My Homemade Manometer

[BassCliff]

Hi,

I can't tell *for sure* in BassCliff's pictures, but I bet the first picture showing the un-aligned balls is with a BS/CV carb.

Yes, that first picture is with CV carbs. You may be on to something. The difference in balancing could very well be a carb issue or a combination of carb/crossover exhaust.

I try not to think too hard about these things. I just fix it according to the book and it works. But I have also experimented and set up my balance both ways and haven't really noticed a difference.


Thank you for your indulgence,

BassCliff



Thank you for your indulgence,

BassCliff

 

[Steve]

I don't think it has to do with the crossovers. The 550 has crossovers for both the 79 and 80 model years yet the 79 factory manual says to sync straight level across all the balls. In the 80 manual it says to sync 1 and 4 even, and 2 and 3 even, but slightly lower than 1 and 4. The major change in 80 was moving from the VM22 carbs to the BS32 (constant velocity) carbs. It would seem that the carb type is probably the overriding factor and not the exhaust type.

I'll agree with part of that, but not all. :-k

I just checked a couple of vendor's sites, the '79 550 did NOT have a crossover in the exhaust.

I don't think that any of the 4-cylinder bikes with VM carbs had a crossover tube when they left the factory.
30+ years of "previous owners" have left bikes with all manner of systems that carry the fumes.

I tend to agree that the 'unbalanced' carbs are required because of the airbox rather than the exhaust. If you balance the carbs with the airbox fitted as per the handbook and then without the box on the gauges become level ( or more level - is 'leveller' a word...?). And this is for the CV carbs - the VMs are in comparison crude old things that are pretty insensitive.

I have never compared 'balanced' carbs with and without an airbox, but that is rather intriguing. Have you tried the same thing with VM carbs?
I just can't picture why the airbox would make a difference between the carbs and engine, but anything is possible.

In practice I have never found one iota of difference between carbs balanced evenly across all 4 or with the half a ball difference so I just set them all level now.

I agree with that. In my ignorance in the "early years", I simply set them all at the same level. When I learned that Suzuki recommended a different setting, I tried it, but could not tell the difference. Since we really have no idea just how much of a difference "half a ball" is, I will continue to set them rather equally, but if the inner cylinders are just a bit lower, I let it ride and don't bother trying to change them.

.

 

[kcorbin]

I'll agree with part of that, but not all. :-k

I just checked a couple of vendor's sites, the '79 550 did NOT have a crossover in the exhaust.

I don't think that any of the 4-cylinder bikes with VM carbs had a crossover tube when they left the factory.
30+ years of "previous owners" have left bikes with all manner of systems that carry the fumes.

.

Actually, if you look at the 'L' model for '79 it does have a crossover tube (yes, 'E' does not) but there is no change in the manual for syncing the 'L' compared to the 'E'. But then, the 'L' also got an integrated regulator/rectifier so it must have had all the 'fancy' upgrades!

 

[kcorbin]

It took me a while, but I finally got around to splicing and posting a video of the manometer in operation with a detailed explanation.

You can check it out here: http://www.youtube.com/watch?v=GaTRyHxvneY&feature=youtu.be

Cheers!

 

[Steve]

WOW.

HOLY COW!

What else can I say? :-k

How FAST was the engine running while you were doing the second half of that video?

Sounds like it was doing about 2500-3000 rpm (or more).

Try it again, but somewhat closer to the factory-recommended speed of 1500-2000 or where most of us actually do it, about 1100, right at idle speed.

The sync has the greatest effect right at idle speed, that is where it should be checked.

Hope it works out for you, but that is far too long running the engine for a carb sync in my book.

Also, never saw how much time and or effort was necessary to get liquid back into that empty bottle.

Still not sure that is accurate, but lilke you said at the end "will have to check this against a Carbtune or other gauge".

Thanks, I'll stick to my mercury sticks and get a Carbtune if they ever fail.

.

 

[Adler]

Actually, if you look at the 'L' model for '79 it does have a crossover tube (yes, 'E' does not) but there is no change in the manual for syncing the 'L' compared to the 'E'. But then, the 'L' also got an integrated regulator/rectifier so it must have had all the 'fancy' upgrades!

Way late to respond to this but my 79' L does not have a crossover.

 

[Guest]

Last year I built a manometer based on your model, but I haven't yet used it. Thanks for the video.

 

[midwestgs]

Just Sync'd the carbs on my 1100G from this design and wanted to add a couple of tips for any first-timers out there.

- I Purchased VOSS water bottles from Walmart. They were about $2.50 per bottle, but I ended up with a real tall bottle & 1 1/2" rubber stopper which was perfect.
- Spent $10 for 5mm brass adapters rather than "drilling & glueing". If you do this- throw the o-ring and use the factory washer.
- Used 3/16 inside diameter tubing which fit the brass adapters, gave a very smooth and even vacuum, no surging or splashing.
- When you get it set, let it idle for a few minutes, I got mine to stay almost even between all four after it was all over.

***- I do recommend a small design change: adding a(four total) fitting(splice) on the carb side (4ft vac hose) would allow you to even out the bottles by blowing into the full bottle, without removing the line from the carb adapter. Not a big deal- however, it would save time not having to reach around to the opposite side carbs. Also, you wont risk bending or breaking you're brass adapter! :encouragement:

Overall, I think it is a great design and worked very well for me. Bike idles much better, starts better and much crisper throttle response.
No doubt there are better ways to sync, but not on my budget. THANKS!