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Carb Sync How-To


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My searching skills may need some work, but I can't find it. Can someone post the instructions on how to do a carb sync on a 2nd Gen. Please keep in mind my mechanical ability is such that the instructions really need to be written in crayon. Thanks!

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Here you go. It's a piece of cake.

 

http://www.venturerider.org/forum/showthread.php?t=258

 

One of the statements in that thread is...

 

"NOTE: Prior to synchronizing the carburetors, the valve clearance and the engine idling speed should be properly adjusted and the ignition timing should be checked."

 

I have not yet seen anywhere where it tells a guy how to check the ignition timing on either a 1st or 2nd gen. Can anyone enlighten me (and others) on this...??

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Wow great instructions and illustrations. By any chance someone have similar set of instructions for a 1st Gen MKII (89 VR).

 

I don't believe it's any different for a 1st gen as they are essentially the same engine/carb setup .... someone correct me if I'm wrong.

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One of the statements in that thread is...

 

"NOTE: Prior to synchronizing the carburetors, the valve clearance and the engine idling speed should be properly adjusted and the ignition timing should be checked."

 

I have not yet seen anywhere where it tells a guy how to check the ignition timing on either a 1st or 2nd gen. Can anyone enlighten me (and others) on this...??

 

I found the answer to my own question in the following 2 posts...

 

http://www.venturerider.org/forum/showpost.php?p=475692&postcount=4

 

http://www.venturerider.org/forum/showpost.php?p=475843&postcount=6

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  • 8 months later...
I know both operate on vacum, but will the vacum only carb sync gauges do as well as the liquid filled manometer gauge or would I be wasting money buying a NEW 4 vacum gauge set off ebay for $68.95 + $8.00 shipping? Thanks in advance for advice. :thumbsup2:

 

C.R.

In my opinion, the four-gauge set is far and away the best tool available for this job. Up to about 6 months ago they were still available from several sources for under $50. But I just checked my old sources and all have raised the price. The one that was the lowest seems to be totally gone! the best price I found today was $56.50 + $12.50 on Amazon:

[ame=http://www.amazon.com/Carburetor-Synchronizer-carb-Gauge-cylinder/dp/B004MSJ7E6]Amazon.com: Carburetor Synchronizer carb sync Gauge 4 cylinder bike: Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41G43GKBZcL.@@AMEPARAM@@41G43GKBZcL[/ame]

 

As for the other tools, I think the one with mercury is excellent, but can be touchy, easy to break or loose the mercury. The one with metal rods is just junk. The one with blue liquid is absolute total unmitigated crap, worth a LOT less than 1 cent. If someone tries to give you one, it's kinda like they are stealing $100 from you the first time you try to use it!

Goose

Edited by V7Goose
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Okay. I am going to buy a carb sync tool today

 

But, I have noticed that most of the ones, for sale on the Internet say that they come with 5mm adapters and that the 6mm adapters for the Yamaha should be purchased separately. I have studied "Synchronizing The Carburetors" from the technical section and it really looks straight forward and simple, however, I don't see these adapters. What do you do with the adapters? Are they even necessary?

 

Here is a direct link to the one you referenced at Amazon. (This cuts Amazon out of their $2) http://www.thealphamoto.com/servlet/Cart?cart_id=23156921

 

Tell me what's up with the adapters. Do I need them, or is everything I need included in the package on the link above?

 

Thanks.

dana

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Nothing is needed for our bike but a tool that reads vacuum, some restrictor to reduce fluctuation (the gauge set comes with them) and the tube to slip on the vacuum port nipples.

 

The gauge sets come with threaded metal tubes that are used to screw into the vacuum ports of many bikes that do not have a permanent nipple in place. We do not use those.

Goose

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I am really a firm believer that one vacuum gauge may read different from another, so I made my own using just one gauge with 4 shutoffs. The shutoffs act as a the restrictor as well. Total cost at the time was about $40.00 I think. And I got my own homemade tool. It works great, but you don't have the advantage of seeing all four at once. For me that is not an issue. Having just one gauge also saves time to check that all the gauges are still reading the same.

I'm going to add to the design of this unit today. The 4 plastic tube leads will be shortened and then a coupler inserted to add some rubber vacuum hose. The plastic tends to get hot, and then the ends tend to get loose and I've even had the tubes collapse from the heat of the engine.

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  • 4 months later...

I have a pair of round vacum gauges I mounted up to sync the carbs on my legends car (fj1200) It worked OK but the detailing is not as fine as the stick tool I see most of you all refer too. About how much vacum do these pull?

Part of my interest is my milage seems to be all over the place compaired to my preceeding ride. My Kawai 900 was about 43-44 on my normal type rides say under 70 and expressway long distance was around 39-41-42, This bike is all over the place under 70 I have been from 33 to 41 expressway 35-38. Just wondering if maybe the carbs are a bit outa whack. Milage is only 8600 + - a few hundred.

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I am really a firm believer that one vacuum gauge may read different from another, so I made my own using just one gauge with 4 shutoffs.

 

I agree with you. Thats why I made up a 4 port T fitting to check my Carbtune using one vacuum source. Fortunately they all registered the same reading. I'm not sure what I would have done if they didn't. Maybe a restrictor?

 

I'm not sure why Goose doesn't like the Carbtune. Mine has worked great for the handful of times that I have used it. Does the Carbtune have a reliability problem?

Of course I always have the mercury sticks if the Carbtune fails

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OK for grins I just hooked up my gauge. Evidently I had read about building one of these as it had a valve inline you could restrict or completly shut off the line. If wide open the needle moves around so much you cant really tell where it is. Bounces from like say 10 to 18-20. When you close it off to where it is steady its about 10. So am I barking up the wrong tree with being able to use these gauges? Do I need to maybe build a vacum chamber to stableize the vacum? I guess I could use a piece of say 1/2" pvc and cap the ends and port it. Or just turn the valve untill the needle stabilizes and use that reading?

3/7 OK I read up on using gauges in place of the liquid type. It seems you need a restrictor inline or else it bounces to much. So I got a couple today. Tried it out and all 4 carbs appear to be the same. I say appear because it still has more bounce in it that I would like. Needle moves about 8-10 lb. So I think maybe the chamber may be next thing to try. Shoot I'd try a pop bottle or something if I didnt think it would collapse it. So of the fuel pressure/vacum test gauges have "snubbers" built into them I think. The gauges I'm trying to use are just "dash mount" types.

Edited by djh3
More info 3/7
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