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Balancing my carbs,

Started by Shane4371, December 05, 2015, 07:41:18 AM

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Shane4371

Seen videos on you tube,however is their a difference between balancing the carbs and syncing them?got advise from friends saying doing it by ear is pretty reliable,noticed 2 carbs use one screw to sync them?and the outter carbs have thier own sync screws?

Arnie

Sync'ing or balancing is the same process just different names, getting all carbs to draw the same manifold vacuum at any given speed.
You can do a mechainical balance on them, but its not nearly as accurate as using a set of vacuum guages.  The commercial ones are not horribly expensive, but you can make a "mannometer" that is just as accurate for $10-15.  Plans are in the files section.

The FJ uses 3 screws for this process on the linkage.  You balance cyl 4-3, then you balance cyl 1-2, then you balance the 4/3 to the 1/2.
You will not get close to balanced by ear.

It really is an easy and quick procedure, and it makes enough difference to vibration and feel that evey time I have my tank off, I re-balance the carbs.  There is rarely much of a change, but the better this balance is, the better the bike feels.


Shane4371

Thanks again Arnie,your a cup.so all I'll need is 3 vacuum guages?

Arnie

No, you could get by with 2 but that makes it difficult cause you have to change the connections back and forth.
There are sets of 4 analog vac guages, some other balancers with mercury, or stainless rods, OR
You can make a 4 cyl manometer with 20ft of vinyl tubing, a bit of ATF and a wooden mounting board.

Actual numbers (in of Hg) are not important.  You only need them to all be the same.

Search and you will find.  Here's one I just did via google:

   http://www.fjowners.com/index.php?topic=6686.0

Have fun :-)

simi_ed

-- RKBA Regards,

Ed
===
Ed Thiele 
Simi Valley, CA -- I no longer have SoCal manners.
'89 FJ12C (Theft deterrent Silver/White)


- All that is necessary for the forces of evil to win in the world is for
enough good men to do nothing.

- Edmund Burke