Carburetor sync gauges

[sgwilly]

And no one is going to comment on this tool?

I believe that is a unit that could be mounted on a bike to provide .... oh heck, I read your PDF and I can't even remember what all it said. I just wanted to raise my hand.

I recently upgraded from my fish-tank-air-4way-valve-and-single-vacuum-gauge-hand-built unit to one of the $60 units like this one. You can indeed, calibrate the individual gauges but the covers are a bit of a bear to pry off (leveraging 2 flatheads against each other finally got it done) and the set screw takes a lot of force to move. I'll be using for the first time tonight as a matter of fact. Well, maybe not since I haven't adjusted my valves yet. Tomorrow then!

carbsynch.jpg

[mikenixon]

Look like the ones mentioned at the end of the study. They even have damping valves. Cool. Be curious, I was going to say, now that we know they can be calibrated, if once calibrated they stay the same at higher readings. But, you know what, they don't need to. If they are calibrated at the vacuum level that corresponds to idle on your bike, that's all you need. However, on another bike of a different model, might be they should be calibrated again as their vacuum level might be different at that bike's idle. This might be needed even if you decide to adjust your idle from one rom to another on the same bike. I'm just thinking out loud here, knowing their economy origin.

[sgwilly]

I checked them at 5", 10" and 20" and they looked consistent. This was using a mighty vac with a short hose to each vac gauge independently.

I also have a Unisyn for when my MGB was running. Not exactly precise is how I'd describe it. Of course my Dad used to mock my use of such tools and tell me he'd sync his Austin-Healy Sprite carbs by listening to the end of a hose. Back when Men were Men.

[mikenixon]

[mikenixon]

https://youtu.be/3TkCdvzMReE

This is the link to the video I made in 2012 while with Kawasaki corporate, showing (briefly) the use of the Kowa LCD sync tool. Look for the tool about 2:48 minutes.

[pidjones]

Neat tool. Wonder how it senses/measures the low pressure. Diaphragm? Thermal conductivity?

[mikenixon]

The electronics guys will say something like solid state transducers... I think.

[mikenixon]

I shied away from the gauge- type offerings mostly because they seem cheaply made,

Very smart, I think.

[mikenixon]

I want to comment on this one. I was working on a bike one day back in the 1970s and spotted this behind a sidecover. The instrument was plumbed into the four carbs (a CB550 as I recall) and of course the idea is you open each of the tool's four valves one at a time, and thus you can sync the four carbs using only one gauge. Though I haven't tried it, I'm skeptical of it working. If you have done synchronization you know that during the process the vacuum level is constantly changing. For one thing, as the sync gets closer and closer the idle increases, and that raises the vacuum. And there are other things that make the idle vary as the job is being done. My feeling is this tool should have at least two gauges, so that at all times there is one constant reference.

[Sidecar Bob]

I've never seen one but it looks like it might use a single gauge for multiple cylinders. Or is it perhaps a rig for calibrating sets of gauges?

I still have the Carb Stix too, given to me about 37 years ago by a childhood friend who is a Honda trained mechanic when he replaced them with gauges With only the 2 bikes I don't need them often enough to merit the expense of "upgrading" to something newer when they still work fine.
And mine didn't come with adapters either. When I got them I used an electric drill to drill out a bunch of screws and kept the best 2 of them (the ones where the hole didn't quite come out through the side) for balancing the 2 carbs on the bike I had at the time. They were crude and I'm sure the nuts didn't seal perfectly but it was close enough for me at the time.
When I got the GL1000 there was always something more important to do than try to drill out more screws so I learned to balance the carbs on one side against each other, then balance the ones on the other side against each other and finish by connecting one to a carb on the left and the other to one on the right and balancing the sides.

Some years after I had the '83 I started using the lathe at work for small personal projects after hours so I drilled out 4 new screws with holes that actually came out near the centres, turned their heads to more of a ball shape to fit into the hoses better, soldered the nuts onto them and added o-rings to seal them to the carbs. I also replaced the original hoses (much yellowed and damaged by contact with headers) with ones long enough to make hanging it on the handlebar work nicely.

[mikenixon]

[mikenixon]

I've never seen one but it looks like it might use a single gauge for multiple cylinders. Or is it perhaps a rig for calibrating sets of gauges?

It was meant to be an onboard manometer solution. Too bad it brings inaccuracy to the process.

[5speed]

this is the set I bought. I've only used them once so far so I can't say how good they are.
question Mike.
I used them on a friends 1200 and we could get 3 of the carbs identical but one read a bit lower then the rest. What would cause that? We checked the lines from the intake to the gauge and couldn't find any leaks.
https://www.amazon.ca/gp/product/B01KEO ... UTF8&psc=1

[Sidecar Bob]

Did you switch the one that read lower to a different cylinder to see if that cylinder really was low or the gauge reads low?

[mikenixon]

this is the set I bought. I've only used them once so far so I can't say how good they are.
question Mike.
I used them on a friends 1200 and we could get 3 of the carbs identical but one read a bit lower then the rest. What would cause that? We checked the lines from the intake to the gauge and couldn't find any leaks.
https://www.amazon.ca/gp/product/B01KEO ... UTF8&psc=1

I can't tell from your question if you put each gauge on a carb and were actually syncing, or if you fed all four to one carb and were calibrating the tools. If syncing, what happened when you used the adjuster to alter the pair of carbs that included the one low-reading carb? If calibrating, what happened when you turned the low gauge's calibrating screw?

The guages in the link appear to be the ones that everyone is saying have calibration screws and at the same time are the lowest cost ones avaialable.