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using UNI-SYN tool

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I hate to be involved with bursting any bubbles or cherries but I think Andrew is on to something. Others were able to use this tool with success. I keep thinking I'm missing something obvious or using it wrong. The tool came with a "box", though it is just the plastic packaging. I got it a few years back for the TR6, but never needed to use it. It's from V.B.. The centering/adjustable diaphragm is dented, the tube is made of plastic, the hole in the top of the tube cover was drilled and a lot of debris stuck to the end of the hole (possibly blocking it), the graduated tube assembly was attached to the main assembly through a very roughly shaped hole, and held together by a screw through a smashed spring. It says "MOD A CHINA" on the front of the tool.

After taking it apart again and cleaning all the holes thoroughly and cleaning the tube it seems to be working with my 1hp shop vac. I can adjust the center so the indicator is in the center of the tube. What good is a tool that takes a spot on a shelf but can't be used. If it still doesn't work when I use it on the car, I'll throw it away.

Thanks for all the input and patience.
 

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Well, try and work with your mod a China part, but if it's junk, toss it! Geez - mod a China.
 
At least for Strombergs I've had no problem with Unisyn, but likewise its a 30 yr old tool and maybe it was made better 'back in the day'?

I have a fancier air flow gauge sitting in the toolchest that I haven't tried yet - ebay purchase. You're welcome to try it out if you want - and can even grab it if you are coming to the club meeting this Saturday?
 
I've a couple of the 40+ year old ones, both work reliably. I've seen the newer sino made version, it's a tinny, cheezy counterfeit.

:pukeface:
 
I'm late to the party but have used my Unisyn since 1976, never had a problem at all and its been used on a lot of LBC's. Sounds like someone got a defective one.

Marv
 
Having seen Vic Edelbrock Jr. doing commercials on SpeedTv, I get the impression that he really cares about the products he puts his name on. I know he didn't make that Uni-Syn, but he might like to know of it's poor quality.
 
Don,

Sorry, I don't know Mark. I've been much more active with the vintage bike clubs lately than Tyee. But the Norton in the living room sounds interesting.
 
TR4nut said:
You're welcome to try it out if you want - and can even grab it if you are coming to the club meeting this Saturday?
Click to expand...

Cool. First you will show me how well it works on your TR3, right? If I pull the front carb off to properly seat the butterfly, I'll have to adjust it all over again... It should be faster next time since I'm a little less clueless.

Prudence and I will be there and I will definitely bring my UNISYN and compare it to yours, as well as a few loaned parts I need to return.
 
makes me not feel so bad about only using a lenth of hose and my ear.
 
thanks don! I almost choked when I saw this. LMAO.
 
TR4nut said:
At least for Strombergs I've had no problem with Unisyn, but likewise its a 30 yr old tool and maybe it was made better 'back in the day'?

I have a fancier air flow gauge sitting in the toolchest that I haven't tried yet - ebay purchase. You're welcome to try it out if you want - and can even grab it if you are coming to the club meeting this Saturday?
Click to expand...

Randy, thanks for loaning me your old UNI-SYN and your synchrometer/flow meter, knowing I was going to take the UNI-SYN apart.

I am sure the "MOD-A" and "MOD-A CHINA" are different. Forgive me if I'm beating a dead horse, but for future reference I'd like to show what I found and corrected to make mine work 'like old'. The tubes and floats are different sizes. The new float is so large it will not fit inside the old tube. The clearance from float to tube is different. The connectors are different, but those things don't matter. The tube is held in place by a small cap with 2 screws, and has a hole drilled at an angle to let air travel that lifts the float. The old unit has a 3/32" hole and the new less than 1/16" (picture attached). After drilling that to 3/32" mine works like Randys. Today I tried it on my HS6 and found I can set either UNI-SYN on either carb for as long as I want and the RPM doesn't change and the float level remains constant. Before modifying mine (a second time) I could put it there for a second before the RPMs changed.

