How to tell if carbs are calibrated

[recman25]

  Just bought a 1999 Valkyrie interstate. The bike runs great, but how do i know if carbs are calibrated with each other. Not trying to fix something thats not broke. Just looking for what to look for.

[gordonv]

You can do a search on digi sync. There are quite a few posts.

Most can't tell there is any problem, but after synchronizing their carbs, the feel is that there bike runs better after.

As for your question, there really isn't anyway of knowing other than testing.

[Cracker Jack]

I assume when you say "calibrated with each other", you mean in sync.

If engine idles smooth with even firing of cylinders, all is good.

The ONLY reason to sync is if the above is not true. My Interstates have never been synced since new and show no signs of needing a sync. If the sync is reasonably close, no real improvement will be realized at operating speed.

About the only time it will be needed is if the linkage has been messed with as with such as a carb remove and replace or if someone has been fooling with it that didn't know what they were doing.

If you do a little searching, you will find stories of improved power and even gas mileage especially if synced with a Digisync (That's the magic bullet). Take those stories with a grain of salt.

[JimmyG]

I've got a 99 also and have wondered the same thing because I have always felt that she hesitates when I crank the throttle at higher speeds. Kinda like bogs down just a little, then slowly accelerates.  ???

[Gryphon Rider]

I assume when you say "calibrated with each other", you mean in sync.

If engine idles smooth with even firing of cylinders, all is good.

The ONLY reason to sync is if the above is not true. My Interstates have never been synced since new and show no signs of needing a sync. If the sync is reasonably close, no real improvement will be realized at operating speed.

About the only time it will be needed is if the linkage has been messed with as with such as a carb remove and replace or if someone has been fooling with it that didn't know what they were doing.

If you do a little searching, you will find stories of improved power and even gas mileage especially if synced with a Digisync (That's the magic bullet). Take those stories with a grain of salt.

Says the person who has never had his 18-year-old (or so) motorcycles synced since new and would not necessarily notice a gradual decline in smoothness or performance.  I think the salt may be more effective sprinkled elsewhere.

That being said, last year I synced the carbs on my 2000 Tourer for the first time, and found the carbs were not noticeably out of sync at the beginning, with maybe a maximum spread of three units (I forget what the units were, inches of mercury, maybe?) from the lowest to the highest.  I didn't notice a difference afterward, when they were all within 1 or 2 units of each other.

[JimC]

Shortly after getting my Valk I did a DeSmog, and at the same time we did a carb sync.

At that time I was told by Darryl (XF6) that one way to check the sync was to place the bike in high gear and slowly roll on the throttle from about 25 mph. If the sync was off, he said you would feel some hesitancy or a slight miss.

I don't know how bad the carbs would have to be out of sync to feel it though.

Jim

[WintrSol]

When I bought my Tourer, the PO said he had recently done the sync, using the two gauge method in the manual, so I didn't check them then (too much hassle, mostly). A few years later, I got a DigiSync, and found they were all pretty close (four counts was the largest deviation), but tweaked them to have the same numbers, with the last digit flipping occasionally. The differences were very subtle, and I wouldn't have noticed any at all if I hadn't gotten to know the bike before the sync.

@recman25: if you are near enough to St. Louis, MO, we can meet and I'll check/set your sync.

[recman25]

@recman25: if you are near enough to St. Louis, MO, we can meet and I'll check/set your sync.

  Thanks for the offer, "Unfortunately" I'm in Tucson Az.
These replies are very interesting. I saw the DigiSync video. That looks promising, but for now I think I'll stick tp the old proverb that if it aint broke, don't fix it

[da prez]

Normal use and wear will cause some variation in the carbs. I have and use a digisync. When I do a de  smog , the carbs get checked. The improvement may be suttle ,  but like all machines , they need to be maintained. Six carbs and throttle cables do need to be working together.

                     da prez

[Hook#3287]

The DigiSync makes the job very easy. Thanks BonS!!

You may get some improvement by doing a sync, or you may not.

If you do one, you'll stop wondering about it.

Maybe someone close by that owns a DigiSync will step up and offer you help.

It'll take all of 10 min to do it.

[97BLKVALK]

@recman25: if you are near enough to St. Louis, MO, we can meet and I'll check/set your sync.

