using old jets or onto the outsides if you are using aquarium clamps.
Keep the riggins upright at all times.
Pour the jar 3/4 full of ATF.
Methodology:-
Remove the 4 vacuum caps from the carb manifolds.
Prop the riggins next to the bike.
Put a tube end on each manifold vacuum tap.
Note which tube goes where.
Start the motor.
You will see ATF being sucked up each tube.
The tube with the highest level is being sucked on the hardest.
Adjust the carbs until the levels are the same.
Notes:-
Accuracy:- As ATF is ~13 times less dense than Mercury the height differential between fluid columns will be 13 times as great and so far easier to see.
Why ATF?:-
ATF is readily available, brightly coloured and won't harm the engine if it gets sucked in.
Drawbacks:-
The riggins is 6 feet tall and full of ATF. Compared to a set of commercial carb sticks or vacuum gauges it has storage and movability issues.

[freak_leg]

Thank you sir!

[CatatonicBug]

That's one way of doing it. You can also do it without a vacuum guage at all, and just 4 long lengths of tubing, filled with ATF, hung from the ceiling. Be sure to use a restrictor valve on each tube so the carbs can't suck the ATF out of the tube.

[Mr.Bill]

http://www.xs11.com/forum/showthread.php?t=986

Here ya go

[freak_leg]

Ok guys I've read here and there about the sync gauge made from fish tank parts. I've been looking for a while (on the down low at work ) But cant find the post that goes into detail on it. Can one of you kind gentlemen walk me threw this or link me to the post? I know I've seen it on here before...