The "Synchrometer" shows 12dm3/min at 950RPMs. At 1500RPMs it's drawing 18dm3/min and at 3000 the meter is pegged at 40dm3/min. At any RPM, the UNI-SYN can be adjusted with float centered so "balance" can be checked. Either UNI-SYN can now be set on the input side of a hair drier and adjusted so the float is centered. Before modification, my UNI-SYN would not register anything with the same hair drier.

I'd like to thank everyone for the input and suggest if you have a UNI-SYN with "CHINA" on the front, and it doesn't work well, re-drill the hole, but be careful to not let the bit wonder into the adjacent screw holes.
 

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Out standing TKH, after following this thread and thinking the next time I run across my Uni-Syn to remember to toss it in the bin.
With this info I did dig it out and examine the orifice in question
as mine has no markings what so ever and it is the small hole.

This is what a forum is all about, the sharing of information
Can't wait to check my carbs as I have the GP 175 trip set up and I know # 1 is off.

Thanks and happy motoring

Tony
 
I'll second that, Tex. Good job! Glad you were able to make it useful. Checked mine, btw, and it's the big hole variety.
 
TexasKnucklehead said:
I am sure the "MOD-A" and "MOD-A CHINA" are different. Forgive me if I'm beating a dead horse, but for future reference I'd like to show what I found and corrected to make mine work 'like old'....
Click to expand...
Excellent, indeed! Perhaps you should send your findings to Edelbrook. If they still care about their long-standing (otherwise) great reputation, they might like to know about this?
 
I looked on the Edelbrock site and don’t even see the UNI-SYN listed, nor did I find an email address. I did find mailing addresses and may send them something.

Sometimes you just can’t beat a dead horse enough.

Since I still have Randy’s tools, I decided to check the synchronization of the carbs on my TR6 today (in what locals think is blistering cold). It has been running fine for years. After warming up the engine and removing the cover (air filters get very dirty in only a few years). At idle, I used the syncrometer to measure the rear carb at 18dm3/min and the front at 25dm3/min. Without correcting it, I used both UNI-SYNs to see they were indeed unbalanced (either showed a difference of about a full graduation or ¼ the length of the tube). Without changing anything, I wedged the throttle at about 1500RPMs and measured again. Now both carbs were measuring the same with any of the 3 tools. It is interesting to note that the relative placement of any of the tools will vary the readings –that is, the same sets of carb flow holes must be covered the same amount on each carb to have consistent readings.

Anyway, I knew the linkage was synchronized, but the idle was slightly off. Turning the idle stop screw between ¼ and ½ turn balanced them and all 3 tools agreed.

Then with the idle balanced and reading 18dm3/min at each carb, I put on the UNI-SYN and turned the idle stop screw until the float moved one full graduation. It took only ½ turn. The syncrometer now showed 35dm3/min on one carb and 20dm3/min on the other. (I was surprised that both changed that much.) Both UNI-SYNs agreed the idle was unbalanced by a full graduation. Turning the screw back ½ turn, both UNI-SYNs agreed balance had been restored and the syncrometer measured both at 18dm3/min. Then I stuck a length of heater hose into the carb body and rotated the screw ½ turn back and forth. I couldn’t hear the difference –of course that’s not to say someone else couldn’t, and I didn’t try going from one carb to the other (since any change affects both).

I think using the UNI-SYN at lower RPMs is easier if you don’t adjust the float to the center. That’s because in order to pull the float up higher, the diaphragm must be closed more to create the vacuum needed to lift the float. The more the diaphragm is closed, the more it can affect the air flow into the carb. I adjust the diaphragm so the float barely rises to the bottom graduated line. As I stated earlier, closing off some of the carb holes with the tool may affect the engine speed (and measurement) –but it will do the exact same thing on the other carb if placed in the same relative position. Since the UNI-SYN is ‘relative’, it doesn’t matter if you close or neglect to close off holes, as long as you are consistent.

Now, I know more about balancing than I care to. But after owning a specialized tool since 2005, I finally understand how to use it.
 
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