Cheap to make Sync tool for carbs...

[Kreylyn]

I had mentioned this a while back in this thread.

http://katriders.com/vb/showthread.php?t=91752

I finaly remembered to take the camera to the shop and actually take pics of it.



2 bottles
2 stoppers
some clear tubing

Drill 2 holes in the top of each stopper. Cut 1 section of tubing that will run to the bottom of each bottle (about 8-10") and feed it through each stopper. Cut 2 more sections of hose much longer (3-5 feet) and just insert each into a stopper, stopping flush with the bottom side of the stopper.

How it works:

If pressure is equalized in each bottle, the levels of liquid will balance out and be the same in both bottles. If pressure is higher in one bottle, it will push the liquid into the other causing the levels to be different. Its very accurate, but not super fast. Go slow, and give it a moment to balance.

Works like a charm, and is a very small investment (less than $5 not counting the cappuccinos ) if you do not have access to a pro sync tool.

Krey

[jday240]

Neat idea.

[Black_peter]

I gotta ask..

Why not just use the single tube method? Especially since you are only balancing two carbs at a time?

[Kreylyn]

I gotta ask..

Why not just use the single tube method? Especially since you are only balancing two carbs at a time?

I'm not sure I understand your question, so you might need to elaborate if I got it wrong.

The 2 long tubes are used to plug onto each of the 2 carbs your syncing, 1 tube per carb. This way each bottle has the "pressure" of the carb it's plugged up to. The process to sync them would be to equalize that pressure between the 2.

I don't understand how you would get the same effect with only one tube. Please share...

Krey

[Black_peter]

Sure,
First off there is nothing functionally or theoretically wrong with your system.
As an engineer (using vacuum systems every day) it is my job to find flaws in a system and try and correct them

Second off for those who wonder:
Mercury is used in sych tools because it is the densest liquid. So it requires the most vacuum to suck it up a tube. That keeps the tube short. If you used water your sych tool would have to be about 32 feet long.
Next is the fact that you are not setting your carbs to pull a certain vacuum level, only making sure they all pull the same level.

Now to the one tube method. A long tube (only long enough to hang right) with a small amount (10 cc ?) of colored liquid (tranny fluid or something) connected to two carbs then hung so that a loop with the fluid at the bottom will tell you if the carbs are pulling equally. If one is pulling more the fluid will rise up one side of the loop and vise versa. Get the fluid to sit evenly (it will "shimmy" side to side as the carbs are pulling at different times) and the carbs are equal. Most people tape the tube loop to a yard stick. I don't know why as you don't need the marks. But it is handy to tape the loop so that it is easier to handle and keeping the loop fairly even make sure the gravitational pull is equal.

With any home made tester use a fluid that won't damage the bike if it got sucked in (mercury will) and is non flammable.

As I said your system is OK and if you spent say, $25 on it it would be really good. I just worry about leaks, more connections the more chances for leaks. But since we are talking very low vacuum levels I'm nit picking.

[Kreylyn]

ahha... I now see what your talking about now.

My one concern would be there is little time before your going to get the fluid to the carbs one side or the other unless you start out with them very closely synced already. I learned that even with tranny fluid, there is still enough pressure to move it quick...

Speaking of which, be sure to not put more than 40% of one bottles worth of liquid total in both bottles. More than that, and you will start sucking it up into the tubes on this setup.

I'll have to remember the one tube aspect just incase I need something quick one day.

Krey

[Black_peter]

ahha... I now see what your talking about now.

My one concern would be there is little time before your going to get the fluid to the carbs one side or the other unless you start out with them very closely synced already.

Fair point.. I did have a carb that was way out of whack once!
Like 50% more then the other 3

[Kreylyn]

Fair point.. I did have a carb that was way out of whack once!
Like 50% more then the other 3

Wait!... I think the answer to that issue just hit me as well.

1 tube, but dont' use fluid. Use a small plastic ball inside the tube larger than the ports on the carbs. It can't enter them that way, and would be free to move about. If you size it right... that would be a great option. Easier to store as well, and no mess...

Hrm.. think I'm gonna check into that. I'm sure I can find something at a toy store that would work perfect.

Krey

[shibby]

Hi, I'm looking forward too se if the plastic ball tube works=) But i have question, when i am to sync the carbs, i use screws between the carbs and not the air/fuel mix right? so i adjust the amount of opening the carb has?

[Black_peter]

Yes Shibby.. You're basically making sure the butterfly plates are all in "synch", however differences in the valves, pistons, intakes etc, etc means you have to adjust it by flow.

[lmj001]

?

as fore the plastic balls try some airsoft bb,s should fit the hose and if you use a nipple at the carbs it should stay after your done

[shibby]

Great, tanx=) i've changed two of the valve shims so its in need of a sync =)

[quik89Kat]

I bought a motion pro sync tool But before that I had the same setup and I used 2 stroke oil ....that way if it got sucked up it wouldnt hurt any thing ...with that setup and with that fluid level you should not have to worry about sucking anything up it will never reach the upper tubes ....I have a few extra vacuum line restrictors that came with my sync pro if anyone needs them ...

[waffenampt]

So usually a carb sync tool will have 4 hoses. With this setup your testing 2 carbs at one time then moving on to the next two? So with this system your testing carbs 3 and 4 , then moving to 1 and 2 then finally carbs 2-3 for the final adjustment? is this correct since there is only two tubes?

[Kreylyn]

So usually a carb sync tool will have 4 hoses. With this setup your testing 2 carbs at one time then moving on to the next two? So with this system your testing carbs 3 and 4 , then moving to 1 and 2 then finally carbs 2-3 for the final adjustment? is this correct since there is only two tubes?

Pretty close, yes...

3-4
1-2
1-3....

Krey