  Thanks for the offer, "Unfortunately" I'm in Tucson Az.
These replies are very interesting. I saw the DigiSync video. That looks promising, but for now I think I'll stick tp the old proverb that if it aint broke, don't fix it

If you wait a little bit the traveling Valk mech BigBF will be heading home to take care of a few things and am sure he would evaluate if needed.  Heres the latest link.

http://www.valkyrieforum.com/bbs/index.php/topic,99548.0.html

[The emperor has no clothes]

@recman25: if you are near enough to St. Louis, MO, we can meet and I'll check/set your sync.

  Thanks for the offer, "Unfortunately" I'm in Tucson Az.
These replies are very interesting. I saw the DigiSync video. That looks promising, but for now I think I'll stick tp the old proverb that if it aint broke, don't fix it

If you get up this way at all, I'd be happy to use my DigiSync on it. 

[recman25]

[/quote]If you get up this way at all, I'd be happy to use my DigiSync on it. 
[/quote]

  Thats real generous, Thanks! I wish it wasnt a 6 hour ride, but yeah if I make it up that way I may take you up on that!

[The emperor has no clothes]

If you get up this way at all, I'd be happy to use my DigiSync on it. 
[/quote]

  Thats real generous, Thanks! I wish it wasnt a 6 hour ride, but yeah if I make it up that way I may take you up on that!
[/quote]We've made a few rides down your way. If another comes up soon I'll pm you. 

[recman25]

Awesome, Thanks!

[Bagger John - #3785]

Before syncing, make sure your vacuum hoses and the intake runner vacuum caps are in good shape (no leaks).

How many miles on the bike, OP?

[recman25]

Before syncing, make sure your vacuum hoses and the intake runner vacuum caps are in good shape (no leaks).

How many miles on the bike, OP?

 Just replaced the intake manifold gaskets. Saw coffee colored stains at the bottom. Hoses are good, and just a over 29k miles

[Chrisj CMA]

If you are replacing the intake o-rings anyway there is a very easy way to physically check the sync.  you need no vacuum gauge or special tools.  Remove all three intakes on the right side.  before replacing them look very carefully at carb #3 (middle one on the right)  On the floor of the intake tube there are three little holes.  The "butterfly valve thinggy closes right on top of the outboard most hole.  Look very closely at how much of the hole is exposed.  Then check the other two on that side.  If there is a noticeable difference fix it to look like #3 with the adjustment screw.  Replace #1 and #5 intakes, leaving #3 open until you check and compare all three on the left side. 

That will get you really close especially if they are far out of whack.

If you aren't going to replace the intake o-rings, you can still use this method however, its more work than actually just doing a carb sync.

[Gavin_Sons]

I've got a 99 also and have wondered the same thing because I have always felt that she hesitates when I crank the throttle at higher speeds. Kinda like bogs down just a little, then slowly accelerates.  ???

could have a clogged jet. Mind did the same. Searched and took everything apart i could think of to find nothing. Then i decided one day to just take the carbs off and took at them. Had 3 main jets clogged. I don't know how it was even running. Looked like rust flakes in the jets but nothing had ever rusted. Put new ones in and it runs great now. I put the sync gauges, now the digisync on mine every year regardless. I know people that have never touched their carbs but i like to make sure mine are perfect.

[Willow]

Not only does the Digisync make it easier to do but you'll not get them synched as closely with any other method.

Synching the carbs gets maximum use and minimum waste.  I picked up a couple of mpgs on average.  I'm sure the power and smoothness is better but I haven't bothered to measure. 

[old2soon]

Not only does the Digisync make it easier to do but you'll not get them synched as closely with any other method.

Synching the carbs gets maximum use and minimum waste.  I picked up a couple of mpgs on average.  I'm sure the power and smoothness is better but I haven't bothered to measure. 

                 Very similar results After the carbs were dygisycned. Consistently in the high 20s to very low 30s on M P G Before digisync. Since having them synced M P Gs are now mid 30s and some of my P G R escorts are flirtin with REAL Close to 40 M P G. And I duz KNOW the butt dyno ain't that close but after digisync there IS a slightly Better performance difference.  RIDE SAFE.

[clanky]

Just to confirm what most people are saying.  I bought the DigiSyn and it's very easy to use. I had to clean the carbs, change floats, tubing, O-rings ect ect.  I notice the most change at idle.  There is absolutely no mirror vibration at all now. My mileage is a bit better.  My two cents worth.