Syncing carbs

[fjbiker]

Hi Gang,

I have a question about syncing my '84 FJ1100 carbs.
I've synced carbs 1 & 2 together to have the same vacuum reading, then 3 & 4 together to have the same vacuum reading, then adjust pair 1&2 to equal pair 3&4.

In the past, I've just stopped there.
However, last night I noticed that if I continue adjust pair 3&4 to have a higher reading than 1&2, the idle speed starts to increase.

Should I be adjusting so until I can get the highest idle speed, even though the vacuum gauges show that carbs 3&4 are not balanced with 1&2?
Or adjust so all are equal, ignoring the increase of idle speed?

Any thoughts?

BTW, I'm using a carb sync kit with four individual vacuum gauges.

Thanks, Mark

[andyb]

Get all four balanced straight across.  Seems to me that you have to adjust the idle periodically while you do it sometimes.  If you think about it, what you're functionally doing if you intentionally give the center screw a good crank (sounds dirty... isn't... honest) is opening the throttle on half the carbs, so of course the revs will rise, yes?

I personally adjust mine at 3krpm or so (manually turning the idle up, setting the sync screws, then putting the idle back down), because I want as much smoothness right at that cruise RPM range as I can get.  I spend a lot more time at 3k than I do at idle.   

[fjbiker]

Thanks Andy for the great reply. That makes perfect sense what you're saying.

Mark

[Pat Conlon]

Yea, Andy tends to do that...a lot

One caution 'thou, if you have the liquid filled column gauges, be careful about sucking out the liquid...

Don't ask...

[Easterntide]

not a hijack but a question about carb synch tool. my local canadian tire has a single gauge for 25$. can you do a one by one by one by one synch and have it be successful?

[movenon]

not a hijack but a question about carb synch tool. my local canadian tire has a single gauge for 25$. can you do a one by one by one by one synch and have it be successful?

Short answer. No... Takes 2 gauges or tubes to read at the same time, some like to read 4 at the same time. Yamaha's method for the FJ is two at a time.  You can make your own system for less than 15-20.00.
http://www.fjowners.com/index.php?action=gallery;sa=view;id=2479
George

[andyb]

+1

Gotta have two at least.

And in my experience, if you want to get done before you die of old age, you gotta have four.

The right tool is worth the money.  You'll feel like a dork, because you'll go "wtf did i spend all that for?  That was easy!"... it's because you had the right tool.

[JPaganel]

And in my experience, if you want to get done before you die of old age, you gotta have four.

I got done in about 20 minutes last night with my liquid gauge.

[Pat Conlon]

^^^ I hope you mean that did not leave your bike idling for 20 minutes. Much too long.

The quicker you can get the job done....the happier your exhaust valves and valve seats will be..

Unless, of course you have a big box fan (or two) blowing air across the cooling fins.

[JPaganel]

^^^ I hope you mean that did not leave your bike idling for 20 minutes. Much too long.

Nah. Actual adjustments are a minute or two. I counted all the messing about in the garage.

[bcguide]

I have synced my fj using 1 gauge. it takes a while but it can be done