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You don't even need to buy a gauge set. Get a few feet of clear vinyl tubing of whatever size will fit the test port nipples. Put some heavy motor or gear oil in it, so when you hold the two ends up the oil sits more or less halfway up the hanging tube. Connect the ends of the tube to the test ports so the tube hangs down. Start the engine and adjust the sync screw until the oil is even from side to side, just as it was before you started the engine. Be aware the oil will surge back and forth, because the vacuum in the intake manifolds is very pulsatile. You are going for an average. You use heavy oil because it isn't as "jumpy" as water or thin oil, and because if the carbs are badly synched the oil won't damage anything if it gets sucked in.
 

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whatever size will fit the test port nipples.
Are our port nipples 6mm? (geez why does that sound bad:D) A lot of gauges come standard with 5mm and say you need 6mm for most Yamahas.
 

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by a set of gauges and do it yourself...ebay about $40

I you are having someone else do it, it shouldnt be more than an hours labor
And at 1 hour's labor, they're charging you for the 50 minutes they didn't need.

I definitely second the motion to do it yourself. Of all the things you could do for yourself on a vstar, this is among the easiest of all. It's not much more difficult than putting gas in the tank, and you can do that, right? Basically you pull two rubber plugs off the vacuum ports, attach the tubes, start the bike, and adjust the synch nut until the oil is even...

This video shows the kind of 'sync tool' I have, and a pretty good rundown of the process.

Many other vids on youtube of the same. Try searching for your bike specifically, you may well find one showing it for your ride exactly.

Just needs tubing as mentioned above + a yardstick & some clear tape. Works like a charm. Only trick is, as others have said, use a heavier weight oil and make sure you have a sufficient quantity (e.g. have 18" or more in the tube) to 'buffer' the oscillation.

7mm wrench, IIRC to adjust the balance nut.

So, well under $10 and you're all set. Takes maybe 15 minutes at most to do the job... Probably takes me 5 minutes these days.
 

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I too have used the above method with excellent results.

I keep my "Rig" in the shop for future uses.
one thing not mentioned here is to ride the bike until warm before doing the adjustment.
The sync will change slightly from cold to fully warmed up.
On my bike (650) I installed several short pieces of the tubing on the ports and about 8" long. I then plugged them and tied them off under
the tank. Rode for about 30 minutes came back to the house and connected the tester I made to the plugged hose ends and proceeded
to run the test. Very slight adjustments are required here.
To much in either direction will dramatically change the reading between tubes. And yes you want an equal level between the two hoses. When done let the bike cool and remove the test hoses and reinstall the caps on the ports. Done. Ride like you stole it... :rolleyes:
 

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So tell me this folks. How much do you guys sync your carbs? This is my 1st dual carb bike. Do you sync every year? Every x miles? Is this sometime done once every 5 years? What are the guidelines?
 

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Carb sync is portion of what a Tune up would be.

The carbs should be synced or at least checked about once per year.
Also remember the rubber sync caps and intake boots degrade over time and can be the cause of leaks, lean running conditions, backfiring and so on.

So syncing the carbs is dependent on the condition of some important
other items...

But the sync balances the vacuum signal between the 2 cylinders.
 

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If it works as it did on my 250 Ninja, the throttle cable actually controls one carburetor. There is a mechanical linkage from that carb to the other, and the sync screw is on that linkage. Adjusting the carb sync actually adjusts the throttle opening on the second carburetor with the goal of having the two equally open at idle, thus causing each cylinder to produce the same power as the other. All being well, the carburetors will then open equally all through their range, and both cylinders will always produce equal power.
 
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