Topic: Carb Sync Gauge Faulty??

[jimbojangles]

I'm not sure where to post this, so apologies if it's the wrong place.

Has anyone had any experience with a faulty carb tune gauge?  I have had the same Emgo dial gauge for 5 or 6 years and I'm starting to think it's part of the cause of years of problems I've had.

I recently purchased a Kawasaki Concours and everything is running pretty good. I just got back from a 2,000 mile or so trip, however I know the idle isn't spot on. I've synced the carbs a dozen times, but can't seem to get it to smooth out.

So here's why I'm thinking it's the gauges:

1. I noticed that gauge 4/cylinder4 didn't rise at the same rate as the others when throttle was applied.
2. I tried switching the vacuum lines around to determine if it was a carb boot vacuum leak or a leak in the vacuum line going to the gauge. It appeared to be the vacuum line, so I went ahead and replaced all the lines since they were several years old and have been used on several bikes.
3. after replacing the lines I noticed that gauge 4/cylinder 4 is still off. For example, lets say all gauges read 5 (pounds?) of vacuum. #4 will read maybe 7 or 8.  I can adjust it to be like the others (in sync) but the idle gets rougher. If I take the line from the #4 cylinder and place it on the #3 gauge it will give a very different reading.
4. As I sat and stewed and drank, I started thinking. I have never been happy with the idle on any of my bikes and I have had trouble with the #4 cylinder on all 3 bikes I've used this gauge on.

So, am I using an inferior gauge that's faulty or am I just grasping at straws to why I can't get a sewing machine smooth idle out of this machine?

[DaveBarbier]

Seems like you should have the gauges all pull from the same vacuum source for calibration. That's an important first step whenever you sync.

http://forums.sohc4.net/index.php?topic=140688.0

[jimbojangles]

I remember when i got the gauges i set them all to read zero before ever using them, but that was just sitting there without a vacuum source connected. I dont have a way to connect all 4 to the same source at the same time, but i'll try connecting them all to the same cylinder one at a time and setting them the same. Its at least worth a try before buying new gauges. Thanks

[DaveBarbier]

Go to your local hardware store and get three tee barb hose fittings for 50¢ a piece and a length of hose and you'll be all set.

Its at least worth a try before buying new gauges.

They're designed to be calibrated. New gauges will have to be calibrated also.

[mrbreeze]

That's why I like my Morgan. One less thing to do (calibrate). If you have to make do with the gauges though....the way you said is what I would do. One at a time on just one carb.

[Deltarider]

Go to your local hardware store and get three tee barb hose fittings for 50¢ a piece and a length of hose and you'll be all set.

If you're suggesting that you can calibrate the set by connecting them to the same cylinder at the same time, I must warn you it won't work.

i'll try connecting them all to the same cylinder one at a time and setting them the same

Correct, one at a time.

[DaveBarbier]

Go to your local hardware store and get three tee barb hose fittings for 50¢ a piece and a length of hose and you'll be all set.

If you're suggesting that you can calibrate the set by connecting them to the same cylinder at the same time, I must warn you it won't work.

Yes, that's what I was saying. Why wouldn't that work? The motion pro set I have says to do it this way and includes a 5 barb fitting with extra hose. Although that's not needle gauges but fluid.

In the above link I posted there's some debate on which way to calibrate. Actually, Delta, you're in that link too .

[DH]

I remember when i got the gauges i set them all to read zero before ever using them, but that was just sitting there without a vacuum source connected. I dont have a way to connect all 4 to the same source at the same time, but i'll try connecting them all to the same cylinder one at a time and setting them the same. Its at least worth a try before buying new gauges. Thanks

That should work. hooking them up individually and one at a time will isolate gauges from one another. use the same vacuum source (cylinder) and hose to test each.

[flybox1]

I remember when i got the gauges i set them all to read zero before ever using them, but that was just sitting there without a vacuum source connected. I dont have a way to connect all 4 to the same source at the same time, but i'll try connecting them all to the same cylinder one at a time and setting them the same. Its at least worth a try before buying new gauges. Thanks

That should work. hooking them up individually and one at a time will isolate gauges from one another. use the same vacuum source (cylinder) and hose to test each.

Setting them to ZERO does nothing. You could set them all to any number.  It would still be incorrect.
You are making the assuming that all gauges are equal, vac lines are all of the same length, ID, and will hold their shape when vacuum is applied, and that it was assembled correctly.
Calibration must be done from one source, and each gauge individually adjusted to that source.
The number on the gauge does not matter, only that they all read the same.

[rotortiller]

Emgo gauges have a calibration screw under the front cover. Use this cheap tool to make the guges read the same before using on the bike.  Cal at the area you expect to sync for the absolute best precision. After you do that should you still have issue swap gauges and restrictors to see if you have the same results. Then you know if your  engine is crap or not.

[jimbojangles]

I honestly appreciate the replies. It's been years since I got these gauges, but if I recall correctly it was the instructions that were included that told me to set the gauges to be equal before ever connecting to a vacuum source. They were all pretty close to 0 so that's what I dialed them in on. There was never anything that said to calibrate with vacuum. I've also been on this board for years and never saw anything about it.

I will re-calibrate tonight with a vacuum source and see what happens. I'm hopeful this is my problem, but also a little depressed that this may have been a cause to my problems for several years.

[flybox1]

I hear you Jim.  I had the same issue with an Actron dwell meter.
They indicated it came calibrated.  The indicator needle was nowhere near zero at rest.
When it was turned on, the dwell reading on the unit for my points were so far off, that if i adjusted the point to the correct dwell reading, the bike would stall out.  There was no way for me to calibrate this unless i found some other points system(properly set) to calibrate it to 
Needless to say I ditched this dwell unit and went back to feeler gauge points settings
Luckily, you have your choice out of 4 carbs to calibrate to 

[Deltarider]

In the above link I posted there's some debate on which way to calibrate. Actually, Delta, you're in that link too .

Correct, with the same warning.

[rotortiller]

Actually if you want to use the hypo individually on gauges using the identical hypo graduation and compare (to doing all 4 gauges from the same hypo manifold) they will yield the same results. I just tried it. More than one way to skin a kat.

rt

[Deltarider]

Just don't connect all 4 to the same working cylinder at the same time.